A pair of thick sparkies were working on thicknet cable. How appropriate. Next decade, they did some twisted pair work.
Seriously, you do not want to make that cable your earth
This week we bring you a shocking incident for a Register reader who was party to an electrical engineer's earthly delights. "Andrew" takes us back to the 1980s, the days of DECNet, DEC Rainbow PCs, and the inevitable VAX or two. Back then, DECnet was a big noise in networking. Originally conceived in the 1970s to connect PDP …
COMMENTS
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Friday 20th May 2022 11:53 GMT Martin an gof
We have a box at home. I don't think anyone else has caught on yet, but next time the eldest fires up his pizza oven...
M.
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Friday 20th May 2022 16:15 GMT heyrick
True, but the comptent are seldom remembered. It's the mind numbingly stupid that chokes the memory.
Had a guy come to fit an immersion heater at home. It's an old farm. Three phase supply, stuff tapped off randomly all over the place. Suffice to say, CPL is useless.
He set up a nice new fusebox with a little trip switch and all, and wanted to wire it into the mains. So he looks at the four wires underneath the master switch and asks "which one is live?". I briefly explain what three phase is, and tell him what wires to connect to. Cupid Stunt only goes and gets it wrong (the two on the left, how hard is that?). Thankfully he was partial to taking smoking breaks ALL the time. So off he went, cigarette in hand (in the house too, I swear if I had a fire extinguisher handy...) so I switch the wires around when he isn't looking. Hook it all up correctly.
Like I said, it's the idiots that stand out and get remembered.
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Friday 20th May 2022 12:51 GMT OldSod
Re: Bee-sting ?
That Wikipedia article captures the essence of vampire taps quite well. I still remember the Teflon drill bit in the installation kit, and taking the risk of drilling into the 10BASE5 cable during the day with a live network to get an install done. If one was not careful, then shorting the shield to the center conductor would disrupt communications.
Of course, there weren't really the many stations on the network in the early days of the Ethernet LAN in our 250-person office. A pair of VAXes (11/785 and an 8550 in a CI-based VAXcluster), a handful of DEC LAT terminal servers, and a few PCs for the folks who needed faster data transfers to/from the VAXes than asynchronous KERMIT file transfers could accomplish. DEC Pathworks/PCSA (Personal Computer Systems Architecture) reduced the mighty VAXes to mere file/print servers for the PCs, and added full DECnet node capabilities to the PCs as well.
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Friday 20th May 2022 23:09 GMT jake
Re: Bee-sting ?
"and
almostguaranteed to start leaking in a few weeks, if not same day."FTFY
Seriously, learn to sweat copper pipe, it's not exactly rocket surgery ... unless you're enlightened and have switched to PEX. Regardless, turning off the water for 15 minutes (if that!) while properly installing a tee is hardly a hardship.
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Saturday 21st May 2022 17:07 GMT Eclectic Man
Re: Bee-sting ?
Umm, my latest water softener (Harveys, a UK version of the previously top of the range Kinetico) has a waste pipe 'vampire' tapped or saddle mounted to a waste pipe behind the 'fridge. Not leaking yet. Do I need to get it looked at by a proper plumber? (Plastic waste pipe, btw.)
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Monday 23rd May 2022 18:13 GMT jake
Re: Bee-sting ?
"There speaks a man who hasn't dealt with a stoptap which hasn't moved for twenty years during which it was painted over four times,"
Discovered and replaced (or installed, in some places) before I moved in. While I was at it, I replaced (nearly[0]) all the copper pipe with PEX, and wired and insulated the place properly.
"and an external stoptap that's been tarmaced over."
Had the City out to fix that one at our house in town[1]. Up here at the Ranch, I didn't make that mistake when I installed the water system.
[0] Shower & bath stub-outs are still copper. Easier that way.
[1] Where do YOU park your in-laws when they visit?
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Friday 20th May 2022 23:27 GMT Anonymous Coward
Re: Bee-sting ?
These are called "saddle valves". They're very easy to install, and almost guaranteed to start leaking in a few years.
I have one that's the exception that hasn't leaked yet. Unlike the drinking water system that it was hooked up to.
After changing the filters a few time I got a leak at the shutoff valve going into the first filter. No problem I thought. Just need to redo the Teflon tape. Took the old tape off and off and off... Turned out the threads on the valve were a different size so the "plumber" had added a lot a Teflon tape till it stopped leaking. I could put the one fitting inside the other with twisting it.
