Not on the wall socket
but I have stumbled upon home made extension cables where the wires were mixed, so as a rule, when I ordered a new extension cable from our worksjop, I would test it before I use it.
There's just one more day to get through before the weekend is upon us so burn a few minutes by chortling at the misfortune of others with On Call. Today's tale from the telephones comes from "Steven" and concerns a mysteriously malfunctioning printer. "I was called to look at an old Mannesmann Tally printer that was printing …
It is EXACTLY this sort of fault that PAT testing was introduced to deal with! Along with stress-induced opens to the earth wire, another potentially nasty problem with cables and extensions leads.
You can check for mixed wires with a multimeter, or plug it in and used one of the cheap (£10 or so?) plug testers that warns of swapped or missing connections. But if you have a lot of kit, small tech company, etc, then it probably makes sense to buy a proper tester like the Seaward PrimeTest 100 (£350-ish) and look after all your stuff with regular testing (it will do insulation / leakage tests on the appliances as well as cable cross and lead resistance on IEC leads and extensions leads, etc). For a bit more (£450-ish inc VAT) their '250' model will also test RCCB trip times, etc.
But if you have a lot of kit, small tech company, etc, then it probably makes sense to buy a proper tester
Training courses are available at many local colleges and not terribly expensive too. For a small company the expense of a bit of kit and training up one or even two employees would probably pay back in a couple of years.
And you will avoid the cowboys who deliver this service for a fee. They waltz into an office, plug in, push a button and hope. They rarely do proper visual inspections and they rarely actually understand the results they get. We had one a few weeks ago who stuck a "passed" sticker on a desktop UPS, despite the fact that his insulation resistance test had actually killed the device (I suspect probably just a blown internal fuse, but haven't yet checked) so the remaining tests were worthless. At school, the children report that following PAT the computers "usually don't work properly". Some won't boot, some boot but slowly, some won't talk to the network.
Worth noting that the regulations don't actually mandate (despite what some companies will tell you) 12-monthly inspections. When engineering at a radio station many years ago I did most of the PAT and "broadcast chain" equipment in racks - being officially "portable" but in reality screwed down - got tested as little as possible, perhaps every five years. Conversely things like extension leads which were out and about quite a lot had visual inspections every time they came back and a full-blown PAT maybe as often as every quarter.
M.
The other important thing to note is that PAT stands for "Portable Appliance Testing", and it's supposed to involve testing portable devices, like laptop chargers etc.
That UPS that's too heavy to move without removing the battery? That doesn't require testing.
You also don't need to have a qualification of any sort, you just have to be "competent".
Not to mention, it's stressed several times in the guidelines that a visual inspection is the most important part. Even if your charge passes the tests, if the insulation is flaking off, you should probably get it fixed or replaced.
A colleague of mine once managed to drape the lead for a power drill over the top of a portable gas heater that melted the insulation off exposing bare copper cables. We sent the damaged drill to our usual "Test & Repair" place, and a week later it came back with a brand new paper sticker on it telling us it was ok, but still with the bare wires exposed.
Reminds me of the calibration house that used to annually certify our digital multimeters. We suspected that they were certifying them without actually testing them, so we opened one up, diddled its trimpots well beyond its stated calibration limits, and sent it off. Sure enough, back it came with a fresh sticker -- and still horribly out of calibration.
it's supposed to involve testing portable devices, like laptop chargers etc.
That UPS that's too heavy to move without removing the battery? That doesn't require testing.
The definition of "portable" is a bit vague. The item I mentioned is a desktop UPS, IEC mains in, single battery, eminently hand-portable. I've always taken it to mean anything which could be moved in the general course of its use, and particularly anything which has a removable mains lead. This means things like those large wheeled air conditioners or industrial 3-phase electric heaters (we have two) do count.
You also don't need to have a qualification of any sort, you just have to be "competent".
Yes, but the courses are (relatively) cheap and if you are a small company looking to do this to save money and hassle, chances are you don't have anyone "competent" to hand. Always worth being sure.
Mind you, definitions of "competent" vary. When I did domestic sparks, the NICEIC registered me as competent based on a degree in electronics and an inspection of a couple of jobs I'd done. I also had "the regs" (C&G 2381), but they weren't hugely fussed about that. Nowadays they want quite a lot of paperwork which could easily involve several thousand pounds of college courses, and my degree doesn't seem to count for much.
"Mind you, definitions of "competent" vary. "
Yes, this. Back when NVQs where first being introduced, it was clear from the guidance that anyone who could produce evidence of competence in an area could be automatically passed on one or modules. The reality on the ground was that the only acceptable evidence was a completed NVQ module and assessment certificate for the module.
The NVQ modules (all subjects) were assessed by the training body. Often, in those early days of payment by results through private tutorial colleges anyone who could breath would be passed. The assessors were put under incredible pressure to make sure they did.
Not to far removed from the recent scandal about the London minicab test, though those were fraudulent from start to finish.. And wasn't there something along those lines with the driving license theory test too?
""You also don't need to have a qualification of any sort"
Yes I came up against that - 'did you wire this (fused spur)'?
Yes
You just have to be a "competent" person to do that.
I've re-wired three houses and none have caught fire.
But have you got any qualifications?
'A' level Physics
That's not what I mean
So it doesn't count?
Dunno!
A couple of years back we had to get a Fixed Wiring Testing Certificate for our main building for insurance purposes - first we'd ever had to do.
Not unexpectedly if through up a few "horrors from the past" which needed rectifying. However, NONE of them matched what our "jobbing electrician" pointed out after it had been done by some other mob of so-called "qualified" electricians:
In the main "electrical room" where the main building DB is, the incoming TPN goes through a three pole fused isolator (big cartridge fuses each of 100A) upon which the inspecting electricians had put a nice "PASSED" sticker on complete with signature and date.
Our regular jobbing sparky pointed to the big 32mm hole in the side and shook his head.... "How the f*** can that have passed?" then put a blanking plug in it.
The same mob had not long before done PAT testing of everything in the building. Needless to say when they get calling for retesting the following year they didn't have their calls returned.
And what it is about PAT testers where they seem hell bent on putting their "TESTED PASSED" stickers over the part of PSUs (laptop, plugin etc) which gives the specifications? PITA that is.
pre IT I was an electrician for 30 odd [VERY odd] years, final years were spent as maintenance spark for a fair sized factory, we had PAT running sort of regular, and had decided that the man on nights would do it, as most of factory ran the 6-2 / 2-10 shifts, anyhow, ONE man in a fair sized factory trying to complete all PAT for its annual completion and big tick in the DONE list got to be very awkward, as we worked out that even if we had ZERO issuess on the floor, and NO project work, of which there was lots :o) that the 12 month rotation MIGHT be completed in two years, so we started adding a retest date of two years to each item, and lo and behold we got our big tick in the done list ffs :o)
have to add, we WERE professionals, and the PAT was completed properly and thoroughly for each item, which may have explained how it took so gaddamn long
When I worked in industry where there were 50 ton punch presses etc. run on 3-phase delta 220 volt circuits with one phase grounded. There were problems when moving equipment it might result in the motor turning backwards. I built a small tester with three ne-2 bulbs indicating rotation (left & right) and ground-neutral voltage. I then went around rewiring all of the plugs and sockets to conform to the majority.
There was a 4-slide machine where every time a wire was threaded from the wire straightener to the machine there were sparks. The operator said, "No problem, it's always done that." I got the shop foreman and he allowed me to look at the plugs and sockets and, sure enough, the neutral and ground were interchanged.
Safety is important.
Oh yes. Fried equipment after a test. We lost three pieces of expensive lab hardware (microwave / HF stuff) at university because the cowboys of our electronics workshop insisted on testing this. Of course, the university is not insuread against that. F'
The institute did foot the rather hefty (for our group, small group, not a fully chaired professor, etc.) bill - and we got the ok to tell them to bugger off when they tried to enter the lab. We usually let them in but refused to let them tough anything sensitive.
When I was working as a delivery driver for a local pharmacy (ie, Drug Runner), we moved to a new premises. The back door, through which the pharmaceuticals, etc. were delivered from the wholesalers, and through which I took the deliveries out to the customers, was a steel security door, and had no means of attracting attention from outside (and no windows in the adjacent wall). I purchased a wireless doorbell from a local electrical shop and installed it. Some while later, the PAT tester came from Head Office to test all of the appliances, including the plug-in annunciator for the doorbell. After he left, there was a thunderous banging on the security door, the doorbell was no longer working, in spite of it passing and being given a sticker, the PAT test had fried the circuitry. Bought a replacement and installed it, adding a notice "Please do not PAT test this bell". 12 months later, repeat performance led to another dead doorbell. The following year, as soon as the tester arrived, I unplugged the bell and put it in with my deliveries until after he had gone, at which point I plugged it in again (and it still worked). When I left the company, I told the Branch Manager to be aware of this subterfuge, but I don't know whether she did or not.
"Oh yes. Fried equipment after a test. We lost three pieces of expensive lab hardware (microwave / HF stuff) at university because the cowboys of our electronics workshop insisted on testing this. Of course, the university is not insuread against that. F'"
Class 1 tests run against a class 2 device?
Either that or overzealous probing with the flash test probe. 3750v tends to be the winner in a contest involving modern electronics., That test was originally designed for power tools.
The upthread comment about computers being damaged was possibly due to use of the 'tools' earth bond setting, that on my Clare tester, pumps 20 amps through the earth conductor.
Fine on a 3kw heater, notsomuch when the clip is attached to a d-sub connector on the back of a PC and tries to put that 20A through a motherboard trace.... even the 'Audio-visual equipment' test of 8 amps is a little harsh.
When doing PAT, i tend to use the 200mA continuity function on the megger MFT rather than the normal earth bond
Very much this =>
The problems reported in this thread are almost certainly down to incompetents running tests that are inappropriate for the class of equipment. We had our technician do the PAT testing on all equipment, including very expensive lab test gear using one of the fairly basic Seaward testers without any problems.
And as other commentards have alluded to, the test interval "depends". On stuff like servers, fixed PCs that no one can trip on the cables, etc, then when new* and at 3 year intervals is probably fine. For equipment subject to moving but benign environments like kettles, laptop power supplies, etc, then yearly makes sense. For stuff with a high risk of damage or more serious risk if they fail like frequently used extension leads, building site power tools, etc, then 3 months might be more appropriate. Also as already mentioned the inspection for damage or an incorrect fuse rating is critical!
https://www.hse.gov.uk/pubns/priced/hsg107.pdf
[*] I don't trust suppliers (more so if folk bring in their own or 2nd hand stuff) and you also then have a PAT database that doubles up as an asset register, etc.
I had a mains lead (from China that had ALL THREE wires connected wrong. I don't normally check mains leads, but this one looked particularly cheap & nasty, so I just did a quick ohmeter test and bingo. AND the error was in the IEC end, all moulded-up and inaccessible.
I've a creeping suspicion that's who wired my house.
Turning the radio on or off in the office room causes my desktop 'puter to wake from suspend! And it's not even plugged into the same power outlet! That is, if a wired keyboard is plugged in.
My work computer is plugged into a 4-gang extension lead, which is plugged into another extension, which is plugged into another extension, which is finally plugged into the wall. (Why didn't the builders of this Regency town house, two hundred years ago, bother to put in extra sockets eh?)
When the large laser printer next to me (also at the end of the chain), fires up to print something, it causes one of my monitors to click off and back on again.
I'm sure its fine...
(Why didn't the builders of this Regency town house, two hundred years ago, bother to put in extra sockets eh?)
Victorian ones are no better. Currently my electrician is cursing every time he takes a faceplate off a light switch - no earth cabling to the switches, despite reasonably modern spotlights in all the ceilings. Turns out they only earthed the spotlights, and couldn't be arsed with the switches, so now I've got channels in all the walls, floorboards up aplenty, and a large bill to deal with.
I know a place with several physics PhDs who do this all the time. Meanwhile, into these "daisy chains" of extension blocks they have plugged multiple "plug top" SMTP mains adaptors. I don't think despite their "brains the size of planets" they have any concept of SMTP "in-rush currents"... Hmmmm
Also, I'll often see them set up some bit of kit in one corner of several special "tables" (I won't say what type as that gives too much away). No particular reason WHY that corner, that's just where they have decided to put it. Usually as far as possible from the nearest power outlets or any associated equipment (PCs etc) which may need to be connected.
Their solution? Move their equipment? Oh no.... NOTHING as sensible as that. Just stretch every cable to the maximum. Mains cable, USB, network, doesn't matter - "they" think they are all "stretchy"...
And yes these people REALLY DO have PhDs in physics..