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Saturday 21st May 2022 10:18 GMT Anonymous Coward
Re: Bee-sting ?
A tube of Fernox LS-X "Jointing compound and external leak sealer" is a handy thing for sealing copper compression joint threads. Avoids the danger of over-tightening a recalcitrant weeping joint. The only problem is that a 50ml tube is quite large - and the contents tend to solidify by the time you next need it.
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Saturday 21st May 2022 10:24 GMT Anonymous Coward
Re: Bee-sting ?
Installed a new bath for friends. They decided they wanted the 4" iron main down-pipe changed too. I said that was a job for a professional plumber. I was house-sitting while he did the job. At one point he was unsuccessfully trying to glue his Osma pipe to the modern plastic compression fitting on the bath's drain. When I showed him how to tighten the collar it appeared he had never seen such fittings - which had been in general use for at least 10 years.
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Sunday 22nd May 2022 08:31 GMT Eclectic Man
Re: Bee-sting ?
Reminds me of an aircraft incident report. The 'fitter' had replaced a fuel non-return valve between the fuel tank and an engine. This is to ensure that fuel only travels FROM the tank TO the engine. Anyway, the 'fitter' KNEW that the valve had to go a particular way round, but for some reason simply would not fit, so he filed down the thread on one end of the valve until it did fit, and fudged the other end.
Sadly there was enough fuel in the line between the valve and the engine for take-off, but not much more. It crashed.
Note to fitters: fuel non-return valves are designed with different size threads on each end SO THAT THEY ONLY FIT THE RIGHT WAY ROUND.
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Monday 23rd May 2022 15:28 GMT Alan Brown
Re: Bee-sting ?
Murphy's law states that if an aircraft part can be fitted two ways and one of them is the wrong way, then someone will fit it the wrong way
Murphy's wife's law says Murphy was an optimist
I'm never sure if he took things like the fitter above into account, or the russian who managed to install a g-sensor upside down on a recent proton launcher despite the mounts being explicitly designed to make it impossible to install upside down... (the Proton did the predictable thing and crashed almost as soon as it cleared the tower)
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Sunday 22nd May 2022 11:05 GMT Man inna barrel
Re: Bee-sting ?
I have never used such a connection, but it sounds like it works for multi-drop connections over coax. Instead of cutting cable to length, and terminating with BNC or whatever connectors, you a apply a bee-sting, without cutting the cable. The bee-sting pierces the outer insulation, and makes contact to the inner conductor. There has also got to be some insulation on the stabbing bit, and another bit of conductor, to make connection to the outer braid, without shorting the cable out.
Having described how I think a bee-sting works, I am glad I never used such a beast, and stuck to proper connectors, tee-adaptors, and so on.
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Friday 20th May 2022 20:19 GMT swm
Re: Bee-sting ?
At Xerox we used RG-11U foam cables for our 3MBit ethernet and cable TV taps. The problem was that nothing moved and eventually the tap became disconnected. The taps were designed to be used outside so the wind would move the taps a little and thereby keep the center "stinger" connected.
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Friday 20th May 2022 23:27 GMT jake
Re: Bee-sting ?
I've still got a thicknet link from up here in the office to the small cluster of vaxen down in the machine room/museum/mausoleum/morgue. Seemed silly not to include it when I wired this place, because the walls were open & you never know. A couple years ago the concept was justified when I inherited a DEC Rainbow from a friend :-)
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Friday 20th May 2022 23:38 GMT jake
Re: Bee-sting ?
The unit was always called a vampire tap, yes.
However, I knew quite a few network engineers who called the tap's probe a stinger. I tried to get them to knock it off because we were often discussing three-phase power in the same conversation, but to no avail. Perhaps it's use here is an artifact of this nomenclature?
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Friday 20th May 2022 09:04 GMT Anonymous Coward
Rainbow - Nostalgia
The mention of the DEC Rainbow PC takes me back to my time working for one of the oil & gas operators. I moved to one of their UK HQ offices and got my first hands-on experience with “my own” desktop PC (until then, I had got quite familiar with teletype and VT220 access). The Rainbow could boot to CP/M or the new MS-DOS. Mine has a 10MB HDD and two 5.1/4” floppies and booted to MS-DOS. My main application was Lotus Symphony with which I ran a spreadsheet/database to oversee procurement inspection for North Sea operations (back then my £2m budget was quite a lot of money). I could “email” suppliers by direct access to the telex system (quite common, almost mandatory, for regular suppliers back then). Didn’t see the network in the article, though - the network connection was via RS232 serial.