I had a fire inspection at home, one thing they don't like is chaining a multi-socket block onto another multi-socket block. Preferred is a two-faced tower thing that can have as many as 10 sockets on, which is the same as three x4 blocks since two of your sockets are occupied by the blocks of the plugs. So I've switched to towers. Obviously not for small children or pets to play with, but nothing electrical is; arrange furniture accordingly. These may also come with a promise, for what that's worth, of "surge protection", and/or a couple of USB charging sockets.
Mostly something from the US and other countries with such anemic wiring. They have 10A sockets at 110V, so 1100W if you're running a resistive load*. That's not even enough for a large space heater, so it's very easy to overload if you start chaining equipment. five somewhat-dated PCs at an office desk and your plug strip is on fire. British sockets are 13A at 230V, so about 3KW - you have to really put some effort into overloading that.
*A bit more for SMPS.
Years ago I bought a flat that had been built in the 60s, and as I was abroad for a while, rented it to one of my friends for a few months. He complained that he occasionally got a shock while in the shower. Odd! I had wanted to redo the wiring anyway as it was still using the wooden external conduit, so set about doing that with my dad (who's an electrical engineer).
It turns out that ll the wiring in the flat was perfectly done, but the Live and neutral wires coming into the fusebox from the external mains were swapped, in effect meaning that all the 'neutrals' were live, and none of the plugged-in appliances were fused. Luckily no big tragedy ensued, still grateful for that as it was a recipe for major disaster ------------>>>>>>>>>>>
In the early '80s I owned a house in Ireland. It had electric hot air heating which was stupidly expensive to run so I thought I would free up the space by removing it. Before starting I thought I had better check my plans with my "sparky" mate.
Guess what he found.
The live and neural feeds into the fusebox were the wrong way round.
He fixed the fault and I then stripped out the heater.
as stated used to be a spark, 30 odd years, and if the appliance has need of a plug that the end user can fit, then it doesn't really matter which way round the Live / Neutral go, it only mattered that the EARTH went to the right pin, and that was one of the reasons the earth was a Green AND Yellow stripe
I believe the new colours are not what I used to work with so not able to say that, but will stand by the above for what its worth - IEE regs 13th then 14th edition, cos I is an old fart
This is actually a big deal for the old AC/DC radios and TVs. Switch the connections around and you could end up with a live chassis. A definite hazard to work on to say nothing of the further danger to casual users that the loss of the plastic volume control knob might entail.
then it doesn't really matter which way round the Live / Neutral go
Actually it does, and not just for the reason @Robert 22 gave.
Usually the switch is on the phase/live. Now you should unplug things before playing (unless you need to test it while powered up) but we don't all always think to do that (or have been unplugging/plugging in several times while trying to track down one of those faults and are so sick of it we're approaching 'suicidal' anyway). And when the thing is plugged in, and what should be 'neutral' is actually 'live', you find out that things are live that should never be live. Heaven help the poor person who has a knee idly resting against a workbench while they test such a badly wired unit.
Maybe "Correct Pin" would be less risky to some idiot using forum comments as a source of "how to" instructions..
IIRC Earth/Ground (Green/Yellow) is connected to the TOP pin, with Live (Brown, continuing the use of UK color standards) to the LEFT pin (Right when looking from the back of the plug), or the one with the fuse inline.
Connecting Earth/Ground to the (Literal) right pin has the potential* to ruin someone's day.
*Accidental punny in-joke, sorry.. ;-)
You have some seriously incompetent electricians over there!
I own one of those 3-neon light testers. It has alerted me to problems with the wiring in several cases. It lives in my toolbox and is frequently used. The daughter recently purchased a 1950's house, built before the PE "earth" or "ground" wire was required. All kinds of room for improvement. I found a GFI without a ground connection. Not much good, that.
I also found something I had never seen before: broken wires. In two cases, the person who had wired the outlet, had used the "back wire" connection (faster, but less reliable than the screw terminals). The wire had broken and disconnected. Luckily, there was enough left in the box to strip and connect using the screw terminal, and I rewired the remainder to make sure. I'm pretty much convinced not to use those back-wire connections ever again.
"I found a GFI without a ground connection. Not much good, that."
Actually, that is a recommended practice to help improve safety with 2-wire circuits. The GFI doesn't work based on the ground wire. It actually compares the current flowing in the line versus the neutral. If they're equal magnitude, things are ok. If they aren't equal, that means current is flowing somewhere is isn't supposed to go, so it opens the circuit.
The ground wire in a grounded circuit shouldn't carry any current in normal usage. It's designed so that if something goes wrong (like a damaged wire contacting a metal enclosure) it carries enough current to open the upstream breaker. Once you understand this, lots of electric code makes more sense (like the rules about when neutral and ground must or must not be bonded in a panel).
The device you describe in your post is an RCD - Residual Current Detector. This identifies the amount of current going "missing" from the circuit (the live and the neutral) and when this exceeds a set amount it will interrupt the supply. (typical values for residual current are 10mA, 30mA and 100mA for large equipment)
A GFI type device relies on the current flowing through the ground circuit through it to detect the issue and interrupt the circuit. The drawback with these is that if the current flows to ground through an alternate path (eg. a person), the GFI will not detect this and interrupt the circuit.
I'm pretty much convinced not to use those back-wire connections ever again.
They seem to be controversial among US electricians, if you read some of the online forums where electricians (licensed ones, not just DIYers) hang out. The broad consensus seems to be that for US receptacles and switches the back-wire connections have improved over the years, but some people still don't like them.
Personally, I avoid them myself. I also wire receptacles on the same circuit using pigtails rather than wiring through the receptacle. Code allows the latter (at least the last time I checked), but something about it irks me, and I've seen inspectors recommend against it.
"He complained that he occasionally got a shock while in the shower."
Happened to someone at work recently and being a millenial he took the obvious course of action .... he put a poll on one of our slack channels asking "I get a small electrical shock when I touch my shower - should I call an electrician? Yes/No"
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I once built a really solid dimmer system for the pub I used to frequent, and before installing it, I wanted to make damned sure the wiring in the pub was up to standards. What I found in the basement was, let's say, interesting. Green and yellow wire = live, brown = neutral, blue = earth? No problem! Any other permutation? Equally likely.
Probably the same electrician
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I don't know about wiring the neutral to the earth pin but I'm sure I remember that if you mix the neutral and live that if a fault develops that the fuse won't blow and you'll have a toasty (potentially live - if not double insulated) appliance on your hands.
I argued with my Dad over that. His assumption was if it works it's fine.
In that case you are mostly right, it is an unsafe situation at the least. But there is a good chance the appliance won't have a problem as a single, internal design worldwide is a lot cheaper, so the only difference with a continental version of the appliance is the plug.
In a (relatively) modern TN-S system (separate neutral and PE), switching or connecting neutral and PE would immediately trip a breaker because of the current mismatch in line and neutral.
Whether the fuse would blow depends on the kind of fault.
I reckon the faulty printer in the story was connected to a TT system, which would have been common around that time. Switching neutral and PE can have quite funky effects on the voltage there, not to mention bugging the worms and moles.
If the circuit doesn't have an RCD, a plug wiring mistake is potentially lethal. I had a very close shave once when I was alone in a building at night. My boss, a trained engineer who should have known better, had added a skirting board power point and wired it live-neutral reversed. It wasn't his job to do that, but working on a local radio station we were used to taking short cuts to be helpful to the programme making staff. A couple of professional reel-to-reel tape recorders, built into table height steel trollies, were plugged into the errant double socket. I had been woken at 2.30 am and called out because one of these had stopped working and it would be needed at 6 am to prepare for the morning broadcast. A quick check showed that it had blown its mains fuse so I replaced it and switched on. Luckily for me, the fuse immediately blew again and I realised more investigation was needed. I then discovered that although the plug looked OK, the whole trolley had been wired earth-neutral reversed. The fuse had blown because I had moved the trolley so it was touching its properly earthed neighbour while at mains voltage. If the machines hadn't been touching I could so easily have put a hand on each. I drove home quite shaken. Both faults had existed for some time with no apparent ill effects, and despite almost ubiquitous RCDs nowadays, I have been fanatical about correct mains polarity ever since.
Swapping live and neutral won't blow the fuse if the problem is a short from (actual) live to ground. If you have RCD protection though, the RCD will blow in this case, so you are still protected. If the fault is a short between live and neutral (which obviously? won't be picked up by the RCD), then the fuse will still blow.
So in a house with reasonably modern electrics, I'm sorry to tell you this - but your Dad is probably right :-(.
Can someone explain why which way round the live and neutral are matters.
We are talking about alternative current, it doesn't have a direction of flow (or more correctly the direction of flow alternates). 50% of the time the 'live' will have the higher (or equal) voltage and 50% of the time the 'neutral' will have a higher (or equal voltage)
As far as the electrons travelling through the wires are concerned, there's no real difference between the two wires.
In real life, one of those is connected to the ground and called 'neutral'. As long as you've got your feet on the ground (or thereabout), you're indirectly connected to it. That's why touching the other ('live') wire hurts - you're now connected to both.
Technically it would be safe to touch the 'live' wire while in free fall or otherwise disconnected from the 'neutral' wire. You still shouldn't try it though.
(This would be the same with DC, only you'd need to consider polarity instead of the phase.)
PE is also technically identical to neutral, though (in modern installations) for safety reasons has its own wire. E.g. an RCD needs to be able to distinguish between neutral and PE - there's no current supposed to go through PE at any time, while the current through L and N should be identical. If it's not, something's wrong.
In older TN-C installations, PE was just connected to N at the socket - at least in continental Europe; not sure about the UK. This had the interesting side effect of electrifying anybody who touched a device connected to that socket when there was a problem with the neutral line and the device was switched on.
(US wiring)
PE is NOT identical to neutral. It's connected to the same point at the breaker panel, but while neutral carries current, PE does not.
So a given point on a PE wire should be at ground potential, 0 volts, the same point on a neutral wire will read some slight voltage relative to PE, dependent on the current being carried and the resistance between the point being measured and the breaker panel.
PE being Protective Earth is connected to the Earth with a ground pin at home and/or the local street transformer. The Neutral is connected to the Earth at the 3-phase transformer somewhere in the neighborhood. In my country usually a 10500V to 400V one. If you use one phase with a neutral you'll end up with 230 VAC
I was in a flat in Edinburgh where, the neutral was somehow connected to a cast iron external soilpipe. It "worked" until the downstairs flat wanted a new bathroom so "teed" in using a modern plastic bit of pipe with rubber connectors thus breaking the continuity to ground.
Electrically all hell broke loose :)
Technically it would be safe to touch the 'live' wire while in free fall
At the end of that fall you now have two problems, though. Maybe not so much when landing on a large enough stack of styrofoam or similar.
or otherwise disconnected from the 'neutral' wire. You still shouldn't try it though.
There's birds[0] sitting on power lines all the time.
[0] except storks and similar, obviously.
Technically it would be safe to touch the 'live' wire while in free fall or otherwise disconnected from the 'neutral' wire. You still shouldn't try it though.
Depends on the frequency of said live wire! Though at 50Hz 240V it could be considered DC for this purpose. Crank frequency or voltage up sufficiently (a lot) and capacitance becomes something you need to worry about.
Hmmm...
>(This would be the same with DC, only you'd need to consider polarity instead of the phase.)
I don't believe AC Phase or DC Polarity matter.
It's Voltage difference/Potential difference/P.D. (Be it AC or DC) that causes the current flow and hence the electric shock.
The difference between 0V and 100VDC and 0V and -100VDC is still 100 volts...it's just the direction of the current that would be different, not the magnitude...
....or have I missed / mis-read something?
If I have, could you explain the bit in brackets? :-)
Three phases coming in, each is a different Live. Neutral is not transported from the power plant, but from the local power distribution station, where the phases are mostly balanced so that Neutral can be provided as a return path to the customers. However, Neutral is only at Ground level at the power plant, so there can and will be voltage differences between Neutral and each customer's Ground, depending on the resistance between the Ground at the customer and the Ground at the power station.
Neutral is usually near, but not connected to (at least in your house), earth. I have an old clothes iron with a 'heating' indicator which can't be used on modern wiring because the bulb is wired between neutral and earth, about 4V AC. If you use it now, it always trips the rcd because it detects current running out of live which doesn't return via neutral.
On broken wires, I had to rewire a house because the cabling, installed on the 1940's, had rubber insulation. It had perished and exposed the copper. Entire areas of wall were live. I have no idea how it hadn't burned down.
Soon after we moved into our first house (1844 cottage in a village), my wife complained that she was getting a tingle whenever she touched the taps in the bathroom handbasin. I checked them with a multimeter, and found that they were securely earthed. I asked SWMBO to demonstrate how she was getting this tingle from an earthed tap. She ran some water in the basin and told me to put one hand in the water and touch the tap at the same time. Sure enough, there was definitely a voltage difference there. Checked the plughole to earth, and it was showing about 50 volts AC. Eventually traced the fault to the overhead wire running to the shed. The flat twin and earth was suspended from a steel wire rope catenary which was bolted to the brickwork just outside the bathroom, and the insulation had deteriorated and cracked, allowing rain water to penetrate to the copper. The resultant current was then running through the damp brickwork, along the lead waste pipe, and up to the brass plughole in the sink. I replace the lead pipe with a length of modern plastic waste, and the problem went away, but there was still the leakage through the brickwork to contend with. I eventually replaced the FT&E across to the shed to make it all safe.
Some time later, I installed night storage heaters (no gas in the village). When the electricity company representative called to make the final connection to the mains, he said he couldn't do it because there had to be a Earth Leakage Trip connected to an external earth rod. I duly purchased a copper clad steel earth rod and drove it into the soil outside the front of the house, and installed the ELT inside. Different Electricity man comes back and says "Oh, no, your PME has to be connected to the earth rod as well." But that would prevent the ELT from operating, as any earth fault would bypass it straight down the wire to earth. Electricity man was adamant, and waited while I run said earth wire, before pressing the yellow test button to demonstrate that it was working. As soon as he left, I whipped out the side cutters and removed the offending earth wire, before testing that it worked properly to my own satisfaction.
As said in the article:
The fuse detects abnormal current draw on the live cable.
Screwing that up means that in a short or other potentially life-threatening situation, you hope the big breaker pops before whoever it is starts smoking.
In a home, that's pretty certain. For a business feed, less sure. For industrial, you'll never get the smell out of the furniture.
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I think you are wrong on your assumption of the French electricity, it is normal 230V phase and neutral neutral. And that's how you can easily get 3 phases 380/400V.
You may be confusing with the USA where they tend to create 230V with two 110V in opposing phase (and that'w why it may be very tricky to get 3 phases and they rely on atrocities like rotary converters)
Just withdrawn my partially-correct post above.
Thanks to Oliver2553 for pointing out the I'd made a pretty basic mistake on French norms.
My parent post above holds for British installations and most of Europe is similar (230V).
For other areas, you need to check. Most equipment has tolerant power supplies so they won't know the difference, but your fingers will.
First, your appliances will work just fine if you swap Live/Neutral. However, your fuses (or circuit breakers) and switches won't be as effective, so you will be unsafe. Long explanation:
The Neutral and Earth wires are connected together somewhere. In the UK, this is often at the connection point where the wire to your house ends, just before your electricity meter. In that case the electricity supplier will have lots of places where their combined neutral/earth wire is connected to metal rods in the ground.
So, if you accidentally touch the Live wire in your home, the power will flow from the electricity supplier's Live wire, through you, through the ground, through those metal rods, and back through the electricity supplier's Neutral wire. There will be a fuse in your fusebox and/or in the plug, on the Live wire, which will blow, stopping the current, and limiting the electric shock you get (although it can still kill you).
If you have Live/Neutral reversed at the fusebox, then the fuses are effectively on the Neutral wire. So when you touch the wire that is labelled Neutral, but is actually Live, the fuses won't help you. The power will stay on and you may keep frying.
In the case of a short-circuit that's just Live-Earth, not going through a human: The fuses are designed to protect against wires melting and things catching on fire, but they won't do that if they're in the Neutral wire. This may cause your house to burn down.
Also, if you turn a light off to change the bulb, or pull a fuse to do electrical work on a circuit, then you're safe - that turns off the Live wire, and if you accidentally touch the Neutral it won't matter. If you have Live/Neutral reversed at the fusebox, then the switch is effectively on the Neutral wire and if you touch Live then it may kill you.
Some appliances, for example storage heaters, nowadays have two supplies. One is from a time-switched off peak supply to charge the heater, the other is a standard non-switched mains supply to run a fan and the controller. Sometimes they have the ability to boost via one of the heating elements if the stored heat runs out. The switching is static (presumably triacs or something). It's important to make sure that both supplies are the right way round, as one having L and N interchanged could create magic smoke from the devices when both supplies are running. Fortunately the controller in the one I fitted seemed to have a lockout to inhibit the thing from charging if the supplies were crossed - but working out why the thing wasn't working led me to discover that the L and N wires were crossed on the high current input. All the wiring problems we have had in our house have been due to "professional" electricians, like the one who told us there was an earth fault on the immersion heater when he'd wired it to the lighting circuit, not to mention hiding a cheap and nasty LED transformer in the roof insulation so it melted and nearly burned the house down.
Can someone explain why which way round the live and neutral are matters.
In general, while "not as good" as done the right way, it will make no functional difference. In reality that exactly what you will get half the time in countries that don't have polarised plugs.
The main difference, is with the connections reversed, you may still end up with an appliance being connected to the mains "live" even under fault conditions after the fuse has blown.
I bought a rackmount power switcher (8 independently switched outlets) for a non-IT related purpose a few years ago, and later learned that the "made in China" item was wired incorrectly with the hot and neutral lines swapped. Since I was only going to be plugging in simple electronic items to it that ran off switching power supplies that isn't a huge concern, but I still didn't like it.
Since it was connected to a power line conditioner, one of those old school high end audiophile ones that are solid steel at that, I was able to simply open up the power line conditioner and switch the hot and neutral on one of its outlets. I marked it quite clearly that the outlet had hot and neutral swapped, plugged the power switcher into it, and when I plug an outlet tester into its outlets they all pass. I imagine any electrician who ran into it would take a dim view of my solution, but hey it works :)
Quality Chinese Engineering.
I try hard to avoid plugging any Chinese-made low cost consumer goods into the mains outlet. Yes, I know pretty much every power supply is made in China. It's the cheap, no-name stuff sold at big-box stores and by unpronounceable 6-letter vendors on Amazon Marketplace I'm talking about here.
I will go out of my way to avoid their power strips. Take one apart and you'll see why. Forged safety cert logos and other such games are the least of your worries. Many of these pieces of junk are downright dangerous. Icon is for your house.
People have been killed by off-brand iPhone chargers. There are several teardowns online which show complete disregard for safety in the pursuit of profits.
In the US, neutral and PE are connected to the same point at the breaker box, so swapped wires would still trip the breaker (which is in the hot lead) in the case of a short.
In the US, GFI is not yet mandatory on all circuits, but if it were used in that case, it should trip, as someone said, due to the imbalance between currents in neutral and hot.
RCDs are not mandatory in commercial premises - even the latest regulations give a few routes around having RCDs in new-build commercial property and regulations are not retroactive (e.g. an electrical installation done in 1997 does not need to be changed to meet the 2018 regs "just because").
Also, as I recall, RCDs were only required for certain use cases (sockets for supplying equipment out of an zone created by equopotential bonding, e.g. sockets for equipment to be used out doors) from 1984 and more generally from 2008.
Domestically though (I realise this is slightly OT) the regulations now more-or-less mandate RCDs on everything, and because they are also now emphasising "discrimination" - where only the problem circuit should be disconnected - RCDs which cover multiple circuits are discouraged. The easiest way to comply is to fit RCBOs (combined RCD and MCB) for each circuit, but that doesn't half bump up the cost. A typical MCB used domestically can be had for under £3 or not a lot more for a known-brand, but RCBOs are ten times that cost and now, they're suggesting that surge protection devices also need to be fitted, initially covering multiple circuits.
M.
The big thing I see mention of on https://diy.stackexchange.com/ (which is mostly left-pondian) are AFCI - Arc Fault Circuit Interupters. These "listen" for arcing in a circuit (suggestive of a dodgy joint somewhere), and cut the power before the sparks set fire to something. Given that a lot of modern houses are now timber-frame, I'm surprised these don't seem to be common in the UK. (And don't give me that story about "our higher voltage means less current so less danger" - US maxes out at 20A circuits. A ring main can carry 30A.)
The main reason is that the US uses wirenuts. Which are utter shit.
Other types of joint tend to fail in safer ways, partly because they're enclosed - a loose screw terminal will overheat but tends to disconnect itself before burning down the building because its inside a box. A lot of modern kit uses sprung terminals which (sans overload) are either a good connection or no connection.
The US wiring regs are written assuming fire is the primary danger. AFCIs only protect against fire caused by a bad joint.
If you're not using wirenuts then AFCIs don't really do anything much.
RCDs will both save your life *and* prevent fire. Definitely fit them.
All connections made with wire nuts are *supposed* to be made inside a junction box, which eliminates the danger caused by idiots that don't know how to use them. I use *supposed* as the same idiots are often homeowners or unlicensed 'electricians' that don't understand this.
Basically it doesn't matter how many standards you put in place, there's an abundance of idiots in every and any country that will ignore them.
I remember when I w**ked for the NHS visiting one orifice to install and set up some remote access software.
While there I was grabbed by a manager and asked to (take another) look at an issue they'd been having with a PC that had been moved. After it was moved from one orifice to another plugging it in caused the entire site network to crash. One of our people had been out a couple of times, and our third party support company had also been out a couple of times, but both had been unable to rectify the issue. All of this was explained while walking to the orifice in question.
Knowing that the site was using a single segment of token ring, and knowing an easy way to produce those symptoms on token ring I had a sneaking suspicion of what the issue might be. And a quick look from the door of the orifice at the PC and its network point confirmed my guess. I confidently walked over to the PC, plugged the token ring cable into the network wall socket ….. upside down ….. and then turned on the perfectly functioning PC!
I suppose I can forgive the wiring contractor for getting a single socket the wrong way up, but what I found harder to forgive was the half a dozen support visits that failed to spot a relatively simple token ring issue.
The NHS funded, private, clinic I visited never supplied anything remotely "arousing" to help. It was a tiny room which felt like a converted staff shower room, with a cheap plastic chair, a sink and an envelope file with some very "previously enjoyed" magazines with pages wrinkled and stuck together.
I still shudder now remembering having to "perform" under those conditions.
That word starts with a 'W', ends in a 'K', and has a two letter word in the middle!
For some reason my computer always censors it as w**k!
I definitely can say that I w**ked extensively for the NHS for a few years! I left because I felt they weren't paying me enough for the quality of my w**king! But when I happened to visit several months later I got the impression that the people (more than one) that took over after me felt that they were spending too much time clearing up the mess my w**king left behind!
That's probably just what they said to make it seem like they didn't need you. That's why I got out of the NHS because the IT culture in the NHS is nasty. Too much back stabbing, ignoring contractors who make sensible suggestions like "Why don't we get our own hard drive crusher so we can do them ourselves. Then we can guarantee no drives will go walk about". I was ignored, then a few years later, after I'd departed, a certain trust struggled to find someone to crush their drives for them in the timescale they wanted. So gave those drives to a "small company" that claimed they would (not vetted). That company sold the drives on EBay without wiping. Someone bought them and reported it to the papers. That trust got hit with a MASSIVE fine. I returned several years later to find "the importance of this incident" and "We now have our own hard drive crusher". The knobs.
And the other time I pointed out the flaw in the laptop encryption. I kept a laptop aside that wasn't on very often. When the encryption would lock me out of another laptop for various reasons, I'd boot the other laptop up where my encryption account wasn't locked. That would then unlock the machine I'd just locked. I informed them several times "It's working as intended. It's actually a feature". Oh fuck off then if you're going to continue to ignore me because "I'm a lowly contractor/temp". I left, and a few months later someone more senior reported the issue and oh look suddenly it "Was an issue. The laptops were set to win over the server. We've now changed this so the server wins over the laptops".
Fucking knobs. Can't stand NHS IT but then I've been unfortunate to be in two trusts with unfriendly engineers (they weren't all bad mind you). And one thing you notice when in the NHS is how they piss so much money away in different departments on specialist contractors and so much middle management. One trust I was in there was so much "Jobs for the boys" play going around it was awful. I'm sure if an investigation had been put in place during those years, some charges would of been bought on some of them.
Sorry, went on a rant :)
Shortly after I left their programmer left as well for the same reasons.
They recruited for both positions and failed to get anyone suitable. Three months later they tried again, and failed again.
Three months after that they turned our two roles into three, and increased the pay by 50%! And were finally able to find people willing to do the w**k for the offered amount.
I actually figured that my name was mud because their systems were pretty fscked up by the time the new people started more than 6 months after myself and the programmer left.
Anyone got a photo of a token ring cable and a network socket? I'm genuinely curious as having hard time finding it on Google. I wasn't into computers back when those were being used. And in college with had 10 based T and I was mainly interested in programming back then (was shit at it but that's another story) so never got into the networking side.
Do a Google image search for 'token ring mau' or read the Wikipedia article.