Someone had planned ahead when setting out the offices and there were more ports than usually needed; printers were also connected into the network so you had the ability to print direct to other offices. It was there I got quite familiar with RS232; my job had nothing to do with IT but support was patchy and I found my Psion II, with an RS232 cable, was great for troubleshooting connection issues. For example, printer settings were far from standardised and the easiest way to find out how a printer was set up was to plug in the Psion and run a small script that ran through the various combinations - the one(s) that actually printed out were the ones in use…
The DEC Rainbow wasn’t the fastest PC of the day, but it did what was needed at the time. Fond memories :)
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Wednesday 20th July 2022 15:59 GMT Anonymous Coward
Re: Rainbow - Nostalgia
Nah, a lack of moral fibre is a requirement to be a politician. When you go to register as a candidate they show you a series of horribly disgusting pictures and if you say "yuck" to any of them your application is rejected.
If you say "Done that, did that, doing that tonight, who HASN'T done that, ect" you're fast tracked to national office.
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Friday 20th May 2022 09:16 GMT Barry Rueger
Re: Rainbow - Nostalgia
For example, printer settings were far from standardised and the easiest way to find out how a printer was set up....
At the risk of sound all old-farty, there few greater delights for me than installing Linux on a machine and having it just find and install all of the printers on our network. Dear God, the HOURS spent battling with printer drivers in the Good Old Days.....
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Friday 20th May 2022 14:55 GMT Anonymous Coward
Re: Rainbow - Nostalgia
I recall, in 1995, being provided with a Mac as my desktop in a new job*. The company had a mix of Mac and Win 3.11 desktops, plus a smattering of Sparc. A Canon colour printer/copier was installed in the central print room and certain engineers were given access. Unfortunately, it only worked with the Win PCs - the driver for Apple desktops just generated an error. Ever the tinkerer (when hacker wasn't a derogatory term) I opened the driver in a text editor and changed a couple of characters. I don't remember what but I think I managed top track down the error code and spot something - that was a long time ago! I saved the file and it worked on my Mac - print room asked for a copy and sent it out to other users with a Mac.
You have to have lived through the days when every program needed it's own printer drivers, and each printer had its own needs.
*A year later, the company replaced every desktop (excluding Sparc beasts) with a Win95 desktop or laptop - spent $millions worldwide on that! I got a Lenovo laptop - sad when I had to hand it back when reassigned to a sub-contractor.
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Friday 20th May 2022 16:24 GMT heyrick
Re: Rainbow - Nostalgia
Oh, yes, printer drivers. Or how to lose your mind trying to get the bloody thing to understand the difference between £ and #. I've actually seen printed listings in books that had £ where a # should have been.
But all of those frustrations are nothing compared to the utter trauma of sorting out IRQ conflicts in (E)ISA cards. Not to mention some serious weirdness relating to COM port interrupts and why mice and modems had to be on specific ports or it would all blow up. Grrr!
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Friday 20th May 2022 09:12 GMT Barry Rueger
Much applause for this one...
Ah, the 1980s. Simpler times. These days all we need to worry about is Bob in Sales insisting he be moved from the Wi-Fi access point for fear of having his brain cooked while still spending much of his day with a smartphone pressed to his ear.
Thank you for that. Just thank you.
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Friday 20th May 2022 11:29 GMT MiguelC
Re: Much applause for this one...
Unfortunately, it's not only Bob in Sales.... my previous boss, an ex-techie on top of all, used to routinely unplug the wi-fi AP over his head because he "didn't want radiation around him like that". I tried reasoning with him but utterly failed, as expected. So I used to just plug it again when he wasn't around.
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Friday 20th May 2022 13:20 GMT SW10
Re: The illusionist on a train
I once used my Blackberry to take a call on the train and an older guy standing a couple of metres from me practically fell to the ground, groaning and holding his head.
His wife* looked daggers at me, then hissed at me that her husband suffered instand migraines when a mobile phone was active.
The call was over in seconds anyway, and as I slipped the phone back into my pocket, the guy miraculously recovered. As the smug owner of this early "always-connected" device I wanted to call him out, but realised that being the only person who had seen through the illusionist's trick was somehow more satisfying.
* I did feel sorry for her, obviously fiercely loyal and I wondered what other bullshit she had to put up with
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Monday 23rd May 2022 05:58 GMT gnasher729
Re: The illusionist on a train
Psychosomatic effects are real. Knowing that WiFi is turned on can cause migraine in some people, and it is a real migraine, not acting. It goes away if they think WiFi is turned off.