Type 1 cabling leads to a huge morass of cables, the Woolworths computer room had to be seen to be believed (and that was a professional install).
Later MAUs could use cat 4 cabling onwards, so physically looked little different from an Ethernet network. Cables from a token ring card used cat 4, with an optional adaptor at the end to convert it to type 1.
Oh, but they did pay royalties to...Olaf Soderblom, who claimed he had a patent on some fundamental principle behind Token Ring.
It was quite the court battle, back in the day.
Meanwhile, Ethernet, once it got past shared media, just worked. DEC, Intel and Xerox saw the wisdom of working things out among themselves so that Ethernet became cheap and plentiful.
Do an image search for "IBM Token Ring Hermaphroditic connector". That's the Type 1 Token Ring connector. It's hermaphroditic in that unlike most other connectors there's no male and female version. It's just the same connector. It's a clever idea but the execution left a lot to be desired. The connectors were huge (you could only fit 10 across a standard 19" rack), had an annoying tendency to fall apart and also used ridiculously thick cables.
As the Type 1 connectors were far too big to fit on a PC expansion card there was a 9-pin D-type connector at that end that also happened to be identical to the 9-pin D-type connectors used for MDA/CGA/EGA video connections. Cue lots of users plugging their network cable into their video card and vice-versa.
Type 3 connectors were standard RJ45 on Cat3 cabling and so were much easier to live with.
Those of us who worked with it have spent the rest of our lives trying to forget that nightmare.
Now, you ask us to revisit it?
For some reason, you can still buy cables on Amazon. Probably some salvage place trying to cash out their inventory
https://www.amazon.com/Accessories-TOKEN-RING-DATA-Cable/dp/B009NAB3L8
I learnt today that the token ring cabling that I was exposed to (TAE) was not common at all. It turns out that it is more of a German standard.
So I'm now wondering what backhanders were involved in seeing an entire NHS Trust kitted out with the stuff!
https://en.wikipedia.org/wiki/TAE_connector
Not doubting your story - but not familiar with token ring. Just had a very, very quick look at token ring connectors, not sure you can put them in the wrong way round.
But there again, (yes I w**k for the NHS too), thanks to a user I discovered that USB "A" connectors can also be plugged in the wrong way round, and on another occasion - the other end will fit into a RJ45 socket.
Doesn't bloody work, and the users(s) claimed that the checked the cables!
If you don't care about destroying the innards of the plug, you can, in fact, plug in a USB A cable the wrong way around.
Had an eMachine with all of *TWO* USB 1.0 A connectors on the bloody thing; one for the mouse on the back, and one on the front. The front was destroyed by an end user applying brute force and bloody ignorance to it. Fortuntely, I had a spare 4 port card that corrected that problem.
'never obsolete' my pale furry arse...
Thankfully, my only exposure to token ring was one that used type 3 cabling.
the other end will fit into a RJ45 socket
Not so hard to do. Most RJ45 ports on the backs of computers are just above a stack of USB ports, in line. With width of a RJ45 port is the same as a USB port (USB could've been made a fraction of a mm wider and stopped that!). The insertion force is comparable, especially when you plug in a lot of cables on various machines. And in most cases the ports are at the back of the machine and barely visible at best, often not visible at all to the non-contortionist. I've often felt for a USB plug then tried plugging in 'above' it to find the plug feels like it is going in OK, only the peripheral doesn't work. Grabbing a readily available mirror (visually similar to a CD/DVD ;) ) shows me what went wrong.
It's made even worse now that plugs and sockets are all quite different (eg used to be a 9 pin D could be serial, or video, or..... but a PS/2 socket is keyboard or mouse, USB, network, power, monitor (slight issue with DVI having 2 main plug standards) etc are all generally quite obviously different. I usually tell people "if it fits in the socket easily, it's fine' - which sometimes leads to issues with LAN/USB...
There was no such thing as 100Mb ethernet at the time. Fast ethernet was first available in 1995 When Token ring (1984) came out, there was thicknet (10base5) and thinnet (10base2) in the ethernet world. Both of which had a much lower availablity rate <40% than token ring's >80%. It wasn't until 10BaseT came out that ethernet was faster than token ring.
I worked at 3Com. 100Mb Ethernet was certainly coming as we were trying to ship 16Mbit Token Ring over twisted pair.
What an f'ing disaster that was! While the Ethernet boys had carefully designed their waveforms to travel over Cat3 and later Cat5 cable, with minimum radiation, the Token Ring problem was that if you low pass filtered the waveform, the jitter blew out of the tolerance band. The stuff worked, but only just.
And the cost (thanks to licensing fees for the MAC firmware) was 3x that of 10BASE-T.
Not sorry to see the end of that.
In Spain it is about 50/50 as to whether neutral or earth is used but the fun starts on a lot of properties where no one has bothered with an earth spike.
Earth is just a random connection to the plumbing so you can get a warm buzzy feeling when leaning against a stainless kitchen sink and someone turns a light or an appliance on.
I once delivered a course for PAT testers, and discussed Earth wiring having to go to ground somewhere.
The (basement) room I was in had very visible earth connectors to some nice copper piping rising from the floor, which looked quite reasonable until I looked up a little and saw the signs "Property of Briitsh Gas"....
....hence the obvious icon
Gas needs to mix in air for a spark to result in combustion and explosion.
The copper pipes need earthing too as the gas mains would likely be plastic, gas flowing through the pipes causes static which could spark from the metal pipes if not earthed.
You should know that if your delivering a PAT course.
Good! The metal gas pipes should be main bonded. That doesn't mean that it was being used as an earth spike though. Some installations such as a TT system use a local earth spike but not all do. In a TN-S or TN-C system it is provided as a conductor in the cable supplying electricity to the building.
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When I got my place, it had gas but no central heating. The guy came in, installed the heater, then said the gas was shut off. He produced a safety card that SWLEC had helpfully left behind.
"Gas shut off as testing discovered a voltage across the gas meter".
I was getting a pixie-wrangler in anyway as the main fuse board was about 40 years old, so it was just one more thing for that guy to do, but I was very glad I was moving in in spring, not December.
A lot of older houses in the US don't have grounded receptacles - it wasn't required by code and everything you plugged in back in the "old days" had two "prongs". The ugly part is where you have receptacles that have three prongs, but there isn't any ground - someone has remodeled and they couldn't find the old style two prong receptacles in stores anymore so it looks like a grounded outlet but isn't.
My house dates from around 1950 and the owners before me finished the basement, and left me with three prong receptacles without a ground. I don't know if they ran the electrical and were cheap, or if those runs predated them or not. There isn't any way to rewrite them to include a ground without tearing off all the drywall. I can see the electrical cords are stapled to the studs in the one area of the basement that isn't finished, so I assume that was done everywhere and thus can't use the existing wiring to pull new wiring. So I just live with it.
I have my computer in that finished basement, on a UPS that has a permanent warning light on the back about an improper ground, but it hasn't ever caused any problems for me. There ARE grounds for the direct wired HVAC/furnace and the outlet serving the washer/dryer, so at least the places where it really matters someone got it right!
Many switch-mode PSUs misbehave if there isn't a functional ground. There's always a lot more conducted emissions and sometimes "interesting" symptoms - eg touchscreens can go totally haywire, not to mention RAM corruption and radio interference.
Worse, a fault inside those PSUs that brought the case live would remain undetected until the user received the electric shock. Possibly fatal.
Run a ground wire. It's cheap and might save your life.
"Many switch-mode PSUs misbehave if there isn't a functional ground. There's always a lot more conducted emissions and sometimes "interesting" symptoms - eg touchscreens can go totally haywire, not to mention RAM corruption and radio interference."
I was called to a conference room where a laptop was being used for an AV presentation. There was a loud, annoying hum in the audio that would worsen/get slightly better if you moved the AV and power supply cables. I noticed that the guy was using a 2-wire Dell power supply on his laptop. Having a moment of inspiration, I found one with a 3-prong, grounded plug and connected it. Instantly the hum went away.
Neutral is tied to earth at the local substation,
the actual voltage measured at a socket will see several volts imposed on the Neutral to earth measurement, this is due to the capacitance of the cabling.
Neutral & live can actually be transposed........
they do it all the time in 3rd world countries.. it's called a 2 pin plug.......
who knows which way round your gonna get that plug......., hence the 3 pin plug/socket in the UK & other civilized continues, it GUARANTEES which side the live is wired....
France has both 2-pin and 3-pin plugs/sockets. The pins on the 16A 3-pin are thicker, so that they shouldn't fit into a 2-pin non-earthed socket. The sockets have no guaranteed position for live and neutral, and some 3-pin dual sockets and adapters are internally wired in such a way that one of the pair will have live on the left, and the other will have live on the right. IIRC 3-contact plugs can be inserted into German earthed sockets either way round, there's no key.
2 prong 'Edison' jacks that are keyed are properly called NEMA 1-15, and IIRC, you can't buy them new anymore for wall installation. (they are used for 2 wire extension cords, though.)
the 'standard' outlet is a NEMA 5-15, which is good for circuits up to 15 amps. 20 amp outlets use a 5-20, which has a 't' shaped neutral line to accept either a 15 amp plug or a 20 amp plug which has the neutral line rotated 90 degrees to keep numpties from plugging a 20 amp device into a 10-15 amp circuit. :)
Other countries have rather important differences though. In those countries the 2 pin plug is not fused because they don't use ring mains. The consumer unit protects the cable too.
In the UK we use a ring mains where the current limit on the 32A ring is higher than the 13A cable so the cable requires a fuse to protect it from an overload that is high enough to set fire to the cable but not trip the MCB.
The potential difference between earth and neutral is 0V, and ~240V between live and either earth or neutral.
If you wire the fuse on the live and it blows it blocks any current flowing into the cable and appliance.
If you wire the fuse on the neutral and it blows then you can still have a potential difference of 240V between live and earth, or any other route to earth (such as you touching a faulty appliance).
So on a fused appliance it's rather important to get them the right way around even if it normally works.
Neutral is tied to earth at the local substation,
Depends on your locale. If you are off a center tapped transformer (think 230V/460V or US 120V/240V split phase systems) the neutral is bonded to the transformer center tap, and that could be a pad or pole mount transformer right outside your flat or a bit up the street. Those can be all kinds of fun if the neutral breaks, as you still have 460V/240V on the outer legs but 230V/120V appliances could be seeing anywhere from 0V to 460V/240V (!) randomly.
Bonding at the substation would waste a lot of copper for no good reason on such systems...
who knows which way round your gonna get that plug......., hence the 3 pin plug/socket in the UK & other civilized continues, it GUARANTEES which side the live is wired....
I think you need to read more of these topics here! There is guarantee... just an indicated location where the live should be, definitely no guarantee. Which is why I tend to operate on the "trust nobody else's wiring" and test the connections first as this saves a lot of time, electrocutions and quickly identifying basic connection issues often indicates the quality of the rest of the wiring.
Printers are the stupidest devices on earth , if they arnt picking one of their 1000 excuses to not print at all , then they are spewing out pages with one line of garbage across the top with a blase "this is what you asked for" kind of attitude , totally unwilling to concede that its unlikely you asked for an infinite number of ruined sheets of A4 and maybe they should stop.
Often the pig headed bastards will resume chomping paper after you've off and on agained them.
HP used to be great at handling odd paper sizes. Used an HP5si for about 20 years. I don't know how many times I sent it a datasheet formatted for A4 paper. Every time I walked over to see the "load A4 tray1" message I just had to hit the enter button on the printer and it would ask "press enter to print on plain letter".
I miss that 5si, but it eventually started eating more paper than it printed. Even the maintenance kits didn't fix it. Plus some sensors started to die...
(Yes, I know A4 is not a strange paper size in the rest of the world)
Often the pig headed bastards will resume chomping paper after you've off and on agained them.
There are usually multiple print queues (spoolers)... in place and in some printing topologies there can be three, but there are often just the two.
Three: Local computer performing the printing, print server that spools the job to the printer and the printer itself.
Two: local computer performing the printing and the printer itself.
Technically there can be more but that's just sadistic.
In more extreme situations it requires that the Windows computer's print spooler service is stopped, the jobs manually deleted, and then the print spooler sevice restarted. On the odd occasion this has to be performed both on the local printing computer as well as a network print server.
Worst I've seen was at w**k - an ERP system with its own internal print queues, which then "print" to an external print queue, which then (for some printers) goes to a pull-print system. Had a problem where the ERP system would claim the printing was successful, but no printing occurred. So which of the queues has the problem?
We changed house at the end of 2017. The previous owner of our new house was - apparently - an engineer, and had a (very) high opinion of himself. He even bragged about having done all the electrical stuff himself. When we moved in, we discovered a few quirks that we had not noticed before, notably a slight buzzing sound in the ceiling of the entry hallway. We didn't make much of it at the time, it wasn't loud enough to be annoying.
Some time in 2018 we discovered that the electric heaters in one room were defective and needed replacing (not something you notice when visiting in the summer). So we shopped around for replacements and found something to our liking, which we got installed in August. When the installer came, he asked to look at the electrical cabinet. I showed it to him and, on opening the panel, I saw his expression change. He looked at me and said "Sir, I cannot install your heaters with this mess. I'm going to have to redo your panel entirely."
He explained carefully and clearly why the existing installation was not only defective and obsolete, but could very well be source of serious trouble (ie a fire). I obviously gave him permission to do everything he thought necessary.
Once everything was cleared up and the heaters installed, the buzzing had disappeared in the entry hallway.
It would appear that the previous owner was less competent than he thought.
I sympathise, having just bought a house (here in the USA) and encountered such diverse horrors as
-external sockets not weatherproofed, with no GFCI [ground fault] protection, just a short arm's reach from a hot-tub,
-sockets in a built-in desk that were wired by the simple expedient of cutting a hole in the plasterboard, ripping out the wires from the existing wall socket and then stuffing them straight into the desk socket, unprotected,
-sockets in a barn that had live/neutral reversed, open grounds, and about 35A worth of load on a 15A breaker,
-30-year-old recessed light fittings so full of mouse droppings, wasps' nests, sawdust and fluff that it's a wonder they didn't spontaneously flame out.
*shudder*
I've had something similar happen when I bought my house. As I intended to swap the gas cooker for electric appliances, the builder's electrician guy prepared the wall sockets (or so I though) and plugged my new electric oven and induction hob. I had then a certified gas technician come to check on the gas pipes and close the one that originally fed the cooker. Fortunately, he was also a certified electric inspector because, when looking at the hob's installation, he shuddered in disbelief. Apparently, the 7200W hob was connected to the wall socket using a poundland kind of plug, instead of being directly connected to a junction box. He told me the plug would probably have quickly burnt and might have caused a major incident. So I asked him redo the wiring and never had a problem since (12 years ago). Phew...
(And if commentards know the rules that apply elsewhere, please feel free to educate us.)
My current understanding of NZ law is that it's perfectly legal for you to make changes to your house, but a tennant must always get permission from the landlord (even if they got the work done by a professional and certified). Some of the smart-meter installers could be in for headaches if anyone ever checked as it's likely the tennant requested the meter NOT the owner, and without the owner's consent.
However, if any mods you (or a tennant) make cause issues, your insurance is not required to pay out (having certification is another matter of course). And being the wonderful, helpful, always civicly(sp)-minded people insurers are, you also need to consider that any fires or other issues with your house may not get fair payment if the insurer has a chance of arguing it may've been caused by that or other bad wiring.
When buying a house, it's not unheard of for people to get a 'building report' done on the overall state of the structure, including electrical, plumbing and structural issues (and whether extensions/sheds/garages etc all have their proper council paperwork). Getting fairly common today even. Your mods may not be illegal, but they may hit you in the pocket significantly if it comes time to sell.
(Not a lawyer, RE agent, insurer or council employee, and never played on on TV either)
"house, but a tennant must always"David? Possibly enjoying an Extra?
The price of having been a Dr Who fan and him being one of the two better actors in the role. His name is of course allowed in my spell check, and "ten nant" is closer to how it's said in Noo Zeelundish than "ten ant" or "te nant" :)
(OOI, did the decline continue as it was during the end of the Matt Smith era/that other fella, or did it get even worse?)
It ended with some woman who thinks she's in a Victoria Wood skit pretending to be the doctor.
What a terrible thing... I am glad I watched only a few of the episodes with the guy who followed Matt Smith before quitting and finding the old stuff from William Hartnell. I'd rather watch a re-creation episode with a few still pictures and poor audio with unreadable subtitles (several generations of VHS copies) than the more modern stuff. Then again, I am watching the Sylvestor McCoy/Mel episodes at present...
In my student days, after a few months of ignoring an intermittent buzzing noise from a wall socket, I unplugged the 4-gang that was in it to discover a millimetre-deep trench of blackened metal carved out of the pin.
Nothing caught fire, the fuses never tripped, but damn did that teach me to not ignore buzzing sounds where the power's running.
Back in the 1980's, I bought a house in New Mexico. Building codes back there and then were about like a third world country, if that good. The service entrance (where the power comes into the house) was supposed to have a pipe coming out of the breaker box and going through the eave of the house to a weatherhead with the 2 hot and 1 ground wires coming out of it and connected to the wires from the electric company, with everything insulated and well out of reach. Instead, some cowboy (maybe a real one - it was New Mexico, after all) had bent the pipe down under the eave. What was worse, the ground rose towards the back of the house, so anyone over 4 feet tall could reach up and touch either of the 2 bare, hot wires which could not be switched off locally. It's a miracle nobody was killed by that.
In addition, they used BX cable (armored, flexible cable) outside. BX cable is to be used inside in dry locations ONLY. And this was for a 240 volt, 30 Amp circuit to a dryer. Oh, dear.
First thing I did was replace the entire service entrance to bring it up to code. Then I replaced the BX cable with solid conduit with watertight fittings. Didn't really have all the money to do that right then, but I really didn't want anyone getting killed, so I found the money somehow.
Would not have allowed me to make this mistake. Having an industrial electrical engineer for a father resulted in better knowledge of 16th edition regs than any 10 year old should know.
That and he used to get me to wire any plugs at home and then check them so I'd be safe when older and unsupervised...
On that note... I do need to figure out splicing a 6 or 8 way socket gang into the ring main of the basement (annoyingly not on its own ring as I've just got basement/ground and 1st/2nd floors only)
I was visiting my parents and offered to mow the lawn while I was there. Typical UK electric mower, double insulated two wire with an 2pin inline connector at the mower end. At some stage my father had replaced the inline connector resulting in the male end live. When I pointed it out he just gave a casual 'Oh' and left me to it. These were the days when new appliances came without a fitted mains plug so I made a point of checking any kit he had wired.
I made exactly the same observation when I was about 12 years old. I discovered this the hard way, but obviously pretended to have worked it out by pure thought when I reported it to Mum and Dad. (Didn't want them thinking I was stupid.) I'm now quite a lot older and that's not the only time I nearly wasn't "now quite a lot older". Quite scary, really. Who'd be a parent?
> On that note... I do need to figure out splicing a 6 or 8 way socket gang into the ring main of the basement (annoyingly not on its own ring as I've just got basement/ground and 1st/2nd floors only)
Option 1: Take the 2 cables going into a socket. Extend one (suitable terminal block) to one end of the new sockets and wire the existing socket to the other end of the new sockets. As long as the resulting connections form a circle not a spur or figure of 8 it's fine.
Option 2: Spur off anywhere on the ring into a 13A FCU and then wire the new sockets as a radial off the FCU. Multiple sockets spurred off a ring is not OK but behind a FCU it's fine as it's classed as a new circuit protected by the 13A fuse which means no more than 13A is on the spur.
I opened up the electric shower at a house I'd moved in to and noticed that live and neutral had been connected the wrong way round, so I switched them to the correctly marked terminals. On turning on the power, BANG and the RCD tripped. On closer inspection, the shower had got a live to earth short within the heater/element so whoever had put the shower in had swapped live and neutral over to stop it tripping (making a neutral to earth short instead). To think I'd been showering under this death-trap.
I've also come across a 3 pin plug where the earth wire had not been connected and just left floating around loose inside the plug near to the live pin. Another death trap waiting to kill someone.
... we got a small shipment of Pilot build IBM 5150s. With them came some dot matrix printers (Epson MX-80? I can't remember ... but they were not IBM labeled). My job was to hook them up and to verify that they worked ... somehow my Boss had found out I was into the then fledgling world of micros, and was a member of the Homebrew Computer Club, and he needed them up and running for a class/demonstration by IBM over the following weekend.
Naturally, they came without the necessary printer cables. I read the (very minimal) documentation, and figured out that they needed standard serial cables. So I filled out a stores request, had my Boss sign it, and went back to my office, cables in hand.
The cables didn't work. I walked back to Stores and swapped them for 6 others. Still nothing. I figured it must be a problem with the 5150s (remember, they were Pilot Build), and carried on checking out the software that came with them. About then, a Mentor of mine stopped by to eyeball the new kit. I explained the problem with the printers. He said nothing but grabbed a test light and a cable. A couple pokes, and he dropped the stuff back on my desk.
"Null Modem" he said. "Now lef's go get lunch."
Turned out the entire box of supposed straight serial cables was wired null modem ... Seems that they went into Stores untested when received from the manufacturer. And this was at the Satellite division of Ford, in Palo Alto. I haven't trusted wire at face value ever since.
Went to a customer site to install an IBM 3274, earlier planning had ensured an underfloor 13amp socket was available. As I lifted a floor tile to connect the power lead I was informed a site electrician had to do all electrical work, union rules apparently. Leccy eventually arrived and proceeded to cut off the moulded plug with moulded ring pull on it to then try and install a cheapo bakerlite plug. The 3274 had a heavy duty screened cable which was not an ideal size for a standard 13amp plug but he managed it. I nearly offered to check his wiring but thought better of it, it worked fine anyway.
1) Hired a Part P-certified electrician to fit a 32A Commando connector to the outside of my house. I didn't have any plugs yet (they are a larger variant of the standard building site connector), but he demonstrated it working by plugging a lamp into an adaptor. Signed off.
When the electric kiln and other things that I later wanted to put on this didn't work, I spent weeks taking it apart and getting the electrical diagrams from the kiln manufacturer. It was only when my "commando -> mains" lead would light up an extension lead but wouldn't power anything that I started to get suspicious. A voltmeter read 18v across live/neutral, but 240v across live/earth.
Turned out that there was an incoming live, neutral and earth from the house. The earth was directly connected (correct). The live was connected through the external weatherproof switch (correct). The neutral came out of the house, into the box, into a terminal block designed for it. And then there was a short piece of blue cable to go from that terminal block to the switch. Except he'd put the incoming into one slot of the terminal block, and the outgoing short cable into another slot... so there was no actual neutral connection whatsoever.
Given that I had the certificate, and the guy was an idiot anyway, I just turn off the fusebox, rewired it, and turned it back on. Worked fine ever since.
2) Once had a room in a workplace that would fuse all the time and trip the RCD. Couldn't get to the bottom of it. Turned out to be pseudo-related to the timings of a fan heater being used. Was just about to condemn it, when I had an idea. Yes... fan heater went into an extension lead, extension lead wasn't overloaded... but did have live and neutral reversed. Switched them back, and never had a problem since.
3) Massive electrical blowout, UPS goes mad and just hard-shuts-down. Does it three/four times. Related to a catering hot-serving thing being used. Turned out that the lights for the servery used one plug, and the heater another. Also turned out that they were plugging them into two different wall sockets. Wouldn't have been an issue. Well, not if those two wall sockets had been on the same phase, anyway.
4) Moved into a new house. Put hand under floorboards when trying to put in some network cable, came back with a bundle of open-ended live twin-and-earth that fed nothing and had just been lying bare under the floorboards. Very lucky not to be dead. The next week, I was inside the under-stairs cupboard, there was a metal-backbox on the wall, with a faceplate. Thought that would be a good place to pinch some power for something low-power (a clock or something, I can't remember). Took off faceplate to reveal... a bare, live, twin-and-earth cable literally touching the metal backbox. Anyone who touched that box would have been dead too.
Learned never to take anything for granted, even if installed by qualified electricians, people you trust, or it comes with a certification. Test everything. Assume nothing. Occam's Razor is that the other guy was a fecking idiot.
Good advice, Trip the Breaker, Test everything & Assume it was wired by a moron until you know better.
Chez Boot still has some interesting wiring from previous incumbents where the feed is not from the expected source and some loose ends under the floor that can't be fixed/extracted until I get around to ripping holes in walls. (ie. a full rewire)
It does surprise me how dumb sparkies can actually survive for so long.
(But try not to - the harm done is all about the path. Finger-to-elbow will make you jump. Left-hand-to-right-hand could be lethal.)
Years back I was taught one simple rule I still live by today. When playing with voltages that could prove fatal, put your left hand in your pocket. That vastly reduces the chances of the 'leccy flowing across your heart.
Very lucky not to be dead... Anyone who touched that box would have been dead too.Good and cautionary tales but you exaggerate a wee bit.
Susans of people get a non-fatal shock from the mains each year. It's shocking but rarely fatal, unless you are a kid or have a heart condition. AC tries to throw you off, it's sticky DC that kills. This is probably an apocryphal / made-up tale but one guy at out factory was killed when some prankster threw him a large charged capacitor.