Whether WiFi is actually turned on or not has no effect. Only their perception.
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Friday 20th May 2022 16:08 GMT Throatwarbler Mangrove
Re: Much applause for this one...
I had a senior network engineer who reported to me who refused to use a cell phone without a headset and would go to enormous lengths to avoid it, such as firing up a VOIP app on his laptop in preference to cell phone use. His reasons, as one might expect, were spurious and illogical, so I didn't bother arguing.
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Monday 23rd May 2022 15:49 GMT Anonymous Coward
Re: Much applause for this one...
Back in the flipphone days I noticed that I would get headaches on the side of my head where the phone was used, after an hour or so of use. I started to use a headset, and the headaches stopped.
I did too, but found it was because I used my neck muscles to clamp the phone to my ear while I did other things. Landlines used to give me a headache for the same reason. Discovered that when I started using speaker or an earpiece it went away.
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Friday 20th May 2022 16:27 GMT heyrick
Re: Much applause for this one...
There's a nice woman at work who tells me she is sensitive to radio waves. If she is near something that emits waves, she can feel her head heating up. Etc etc. No, she doesn't have a mobile phone.
Because she is otherwise quite a pleasant person and good to work with (not a jerk), I didn't have the heart to point out that the box on the wall beside her was the staff room access point.
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Friday 20th May 2022 09:47 GMT My-Handle
Re: Sparkies...
I don't think we've had any here who've caused major damage. But we have had a few "special" cases. Like one electrician unplugging some major networking gear (severing the site's network in two) so he could plug in his drill. Or mis-wiring a fire alarm, setting off the entire system and incurring a £1k fine from the fire department for an instant-response false alarm
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Friday 20th May 2022 14:00 GMT Phil O'Sophical
Re: Sparkies...
Not just sparkies. Many years ago a plumber was working in a shopping centre near us. He set his blowtorch down carelessly, and set fire to a case of tea. To try & put it out he went looking for a fire extinguisher, by the time he returned the warehouse was on fire, and when the fire brigade arrived they couldn't save the rest of the centre. There was some news footage of a car dealer being interviewed in front of the main doors about the new cars on display in the main mall and, just as the interviewer asked if he thought the cars could be retrieved safely, the roof of the centre fell in. The dealer just grimaced and said something like "I don't think so".
Something like 17 million quid damage, and the plumber's liability insurance topped out at 1m... They never rebuilt.
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Friday 20th May 2022 10:28 GMT Sam not the Viking
Re: Sparkies...
Setting the scene: New major power station in the course of construction. Four generators and the station was being completed in two halves 'A' and 'B'. Regular meetings with all the contractors to check progress etc. In general, things would be late, but unusually, this site was going pretty much to plan.
These meetings were held on the top floor of the control centre, located centrally, with a view over the entire site.
"How is the 'A' cabling coming on, Bob?" (These are big cables, and there's a lot of them.)
Bob glances out of the window, where he can actually see the progress.
"No problems, everything is in hand."
Well, the job moves on and over the months, various bits near completion.
"What about the cabling, Bob."
Quick glance out of the window.
"No problems, everything is in hand. We're awaiting the cable trenches."
"Bob, I think you're looking out of the wrong window."
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Friday 20th May 2022 10:50 GMT notyetanotherid
Re: Sparkies...
Was having the kitchen re-done, everything stripped back to bare brick. Was just after Part P came in so I could no longer legally do the electrics myself. The sparkies nailed the capping through the cables. Fortunately, I spotted this just before the plasterer arrived to start re-plastering the walls...
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Friday 20th May 2022 12:01 GMT Martin an gof
Re: Sparkies...
You can do the electrics yourself under Part P. In fact there are quite a lot of "minor" jobs you can do without any hassle, but the bigger jobs (there are clear definitions) do need to be inspected and signed-off by someone who is qualified / registered / insured to do so.
I've just wired an entire new-build house myself (with help from a couple of teenagers), and managed to find a friendly electrician who was willing to pop around a couple of times at key points in the job, and then spend a whole day on site taking it all apart and testing everything.
It probably helped that I used to be Part-P registered myself, but from the point of view of the regulations I'm now no more qualified than Joe Public.
M.
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Friday 20th May 2022 12:56 GMT notyetanotherid
Re: Sparkies...