I was electrocuted once, and I defend the use of that word even though I survived. A BOFH had wired the grounding plate at the back of a monitor to the display. 35,000v, and at high power. I was stuck to the monitor, and I can tell you it is not a nice way to die.
You go into a dream state, but nightmare state is apropos. I dreamt the opening sequence to the 1970s 'Kung Fu' with David Carradine.
I was in bad shape, and when the ambulance medics finally reached me I asked why they'd taken their time. (They'd mentioned they'd stopped to check trophies in the building)
"Ah, well, you were either going to be alive or dead, and either way no need to rush."
I was in the house on my own.
I had my whole arm inside a hole in the floor.
I was adhoc-grounded by a number of things near me - a radiator I was leaning against, the cables I was installing, etc.
I would not have been able to let go, I was not expecting it, and there was nobody to help. And I thought all the upstairs power was off (it was... apart from this rogue cable which I only later figured out the fuse for).
I can assure you from personal, painful experience, that 240v AC will NOT throw you off if you get a good grip on it... it will, just like DC, grab you, hard, and painfully.
If it wasn't for me falling off the work platform forcing me to let go of the junction box (UK style 5 amp type with the exposed screw terminal heads) I'd not be here now.
Previous owner had switched the neutral
It's shocking but rarely fatal, unless you are a kid or have a heart condition. AC tries to throw you off, it's sticky DC that kills.
Oh yes, AC at 240V can quite easily kill you. The trick is not having it go across your heart. If it's going in your right arm and down to your feet there's a good chance it won't kill you. If you're holding earth/neutral with your left hand and live with your right, there's a very good chance you're dead (though CPR can help). While I haven't found decent stats (and am done with searching), one article references 5 deaths in NZ from electrified foil insulation. It's quite safe to assume these were 240V mains.
There was also a news article from 2015 about a man who'd been electrocuted under his house while looking for a leak from his hot water cylinder (also very likely to be 240V with 1 or 2 ~2kw elements). This was a case where an electrician had earlier reversed phase/neutral and an electrical inspector failed to do his job properly where such a fault should've been found (article by a bunch of yahoos : at nz[dot]finance[dot]yahoo[dot]com/news/disciplinary-action-taken-fatal-electrocution-210219851.html - I'd provide a proper link but that recraptha crap stops me - I won't have google JS running so cannot post some links, get it fixed please El Reg!)
As to letting go - no, can confirm that AC can cause you to grip tighter or can mess up nerve impulses so while it may not be causing your muscles to grip, you cannot tell them to release either. It isn't always the case of course, and I believe you are partly correct in that your chances with AC are better.
But overall, I must give you an upvote for the correct use of 'electrocution' which can mean non-fatal incidents :)
A little late but your description is EXACTLY what happened to me on my reply to the same thread. Had hold of a live in my right hand, but fibreglass work platform prevented any nasty tingly feelings (dry vinyl floor, rubber feet on a fibreglass frame)... until I used my left hand to try to manoeuvre the earth wire into place. That's when my world became very slow, very hurty, and very vibratey... I think in retrospect either my head or my eyeball muscles must have been vibrating. I felt EVERY SINGLE one of those sinusoidal voltage spikes. And I would not wish that feeling on my worst enemy, not even a political opponent :( Just thankful that DUMB luck saved my arse
I believe NZ at one time shared the same design of lighting junction box, with the 4 hexagonal shaped pillars with grub screws in them. I had the hexagon shape of the L one etched in the ball of my right thumb for 3 weeks in slightly dead flesh. The left hand fared better because i had a better grip (IE lower resistance connection). I was f*cking lucky.
A pint for both of us coz i need it now remembering that
A pint for both of us coz i need it now remembering that
One back at you by way of apology for stirring the memory. Have another in gratitude that you're here to remember :)
I've deliberately touched electric fences and had dozens of accidental shocks. Tons of static shocks as well, almost none of which I can remember.
I can still remember, and somewhat feel, the pain of the worst mains shock I ever had. It was momentary and thankfully right hand down to knees or waist (I was either sitting or kneeling on the floor). I can barely begin to imagine what it'd feel like to be trapped like that, and I've heard many tales told!
One back at you by way of apology for stirring the memory. Have another in gratitude that you're here to remember :)
Oh cool, my stalky downvoter is back!
Hey Martin, use this as an excuse for another brew! Here, have this one, I'm off to get another for myself...
(And you two, KEEP PUMPING!)
was electrocuted once, and I defend the use of that word even though I survived.
Moved into a new house. Put hand under floorboards when trying to put in some network cable, came back with a bundle of open-ended live twin-and-earth that fed nothing
Sounds familiar. My parents moved into an older house that had once been fitted with overnight storage heaters, but now had a gas boiler. In the roof space I found a long length of 4mm T&E, bare-ended, coming out of the wall and just lying across the boards, connected to nothing. Seeing no point in leaving it like that I cut it with a pair of (fortunately) well-insulated pliers. Large bang, melted plier jaws.
Heading back downstairs to explain why the power had gone off, I realised that it hadn't, and no-one had noticed the 'event'. A check in the fuse box revealed many horrors. A nail in one, in another the correct fuse wire had been used - but looped 3-4 times across the contacts (presumably to make a nice solid connection!).
I spent the rest of the afternoon tracing and disconnecting the storage heater wiring, testng everything, and fixing the fuses.
Finding loose wires that you don't know about in a house or office is the time you pull out a meter and check for tingly stuff leaking out the ends. Absent having a meter to hand, licking the wires to see if they're live is not recommended.
As for creative fusing substitutions the web is rife with risible charts indicating alternatives to commercial cartridge fuses -- the 12mm galvanised bolt is typically rated "2000A slow blow".
A certain friend of mine worked for a company that assembled various electronic bits in the late '70s; back in the day, most of the workforce was required to use wrist straps, because there was little development in ESD protection back then. Fine. Well, that company was expanding and required a new warehouse with raised tiled floors for their affairs.
Cue Sparky the 1st hired as contractor.
This genius managed to mix the ATMOSPHERICAL DISCHARGE ground, with the WRIST STRAPS ground.
On the first LIGHTNING STORM, the entire workforce would recreate Benjamin Franklin's experiment with keys and kites. He managed to find it out, and saved the lives of 90+ workers, 1 week prior to opening. That dude was fired, and was pretty short of being arrested for criminal neglect.
He told me he changed skin color at least 3 times when he got wind of this.... from Pale White, to Cyanotic Blue, to Beet Red...
He managed to find it out, and saved the lives of 90+ workers, 1 week prior to opening.
At first reading I took the "he" to be the sparky involved and thus must ask why he was fired? Mistakes happen, testing and inspecting your work afterwards (and even getting another pair of eyes in) is a normal practice.
If the "he" is your friend and the sparky believe he'd completed the job to a suitable standard, then yes - firing may've been appropriate (though a practical demonstration with the sparky as the test subject may've been a much more, shall we say, illuminating educational aid).
That said, having some first-hand experience with what lightning can do and the interesting pathways it can take, I'd strongly recommend against any workers being tethered to an earth in any sense, that's just asking for fatalities!
(I've seen lightning strike equidistant between arrestors and other earthed items (only a few metres apart) - like the many of the yoof of today it seeks to cause mayhem but would prefer to avoid being arrested in the process!)
[Icon - I should leave before my shocking wit leads me to get arrested and charged...]
1. This friend of mine found the fault and was in charge of fixing it, after reviewing the sparky's job. Sacking was in order for the Contractor. The sparky had in fact done the same mistake in a couple other locations, but the Almighty guarded the Souls of other clients.
2. The wrist strap "grounding" was specifically built for that purpose, so I believe it was designed to tackle those issues... tying it directly to a huge chunk of cooper sunk 10ft. on the ground was not what they had in mind.
2. The wrist strap "grounding" was specifically built for that purpose, so I believe it was designed to tackle those issues... tying it directly to a huge chunk of cooper sunk 10ft. on the ground was not what they had in mind.
Certainly hope so. I recently caught some lightning on film at night, and posed a question to those who viewed it : Consider how much ground area a 100W incandescent bulb lights up. Consider how much ground area is lit to near daylight levels by this one flash of lightning. Just using the visible area and not making assumptions about what is outside the view of the lens, calculate the amount of energy released.
Lightning comes in at high voltages and can find all sorts of interesting pathways to ground. Having an earth strap on your left wrist while working with/handling circuitry with your right hand (as I expect most people would use these things although office bureaucracy could dictate something different) during a storm is inviting disaster as you tend to provide a very convenient ground path.
Of course, if the strap is used to keep you at the same potential as a ground-isolated work area which provides no return path, you may be OK - so long as the isolation can survive unlikely and brief periods of megawatts of power :)
Our council Blantyre office kept on dropping out in '93, intermittently, and this was my responsibility. Our comms boards and muxes were ancient and flaky so swap them out, trial and error. It'd start working, problem solved, then fall over again. Firmware and config on the boards, firmware and config on the multiplexors, line tests on the line. Constant unanswered calls to BT blaming their ISDN line that they said checked out perfectly. And this was 40 staff cut off repeatedly, and thousands of people unable to get housing benefits, it was high profile.
I'd been an electronics guy but this was a council so no electronics kit until the IT director started getting political flak. I got a blank cheque for a decent meter, an oscilloscope and a frequency generator to fault find the line. Nothing, and my job starts looking dubious. Three frigging months of frustration and self-doubt and then I caught and recorded the line fault.
Turns out somebody had shot the overhead ISDN cable, but the pellet only shorted the line in high gusts of wind. Why would someone shoot an overhead cable? Blantyre. I eventually got a written apology from BT that I framed and put on my wall the way over people frame their academic qualifications.
Same job, I was on call out for numerous wrong burglar alarms and that was a pain because 65 mile commute. There was a bug in one of the PIR sensors. Literally a bug, some wee beetle had made it it's home and would return every morning to sleep.
A railway research centre, somewhere in the Midlands, rang me up complaining that my program wouldn't print anything to their matrix printer. Sure enough, when the right commands were issued, nothing at all happened. Was the right cable properly connected both ends? This was strange. Luckily I was familiar with Epsons and asked what lights were on on the front. None. The user helpfully suggested he should try other commands in my program but by my dogged determination paid off when I asked him to check the power cable was properly seated in the back. Silence. "I've found the problem. Thanks for your help." I stopped him putting the phone down until after he'd admitted that there was no power cable.
"I stopped him putting the phone down until after he'd admitted that there was no power cable."
I had the opposite. Support claimed to have spent some time on the phone with the user and eventually passed it to me to go to site. Mains cable in, lights on, no data cable.
My printer crime was worse: 37 years ago I was leaning on the central heating radiator in my student room and I wondered why it felt 'live' and my hand 'buzzed' as I rubbed my hand over it.
Turned out that it was earthed and EVERY mains earthed metal object in the room was live.
Problem turned out to be
1. Earth wire had disconnected in the mains plug feeding a 4 way power outlet strip powerin the entire room.
2. The 1950's Creed teleprinter I was using as the printer on my M6800 based computer generated a lot of mains borne interference from the motor that it used to turn all the cams inside for the mechanical 6 bit decoder.
So I fitted a mains suppression filter and for some bizarre reason I soldered the can of the filter to mains live rather than earth....
Result was all the time the printer was powered from the mains, the room was live.
I fixed the wiring and lived.
Around that time I often picked up live equipment by the live wiring and carefully put it down again.
The most painful was an open chassis Motorola 12 inch CRT monitor where the line output transistor was placed exactly where I put my hand to move it....
I hate the Tech assuption that it's always DNS
when i first started as a PFY our DNS and AD Sites and Services was a Mess (like wouldn't actually work in a DR as it all required bridging connections that only existed in the production PC) and one of my first jobs was to sort it all out.
i have Literally spent years as a junior ,senior and then team lead making sure my DNS was prefect internal and external.
every change documented and done as requested.
old records cleaned regularly.
evertime i worked with a dev or 3rd party or even my own network team and they came in and go it's an issue with your DNS
we always find out it's not my dns examples include
- you need to create 5 c names or the app won't work (not in the documentation)
- 3rd party changing a server on a static vlan to use DHCP without asking permission (wondered why the server stopped responding)
- Host records for server names that were wrong (to be fair this was an upgrade and the new PFY dev was strung up be the ye olde dev who apparently hadn't trusted DNS)
- Failing nics causing systems to faulter.
- the traffic optimiser crashing and taking the whole DMVPN network with it
in the interest of fairness we did have a problem where a Rouge Domain controller making itself the lowest cost for everywhere and that was because we did an upgrade and it thought it was the last one left.
now i've moved over to a PMO/Architect role and had to give it over to some one else. so can't say if it's still in as good shape.