@Martin an gof,
> You can do the electrics yourself under Part P
I know that you can, it was just that immediately after Part P came into force (I started the project a month too late), I could not find anyone willing to certify an installation that they had not done themselves (kitchen electrics require certifying). Indeed, IIRC, at the time NICEIC was specifically recommending their members not to certify anyone else's work. I even half-considered becoming Part P registered just to fill that gap in the market....
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Friday 20th May 2022 16:21 GMT adam 40
Re: Sparkies...
One installed a new fusebox in my house and half was RCD. An old house with 1970's PVC wiring.
The RCD kept tripping so he blamed my old wiring and moved the ccts over to the other side.
Some time later I wanted to put stuff on teh RCD. Virtually anything you plugged into it would trip it.
I bought a professional mains tester - the leakage was all fine.
Turned out that he had installed the RCD sense wires the wrong way around! D'oh! Wires swapped over, it all works a treat. So - code or not - if you want it done properly, do it yourself.
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Saturday 21st May 2022 07:53 GMT Martin an gof
Re: Sparkies...
IIRC, at the time NICEIC was specifically recommending their members not to certify anyone else's work
I was among the first to register under Part P with NICEIC and I don't recall any such advice - other than the obvious about not just handing out certificates without thoroughly checking work - and indeed I did a few such jobs myself. The key is to be certain that you have seen everything. Giving advice and leaving the grunt work (chasing walls in particular) to someone else saves a lot of time and effort on the electrician's part (and the first thing one-man-bands often do is take on a "boy" to do that work) and cost on the householder's part.
However, finding an electrician who is willing to do that is absolutely a big problem. In theory the council should be able to provide a qualified building inspector who should be more amenable, but in practice this is just as difficult.
I considered re-registering for Part-P myself before the job, but apart from the cost (insurance, membership of the registering organisation), they are no longer willing - as they were in the early days - to register you based on previous work and an understanding of "the regs" (in my case, a C&G in 2381); they now require a couple of specific bits of paper that cost hundreds of pounds to study for and take a minimum of several months.
The builder's own electrician would only certify my work if he could have been on-site with me every day I worked, which was a bit of a problem as I was intending to do most of the work in evenings and at weekends and it wouldn't have cost any less than just letting him do the whole job himself, but fortunately I found another one who only wanted to do a pre-start visit, a couple of visits during work and a day or so on final checks. It ended up costing less than taking the courses and registering with one of the bodies would have done, and certainly saved a lot of hassle and time doing so, though having Part-P would have been handy in the year following as I "finished off".
If you can't find a friendly electrician there is a surprising amount of work you can do yourself without needing certification. Without looking up the full list it boils down to anything that isn't "providing a new circuit" (so you can add a spur DIY) and is not in a hazardous place - bathrooms and outdoors mainly I think, though you are allowed to replace like-for-like in such areas, such as swapping an old or broken switch or light fitting.
<disclaimer>
As ever though, don't take my word as gospel. The regulations do change from time to time. Make sure you know exactly what is required before starting any work, and if in any doubt, get a professional in.
</disclaimer>
M.
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Saturday 21st May 2022 20:59 GMT Anonymous Coward
Re: Sparkies...
There was, and still is, the option of just notifying the local Building Control dept. Tell them when you're done and if they want it certifying, technically it's up to them if you don't provide the certs. My local BC used to charge an extra £75 in these cases to pay for them getting a spark in.
And you don't need to be a member of any of the competent persons
schemesscams. Just provide a set of certificates for the work and they are likely to just accept them without quibbling. In my case, I'd retort that they need to put up an expert with a higher level of qualification than I have if they want to argue - so where have you got a Level 7 sparky hiding ? -
Sunday 22nd May 2022 23:53 GMT Ace2
Re: Sparkies...
Why would providing a new circuit be any more complex? If anything it’s simpler and reduces the already tiny chance of overloading something. If I want just one more outlet somewhere, I can assur that it’s overloading an existing circuit.
I’ve run my own circuits for a chest freezer, room AC unit, and printer. The stupid printer used to make all of the room lights flicker when it heated the fuser. No options anywhere to disable fast start, or whatever. Now it’s on its own circuit and doesn’t bother anyone.
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Tuesday 24th May 2022 13:12 GMT Martin an gof
Re: Sparkies...
I realise this is a few days later, but it's worth answering.
Firstly, I'm talking about the UK which has some, shall we say, unique ways of doing things.