Posting Anonymously as i know some of my co workers read this and maybe upset at me outing them.
This post has been deleted by its author
i have Literally spent years as a junior ,senior and then team lead making sure my DNS was prefect internal and external
All those years you literally spent on your DNS work - was it because the system was such a mess or that you weren't the quickest person around that it literally took years out of your life?
Either way, I've found a small typo can easily turn a perfect config into a prefect config (you probably didn't know the prefects at my school).
we did have a problem where a Rouge Domain controller making itself the lowest cost for everywhere
Bet that made you see red!
It's illegal to do serious house wiring unless you are qualified. Qualifications vary throughout the UK but they are real, and appropriate.
My shitey, wide-boy Cockney brother in law just tried to rewire my parents house, and I told him where he could go. He is not only not qualified, he is not aware of the qualifications. He told me he was qualified to run cables. Any rat is qualified to run cables. Joining them up is another matter.
People die in house fires because some twat decides to swap from joinery to leckie.
Rules only state you have to be "competent" and no matter what the NICEIC, Electric Safe, NAPIT or anyone else says it doesnt require ANY of the following: An apprenticeship, City and Guilds etc
They can help prove competency if you ever went to court, but just because you have the bit of paper doesn't make you competent (and I've cleaned up serious mistakes made by guys who were time served and had 25 years experience, when I did my last city and guilds, 2 of the guys there were senior journeymen, training and supervising apprentices, neither of them got over 28% on an open book multiple choice exam, despite having 2 hours, myself and other guy (former on tools sparky, moved into power plant engineering) finished in 15 minutes and both got north of 95%....2 senior journeymen instead of admitting that they hadn't read the book before the exam or paid any attention during the classes (where the revisions to BS7671 were covered in detail) bleated about "stuff being changed for change's sake" "I put the rights answer down, the computer got it wrong" "I'll keep doing it my way and I don't care what the bloody book says" etc etc etc
Now anything that requires a building warrant or Part P might give you some hassles, but councils are devoid of staff and I've seen stuff that was supposedly inspected by building control and there were serious flaws that were missed, because the inspector walked in "oh this looks nice, turned around and walked out again.......
I had some work done a few years ago which included fitting an extractor fan to an understairs w.c. This involved a mains feed from the lighting circuit, but also a wire from the switched feed to the light, so it would know to come on automatically. Building control looked, and required it to be isolatable, so the builder's tame sparky wired it with a simple switch in line with the mains only. No matter how I tried to explain it, he just couldn't understand why that wasn't enough..
After his mate came round to Part P certify it (thought they could only certify their own work?) and I explained again, we ended up with a three pole switch on a pull cord, plus an RCD on the feed to the room as the existing fuse box didn't have one on the lighting. I didn't trust "professionals" before, but this confirmed my views.
It's plausible to certify other people's work but it's a risk... you're taking responsibility for the installation.
As to the isolator for the fan... they're not actually required, just recommended. However proving the building inspector to be an ass is rarely a good move.
I came home drunk one night and noticed something glowing red by the gate. (there's a transformer on a pole by the gate) Ah! it must be glow worms I drunkenly decided and went to bed. (actually there are no glow worms in this country!) The next day my neighbours told me that they were getting shocks from various appliances. So I went next door with my multimeter to do some tests. I discovered that if I spat on the stone floor my meter would read 100V between the spit and the stove! (this stone house was built in 1900).
Now I remembered the glow worm and went to (investigate?) the gate. There's shire wire* fencing running near the pole and where two wires crossed I found a bit that looked blackened. When I pressed the wires together with my thumb they started to buzz and glow slightly. Oddly I did not get a shock.
The cause was crows using fencing wire to build a nest on top of the transformer. Normality was restored after the linesmen fished it off with a fibre glass pole.
*agricultural wire fencing
I had a a similar failure on, also a Mannesmann Tally matrix printer as it happens, high speed chap with a parallel interface. But in this case it *was* eventually traced to the printer cable after I realised that the errors were the result of one of the data-bits in each print character being always zero. Half the characters (on average, of course!) were correct, the other half were wrong.
I had a similar issue on a Canon LBP laser printer. This was back in the day when that cost over a grand and you got a whopping 128KB or RAM in it. Out of warranty and we started getting odd results when printing. Back then, they still had plain ASCII text printing so printing a "ladder test" showed bit 2 was stuck at 0 and a second cable demonstrated that it was not a cable fault. The PHB was quoted nearly £200 just to have it looked at and a likely estimate of a further £200 to fix it before I'd looked at it. Anyways, a quick look inside and there were a pair of hex buffer chips in the Centronics interface (74 something, 4050 rings a bell) and a quick replacement of a 50p chip and all was well with the world.
Hmm, normally the obligatory RCD should have tripped!
BTW, with normal supply from the energy provider - at least here in Germany- the delivery from external ist T-NCS: Terre -Neutre Combiné-Separeé: 4-conductors (Earth and Neutral Combined) up to the user distribution, here bridge to local earth (Building [basement], water pipes, gas pipes etc.), than 5-conductors after the RCD. This way there should be no real difference between Neutral and Earth concerning noise etc., as long as the RCD didn't trip.
Dr. H. Backhausen
UK on the other hand has the following in its distribution network
TN-S (Terra Neutral - Separate) mainly on older installations, has a live, neutral and earth all the way back to the transformer
TNC-S (Terra Neutral Combined - Separate) - Earth and neutral are the same within the supplier's network but separate within the customer's installation - so basically similar to yourself, but instead we only have single phase rather than 3 phase like many European continental countries so operator side is 2 conductors, household is 3 conductors. Often this has Protective Multiple Earthing aka PME where the supplier "stakes" the earth to neutral along the supply run, which drops the earth loop impedance massively. Badly understood though and many sparks still think you can't use a PME earth with an outbuilding and you have to drive an earth rod instead, you don't but its so pervasive that folk won't be told and won't listen even when you quote the relevant regulation from BS7671....
Ask them to define extraneous conductive part.
99% of UK sparkies run off the osg as if it's the wholly bibble, AND last looked at the actual regs book in the last exam.
I am a sparky but pragmatic. Is it likely to kill someone? No? then i'll do what's easiest. Often that IS making a TT island of the outbuilding, but not when it's 3ft from the house and shares a wall ;)
After moving house, I noticed I got a slight tingle when touching the taps in the shower. I resolved to investigate "when I got around to it." But what prompted me to do so sooner rather than later was that my Sky STB (in the days of analogue satellite - this was an Amstrad box with a built-in POTS modem) would not connect to the dial-up data services. Listening in on the telephone line showed that although it dialled OK and was answered, there was a fairly strong 50Hz background hum (not present when the phone was used standalone).
A multimeter showed that while the mains sockets were all correctly wired inside the house, there was about 50 VAC between mains earth & neutral. Not sure why this should have affected Amstrad's modem, but it did. My PC modem was fine ...
Being a lazy guy wanting a quick fix, I simply connected earth to neutral in a spare plug-top, and plugged that into an unused socket in the kitchen. Both problems instantly solved!
Some years ago working in NY I was walking past our coffee point when the secretary/departmental PA gave a shriek and announced to the world she'd just been electrocuted while moving "a wire".
I took a look as the guilty ones gathered around.
"hmm, let's see: The kettle and the coffee machine are plugged into this half melted white extension cord intended for running three lamp-type devices. So is the fridge You idiots could have killed someone".
"How could we have known the cord would melt?" asked the UK contractors gathering sheepishly around me.
"How could you not?" I demanded. "You all have 'A' level education and above. The cord is clearly labelled as having a maximum capacity of 15 amperes at 110 volts nominal. Let's have a look at all the crap you've plugged in: Kettle - 1 kilowatt. That's around 9 amps right there. Coffee machine: .8 kilowatt for another 7 amps in change. And the pie-ace de resistance? You plugged the bloody fridge into that too. The compressor on that bugger draws 10 amps on it's own. Boil the tea while the fridge door is open and I'm surprised you couldn't smell the technology melting. You can think yourselves luck you didn't kill someone."
Naturally someone argued with me. She pointed out that the coffee machine drew *no* amps around 50% of the time because the thermostat turned it off. I just told the secretary to have this rocket scientist do the cable moving from now on.
Thats what I hate about North American extension leads, they are generally single insulated (banned in the UK - here you need double insulation) and barely cover the amperage rating, try the same in the UK one of the following would likely happen - nothing apart from the cable getting a bit warm or the breaker would trip
Sounds more like a bad connection in the lead causing high impedance, unless the kettle and coffee maker were running solidly for an extended period of time then something is amiss - perhaps the fridge was drawing a good bit more than 10amps, fridges on the whole though only draw that much on first start up, once they've spooled up the amperage draw drops sharply
Heck I;ve seen 2.5Kw kettles (~11amps) supplied in the UK with 0.75mm2 3 core flex (18AWG) (rated 6amps and plug fused at 13amps) and they can get pretty warm in use but they won't melt due to the transient nature of the load (and I tried boiling it 3 or 4 times in a row, worse that happened was the plug got rather warm on the line pin) don't agree with it though, but apparently its ok....I bought a stove top kettle
When I was in college there was a planned power shutdown in the building housing the college radio studios. So we got a gasoline generator, wired up a long extension cord with male plugs on each end, pulled the main breaker for the studio, and plugged one end of the extension cord into the generator and the other end into a convenient wall socket.
It worked perfectly except that the extension cord was warm to the touch. We didn't want it to even cross itself.
Remember, we were college students and just wanted to "get things done" with minimum of hassle. (We also kept the gasoline for the generator in glass jugs which we refilled at the local filling station.)
It's lucky nothing went wrong in a big way.
If there's such a thing as a low-current UK extension cord, it's liable to have a current fuse in the plug that pops if it's overloaded. I once made an extension cord with cable rated 5A, since I happened to have that cable I suppose, and fitted a 5A fuse. We had a slightly amusing incident one cold Christmas when I put an electric heater on it, using 1 kW, which was fine. Until my sister turned the heater up to 3 kW, as I said "No!" loudly but too late; of course the fuse popped. I think I found a spare fuse, or another plug to take one from...
I did similar to myself with a multi-socket extension, which I think had the intended feature that three sockets would only turn on when the fourth was supplying current, so that you could turn on, say, your TV, and the rest of your "home theatre" stuff also switches on. This did have a limit of 1kW, I think, for no clear reason, and a tricky internal fuse, but I was short of an extension and I assumed that it would cope with a 700W domestic microwave oven. It didn't, because such a microwave produces 700W of microwave energy but uses somewhere above 1000W to do it, as it's less than 100 percent efficient. Statements online include "50 percent" and "650W / 1000W". (And there's a motor for the turntable, but that can't be much.) The actual number is in the machine's small print. So again the special fuse popped.
I was setting a office up in Dubai, and as one of the first on the ground I got to see them installing the electrics.
The guy that was doing the installation needed some light, so he took a light fitting down stripped the wires and jammed them into a socket...
When I saw it I gave him a bollocking and told him everything had to be done properly with the correct earth etc.
He pulled the cable out stripped the wires back and shoved the 3 wires into the socket rather than the live and neutral!
When I came round again I gave him another bollocking and said I meant plugs and sockets.
At the same place we had a sub contractor put in our door entry system. It worked, but when I had a reason to poke my head in the roof space I was horrified.
There was power running over cat 5 cables, cables and relays left hanging, wires twisted together. How it didn't stop working / burst into flames cause a rip in the space time continumumum I'll never know.
Another bollocking and it got ripped out and installed properly.
The moral of the story... always watch over the subbies and be prepared to poke your head in the roof / floor space before signing off :)
Could have been worse. My grandmothers house was built in 1921, several years before electrical service was available. When electricity became available, it was wired, with knob and tube wiring (Look it up if you dare!). No ground wires, at all. The line and neutral were both fused. Most rooms only had an exposed ceiling socket for a suspended incandescent bulb. Most of the insulation on the wires had deteriorated to dust, resulting in lots of exposed wires.
Dave
Eh, that's normal for old US houses. Mine was built before electricity (the walls had gas jets for light). Then came knob & tube. Then upgraded to individual wires (no cables) insulated with bitumen (or rubber, now it's just a brittle black material) and fabric, the stuff that when iit gets old all the insulation falls off if you disturb it, and a single neutral cleverly serving several circuits. Connections twisted together and (I think) soldered, wrapped with friction tape. Then Romex (2-wire cable). Only later was work done with plastic sheathed cable with a ground wire (and sometimes surface-mount conduit). Somebody added a ground wire to some of the fixtures, stapled to the woodwork and going who knows where. The K&T is gone now, and the gas pipes disconnected, but everything else I disturb as little as possible, so far so good. I'm banking on the fact that CFL/LED illumination has significantly reduced the load to save me.
Ahh the old VIR cabling (Vulcanised India Rubber) comes under either a cat 1 or cat 2 on an electrical inspection report here - either immediate danger (1) or repair promptly (2) (off the top of my head I forget)
Thats due to the reasons above, best practice is to rip out and replace if you have to any work on that circuit and advise the customer in strongest terms to have the lot rewired (and give that information in writing and get them to sign saying they have refused your advise so when the whole lot goes up in flames / someone gets electrocuted you have the paperwork to prove that you warned them of the hazard and they refused to have the remedial works carried out, as some would otherwise claim you hadn't warned them and you were then to blame for them being harmed (duty of care)
ditto for the old aluminium cabling also (though there was also tinned copper here also, which can be a pain to tell apart from alu, especially in confined spaces with bad light and a house wired in the 60s/70s when both were possible options for the installer)
Of course I looked it up after reading what you wrote. Thank you very many, I’ll never sleep in a 1920 era house again.Really, what cheapskates they were back then too. Nihil sub sole novum, as the viseass said already in ancient times.
In a sense the technology is still widely used around the world today, but quite high and out of reach of most people (look at a nearby power pole - good chance it's done effectively the same way :) )
I wouln't call them 'cheapskates' though. For the lifespan of the insulation, the educational level of the populace (far better trained on practical matters), and one of the biggies - the lack of tools and materials we take for granted today - they did quite a good job. No PVC conduits, no drills with the ease of use we have today, some of the drill bit designs we have today probably weren't around, same for many of the cutting tools (especially electrical). In short, they had a much harder time putting in such cabling and it was the best option available for most people. Especially as, unlike today, buildings weren't made with electrical supply in mind.
(I do have a fun idea with the Wikipedia picture of a textile mill's K&T setup, a handful of H&S busybodies, and some buddies to bet on it... Make a replica of that wall, bring in the H&S types..Gamblers bet on them.. Last H&S to have a heart attack wins the pool... :) I'm all but drooling over those oldtimey lever switches (no idea what the proper name is)! )
I was referring to the knife switches (WARNING : wikipedia link : reality may distort!), which while they may break the circuit they're not what we call 'circuit breakers' here (them being things that at least theoretically automatically turn the power off if a fault occurs).
But thanks for making me get off my butt and re-learn a term I should've known :)
As a student I rented a room in a house where all the wires had been done like that. First clue was a tingling from touching a fridge.The a definite shock from a light switch.
Followed quickly by my getting a cheap tester and seeing it light up when I touched it to stuff.
I just went round and checked everything, then swapped the wires round. And deducted a week or two's rent.
In a (much) earlier post, AFCI breakers were described thus (with a bit of paragraph compression):
The main reason is that the US uses wirenuts. Which are utter shit. Other types of joint tend to fail in safer ways, partly because they're enclosed - a loose screw terminal will overheat but tends to disconnect itself before burning down the building because its inside a box. A lot of modern kit uses sprung terminals which (sans overload) are either a good connection or no connection. The US wiring regs are written assuming fire is the primary danger. AFCIs only protect against fire caused by a bad joint. If you're not using wirenuts then AFCIs don't really do anything much. RCDs will both save your life *and* prevent fire. Definitely fit them.
This is not correct. First, wire nuts properly used are at least as effective and reliable as pressure crimps (which they are a different form of), and in any case are limited in use to connections within approved junction boxes and certain conduit bodies.
Second, the emphasis on avoiding fires results from the controlling authority for the USA's National Electrical Code being the National Fire Protection Association.
Third, the AFCI addresses the problem of zip cord extensions routed under rugs where they gradually degrade, as well as old defective wiring in inaccessible locations, and even new cable subjected to someone's poorly positioned nail.
Fourth, most AFCIs sold are combo types that include GFCI functionality.
Two thoughts. First, I'm somewhat surprised the bloody thing didn't arc and catch fire. The second is when we lived in Tanzania. The receptacles were all three prong but there was a "door" over the ground (earth). If you didn't used a grounded plug, you could not insert it into the receptacle. The door in the ground socket actually moved another door that was in the positive / neutral slots. And that also explained why almost every place we went there were small pieces of wood or wire by the sockets.
So I'm installing a test VOIP Asterisk box in a server room at a business that took over a warehouse. I decide to sit down on a PC box that's on the floor that has its case removed. Who hasn't used an ATX case as an impromptu chair?
The face as the PFY looks at me and can't stop laughing when I scream out in pain and shout that I've just been shocked in the F***ing Ar**hole!!!
Turns out that the building had numerous wiring faults. The ISDN30 ground was actually reading 180V to earth, The PC on the ground was actually connected to the correct earth,I'd been holding the cable from the NTE when I rested my behind!
Same said room standard UK outlets on same wall were on no less than 4 different phases due to their being an onsite generator that was running and not synced with incoming supply. None of them tied to a common PE.
Never lived it down!
A friend of mine moved into a house she just purchased. (in the USA) The house was built in the 1950s and parts of it had two-wire, ungrounded outlets, while parts were 3-wire. She noticed that whenever she tried to use her CRT computer monitor plugged into a grounded outlet in one of the bedrooms, it would instantly trip the circuit breaker. The monitor worked fine on any other outlet, and anything else plugged into the outlet worked, apparently without incident. As I recall, one of those little 3-neon testers showed a bad ground, but nothing else amiss.
I took the plate off to find that someone had decided to replace the 2-wire ungrounded outlets in the room with 3-wire grounded outlets. But they couldn't be bothered to run new cable, so they wired the neutral and grounds together. Which is a code violation, and not the right way to do things, but probably would have been mostly okay if they hadn't mixed up the hot and neutral wires. So the 'hot' pole of the outlet was neutral, and the neutral and ground poles were hot. The monitor apparently had some internal fault that caused a direct short in this configuration.
Aside from the annoyance with the monitor, this was a potentially lethal accident waiting to happen. If someone had plugged in a device with the metal case connected to ground for 'safety', such as an older power drill for example, the case and the user would be electrified. Then all they would need to do is touch a pipe, metal window frame, or something else that really was grounded to suffer electrocution. This is not the first scary thing like this I've seen over the years in older homes, including in my own.
Used sewing machine - given free as "trips RCD"
Took a look at the motor, straight out of the 50s, footpedal same age and what looks to be asbestos inside - double bagged and disposed of promptly....pedal was made of metal and motor speed was controlled by resistance within the pedal, bare wires wound around an asbestos block (similar to an anti flash pad in a fusebox but much much bigger - try bar of soap sized, hence the rapid reassembly and double bagging when I spotted that)
Order new motor and footpedal combo - all works wonderfully
Remove plug from old motor lead and discover some "genius" when they had wired up the new plug hadn't had a clue how to wire it - flex predated harmonisation so red, black, green (and flex harmonisation came in around 1962!) IIRC they had went green to neutral, red to earth and black to live, no wonder it was tripping the RCD, that or it was green to neutral, black to earth and red to live, either way the RCD would have tripped out, but wouldn't have caused any issue on a house wtthout RCDs (in the latter case at least)
Giver had appeared technically competent...just goes to show, never assume anyone has a clue what they are doing
On the plus side, one asbestos death trap footpedal out of the equation
Mannesmann Tally was a big a deal in the world of dot-matrix printers back in the last century.
there is SO much hurt in that one sentence ffs
Mannesmann / dot-matrix printers / last century.
hellfire, I STILL think of the 80's as just a few years back, when in a couple of weeks it will be FORTY years :o(
Many years ago I found myself wandering through Bolivia for the simple reason it was there and I had nowhere else to be. Down that way it's very common for showers to have the heating element in the shower head itself rather than in a separate box on the wall. The open mouse-trap style mains switch inside the shower stall was my first hint that electrical standards were a little bit different different, but when in Rome (or La Paz in this case) do as the Romans do.
The shower was really good. Hot water and lots of that left you feeling refreshed and slightly tingly. Almost spa quality and better than many of the hotels I get to stay in nowadays. Until you tried to turn the shower off. That meant using a nice metal tap and suddenly that slightly refreshing tingling became somewhat invigorating to say the least.
I've vaguely thought that a shower that generates hot water on the inkjet principle would be efficient, just heating the water as it's delivered, probably well programmable for temperature as well. BUT you'd have a lot of electricity inside the shower head or handset. If that's fixable, it's a thought.
My heated shower's on the blink, I should replace it... it has half power and full power, but full is painfully hot and half somehow isn't working any more, it comes out slightly above room temperature and I don't like that either. So I have to switch between the two settings throughout my shower. And apparently it takes around ten seconds for water to pass from shower box to shower head, so I have to anticipate.
Had an Electrican rewire the 19V end of a laptop power cable,only to find it still wasn't working.
On inspection I discovered he'd swapped the polarity over.
"Does polarity matter?" asked the innocent looking man.
I replied, "don't rewire anyone's house until you understand why it's a bad thing..."
Pfft! I owned a '64 Mini Traveller*.
All reversed polarity means is you have to reverse *all* the polarities back to the breakers. Easy peasy, volts up the fingers. Aggleaggleaggle.
Of course, if the polarity is reversed on the drop from the pole pig, life gets a bit more pyrotechnic.
Aggleaggleaggle.
* Positive ground electrics - something to do with corrosion resistance. Wiring accessories like radios was "fun". Also had a genny, so those accessories had better not be too thirsty.
Also had a genny, so those accessories had better not be too thirsty.
At least it was then easy to swap the whole car to -ve earth. Much harder with an alternator with diodes & other electronics, you couldn't just swap the residual magnetism by tapping a wire to the battery briefly.
It was usually easier to flip the car, in a 1964 Mini/Morris almost nothing was polarity-sensitive. Early car radios could sometimes be switched (I remember taking my Dad's old Pye radio and switching it to go in my Mum's Morris Minor) but as -ve-earth-only car radios became more popular in the 1970s there were plenty of magazine articles about how to swap the car to -ve earth. Reverse the starter motor wires, some connection changes on the regulator, and 'flash' the dynamo to change the residual magnetism, that was about it. You might have to swap the heater fan motor wires, if your car had such a luxury. Avoided all the problems with shims, isolating cases, stray wires, etc.
On the other hand, the wiring on those cars is so easy that ripping it all out and re-wiring from scratch isn't really all that difficult. My 1963 Ford Consul Capri GT is now 12V-ve, from 6V+ve. Only took a couple days to build a new wiring harness. Probably didn't hurt that while I was at it, I swapped in a Mazda 13B engine & 5-speed from an RX4 ... That bit took a trifle longer.
Place I used to work occupied the upstairs of a two storey building that had obviously been a single unit originally, before being extended sideways and then eventually split horizontally . There was only the one incoming mains, and one meter for both upstairs and downstairs. This made working out the electric bill with the neighbours "interesting". What was worse was the half dozen or so different fuse boxes spread all over the building, often feeding sockets or lights in the other half or other level! But the icing on the cake was a loose 1.5mm T+E near the meter that, on investigation, linked between two circuits which were otherwise separately fused in different boxes in different locations.. It made isolating the circuits something of a puzzle until I found it. I can only assume that at some point a fuse had blown, but access to the other box wasn't possible, and this was added to get the circuit live again quickly, and never removed.
In another life, when I managed a restaurant, we were having a very slow, boring day, which translates to "clean the store, pull out racks, etc." There were a few damaged ceiling tiles that I decided I'd try to replace. I got out the ladder and poked my head above the drop ceiling and discovered many wonders:
-A huge, old alarm bell. (which I had some fun with by wiring it in place of the little entry chime on our front door, to the chagrin of my assistant manager)
-A lantern style flashlight which was completely rusted out and stuck to part of the ceiling from the battery corroding.
-A torn and destroyed AC/DC T-shirt
-And the prize winner: 2x large neon sign transformers, 12KV and 15KV plugged into power and energized, with the high-tension leads hanging down, bare, almost touching the drop ceiling. Both a fire and electrocution hazard. Apparently in an earlier remodel, some old neon signage was removed by cutting the wires and the transformers left in place. I still have the 15KV one--I made a nice Jacob's ladder out of it for a demonstration once.
Back when I repaired power tools I had a similar issue. A circular saw crossed my bench with the complaint "trips breaker" per SOP I put it on the Sotcher electrical tester and it passed, then I opened the handle and found the fine line between stupid and clever. The power cord had been replaced, badly. The tool was double insulated so it used a two wire cord and the owner had replaced it with a 3 wire cord and since ther were only two terminals he wrapped the end of the ground wire around the hot wire so plugging in the tool created an immediate short to ground. I swapped the cord for the proper two wire part. This was typical of life with the construction trades where things were "fixed" every which way but right.