If your printer makes your lights flicker then there is something else at fault, though I realise that in some parts of the world it's common to have a single supply to each room which then feeds sockets and lights.
Assuming the latter in your case, please understand that this is not normal practice in the UK. It's not unheard of, but due to the sub-fusing requirement (sockets circuits are 16A, 20A or 32A while lights are 6A or 10A) and often the difficulty of routing the cable anyway, it is very rarely done. Most often seen in (say) a garage, where you can run a 16A circuit to a socket for the freezer and then fuse it down to 3A for the garage light.
Adding a spur to an existing sockets circuit is allowed as it should be a "better" solution than using a socket-doubler or extension lead. Only one additional outlet (that is a single or double socket, or a fused unit) is allowed per spur, you cannot add more spurs than there are outlets on the original circuit and they must be evenly distributed. Yes, that's a slightly odd rule, but it sort of makes sense - stops people trying to cram six 2.5mm² cables into terminals designed for three. The even distribution is even more important where the circuit is a ring rather than a radial.
Because of the way UK plugs are individually fused, even if you wire the spur in the wrong sort of cable you are unlikely to cause any major hazard, though if you choose to plug two 3kW kettles into a double socket on the end of a spur wired in 1mm² you do so at your own risk. Your main danger is wiring the thing wrong - I once saw someone wire a plug with the E wire in the L pin - but those plug-in socket testers are cheap and while they won't flag up all faults, they can at least tell you if you've got the wires the wrong way around.
Adding a new circuit however is a whole other kettle of fish because it leaves open the possibility that someone may come along in the future and extend your circuit. Have you checked that the board is suitable for the potential increased load? Have you considered other upgrades to the system that might be required? Have you used the correct cable? Have you used the correct sleeving? Have you used the correct protection (MCB / RCBO)? Have you installed the cable correctly (i.e. clipping*, protection from damage, routing, minimum bends etc? Have you checked that all the terminations are correct at all the outlets? Have you carried out an insulation test to prove that the cable has not been damaged during insulation? Do you know the prospective fault current? Have you tested the RCD (RCBO) to prove that it meets both the slow- and fast-trip response times? (yes, I have had a brand new RCBO fail the test)
Now, a qualified electrician would - or should - check all those things even if just installing a spur, but the regulations are pragmatic regarding DIY.
M.
*plastic clips are generally ok but where a cable crosses a fire escape route - even if above a ceiling - fireproof clips must be used. Yeah, check out the price difference.
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Friday 20th May 2022 15:11 GMT An_Old_Dog
Re: Sparkies...
In the 1990s I was helping set up a Unix system which was to connect to (among others) a group of three intelligent terminals in an office 900+ miles away from the host. The connection was via a set of statistical multiplexors over a dedicated line leased from the national telco. As it was a dedicated, point-to-point line, there were no telephone numbers associated with it.
The sparkies at the remote office called me at the main office and said things were ready to go. I hooked my stuff up and enabled logins on those three RS-232C ports, called the secretaries at the remote office and had them (try to) log in, but they got nothing on-screen. I had them tap the Enter key a couple of times, and got nothing on the host end. Yup, their terminals' status lines showed connectivity with their stat mux, and my serial line monitor showed connectivity between the host and the stat mux in the main office. Gettys were running on the correct three ports, and my serial port monitors showed correct RS-232C signal statuses.
On each end, between the stat mux and the actual line connection was a CSU/DSU box, which was not in my area of knowledge. I looked at ours, and noted a green LED lit, and a red LED lit. I called the guy who knew about the CSU/DSU, and he said something was wrong with the line.
I had the remote secretaries hand their phone to the head sparky on-site, told him what I knew, and he replied, "The line's good, I checked it and it's got tone."
Me: "It's a dedicated line. It's not supposed to have tone."
Head Sparky: "Oh."
Three days later they got it fixed.
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Friday 20th May 2022 09:50 GMT Chris King
PCSA, Vampire Taps and All-In-1...
Damn you, I'm still drinking to forget them...
Shouted across a room - "Log in to All-In-1, I just sent you a message!"
Thicknet cables with their 15-way D connectors used to confuse users, who would plug them into the joystick port on their sound cards and wonder why they couldn't connect. (Younger readers - this is much like plugging your RJ45 network drop cable into an ISDN card),
Thicknet was positively skinny compared to the inter-floor hydra cable I encountered on one site. BICC ISOLAN hubs serving two floors, delivering RJ45 Cat 3. Yes, you read that right, Category 3. I can't remember how many U's they took up in the cabs, but "many" springs to mind.
For extra giggles, the ISOLAN network cards in the PC's would release their magic smoke if anyone ever attempted to install Windows 95. Log in, and your machine would be impersonating Robert the Robot from Fireball XL5 within moments.
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Monday 23rd May 2022 15:29 GMT Loyal Commenter
Re: PCSA, Vampire Taps and All-In-1...
This, and I've seen people who were around in the age of PS/2 keyboards and mice, and who definitely know what they are doing, plug their USB ones into RJ-45 sockets. Because it does fit, and when you're reaching around the back of a laptop that's sat on a dock or a riser, to plug something into it, it's pretty easy to do.
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Friday 20th May 2022 12:58 GMT OldSod
Re: PCSA, Vampire Taps and All-In-1...
Twisted pair hubs were a big step up from 8-port 10BASE2 (thin wire) DEMPRs (Digital Ethernet Multiport Repeaters) used for either individual office homerun cabling or (for the more cost-conscious) or whole hallways of daisy-chained PCs. THOSE took up a lot of rack space.
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Friday 20th May 2022 10:01 GMT Neil Barnes
Of earths
I found myself in Dushanbe, in Tajikistan, doing a radio studio installation (including some early 486 machines running audio editors, but their story has already been told). Normal practice at the time was to find a nice big water pipe as a ground. It was such a shame that for reasons we never discovered, there could be two hundred volts between the heating pipes, the water pipes, and the mains ground, depending where you looked...
We gave up trying and drove a big spike instead.
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Friday 20th May 2022 12:33 GMT dvd
Re: Of earths
I worked somewhere where there was (IIRC) about 80 volts between the central heating radiators and the cases of the PCs. Not enough to kill you but pretty noticeable.
The building manager refused to believe me but for some reason wouldn't touch the radiators and PCs at the same time either.
I had to get a Fluke to prove it to him.
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Friday 20th May 2022 16:35 GMT adam 40
Re: Of earths
When I was a whippersnapper at uni, I went to stay with a friend, his dad was a sparkie at Goodyear in Wolverhampton.
As I walked through the kitchen, I brushed close to the microwave. The casing was stainless and vibrating 50Hz. So I pointed it out.
Out came the screwdrivers, and dad whipped off the plug, a proper job MK one. But the hole at the top, moisture had got in, and the earth wire was all corroded.
Stripped back, fresh copper exposed, plug back on, normal service resumed. He asked me how I knew, and I just told him, I used to play with old TV's when I was 12, (live chassis) and I knew that mains leakage feeling a mile off!
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Saturday 21st May 2022 19:21 GMT druck
Re: Of earths
I had a similar experience back in the 2000's with a HP iPaq we were developing on. When put on charge it's smooth metal case changed to feeling slightly rough, this was due the 50Hz mains frequency vibration which meant it wasn't properly earthed. The boss couldn't detect it and didn't believe me, so challenged me to a test to see if I could feel it while he surreptitiously switched the charger on or off. I won the challenge, but he wouldn't let me take it apart to see what the problem was! I've since found lots of other electronics have the same issue.
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Sunday 22nd May 2022 01:54 GMT J.G.Harston
Re: Of earths
"I used to play with old TVs when I was 12, (live chassis) and I knew that mains leakage feeling a mile off!"
Thank god, it wasn't just me! I used to think I had some wierd superpower, nobody would ever believe me that I could "feel" mains power, and I just taught myself never to mention it to anybody. Thank goodness it's just plain old physics.
Now, dare I tell anybody I can "feel" increases in air pressure? I can tell you there'll be a thunder storm an hour before it happens.
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Saturday 21st May 2022 04:45 GMT jake
Re: Of earths
It ain't the volts that kills you, it's the amps ...
That said, in my first live-aboard boat there was enough power between the water and the shore-power's ground to keep my batteries trickle charged. Needless to say, I took good care of my zincs and made certain everything important was properly bonded.
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Saturday 21st May 2022 20:40 GMT Stoneshop
Re: Of earths
I worked somewhere where there was (IIRC) about 80 volts between the central heating radiators and the cases of the PCs. Not enough to kill you but pretty noticeable.
Happens when your average PC chassis isn't actually connected to ground. The mains power noise filter usually has a pair of capacitors sitting between the mains legs and chassis, the value of which would be like having a 50..100k resistor there, at 50/60Hz. So if the chassis wasn't grounded to the mains (or a water or heating pipe that was), it would be floating at half the mains voltage with a equivalent series resistance of several tens of kOhms. Touch the chassis and that water pipe or an unpainted part of the heating circuit (like the radiator valve), and you feel those volts, though the resistance the circuit imposes means you won't get a painful jolt.
A fellow student had that same complaint. Showed him that between the radiator in his room (which he had brushed while touching his PC's chassis in some way) and the ground pin in the wall socket there were just a few Ohms, but between both ends of the ground wire in the PC's power cable there was so little conductivity that my Simpson 260 considered that to be infinity.
I had to get a Fluke to prove it to him.
Beckmann used to advertise "It's not a fluke, ours work by design."
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Friday 20th May 2022 15:34 GMT elkster88
Re: Of earths
I've recently become aware that building power entry earth connections in the middle eastern desert might as well be connected to nothing but free air, until / if it rains heavily, at which time the earth connection becomes functional. Otherwise it's just a big metal spike surrounded by dry grains of sand, which functions as a good insulator. This plays havoc with sensitive noise measurements.
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Saturday 21st May 2022 03:51 GMT PRR
Re: Of earths
> ...earth connections in the middle eastern desert might as well be connected to nothing but free air, until / if it rains heavily....
Nearly the same here. Coastal Maine USA looks damp. But the "ground" can be less than a foot of coarse sand over infinite granite. It is unremarkable here to find ground rods laid near-horizontal rather than stright down. And to have multiple dirt-rods yet still not have enough conductivity to light a 100W lamp (that's apparently/allegedly a rough-test for installations in India). With five dirt-rods from the house to below the septic field I still have 60 Ohms in Spring, and more in summer drought or winter freeze.
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Saturday 21st May 2022 05:02 GMT jake
Re: Of earths
Same thing in the high desert in Nevada. When I put in the tractor shed (140" X 100"), the concrete contractor strongly suggested I put an Ufer Ground in the new foundation, and then carefully tie everything into it.
Let's just say that I'm glad I took his advice. We have absolutely zero electrical issues, but my neighbors are constantly bitching about it.
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Friday 20th May 2022 10:22 GMT ColinPa
almost whoops
We were working in an old building, and someone wanted to hang a few pictures on the wall,so had a hammer and some 4 inch nails.
One of the old hands told us to be careful. He said that the high voltage cable wandered around. It should go up and down, and be in a protective tube - but not in this building. Sure enough, we pulled the panel back from the wall to have a peek, and there was a cable just wandering around (in coils), not secured etc. It was not done by electricians, but by some people who wanted a "quick fix" until it was done properly.
The old hand said don't look under the raised floor - so we did. If people wanted to add new connections - they just added new ones - and left the old ones behind. It was 9 inches deep in cables.
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Friday 20th May 2022 10:37 GMT lglethal
Re: almost whoops
And as a hard working and dedicated BOFH, you took the time (most likely in the middle of the night, with the security cameras having mysteriously gone down for the evening) to tidy up the arrangement and clear out all that unneccesary copper cabling. You were also no doubt, so dedicated to the task that you took the cable for recycling to the nearest Copper recycler, and didnt even charge the company money for the transportation of the "scrap" cable.
The whole, being able to afford a new car afterwards thing, that's just purely coincidence...
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Friday 20th May 2022 16:27 GMT Andy A
Re: almost whoops
I was once officially tasked with tidying up such a floor void. It took a whole week between normal tasks.
Naturally I had to also officially remove the offending cabling from site. I had an appropriate "chitty" as I left early one Friday.
The Recyclers handed me a cheque (shows you how long ago this was) which filled the car up for a month, and a few of the icons too. =====>
The following week, more cabling was installed, but at least we could see where to fit it.
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Friday 20th May 2022 16:58 GMT Mark 85
Re: almost whoops
And as a hard working and dedicated BOFH, you took the time (most likely in the middle of the night, with the security cameras having mysteriously gone down for the evening) to tidy up the arrangement and clear out all that unneccesary copper cabling. You were also no doubt, so dedicated to the task that you took the cable for recycling to the nearest Copper recycler, and didnt even charge the company money for the transportation of the "scrap" cable.
Way back being a young lad straight out of the military and going to college, I worked as building maintenance for a year in a downtown office building. A really old build and copper pipes were "wearing out" with pinholes and bad joints. The owners decided to replace all the piping. The old pipes needing disposal was tasked to me. I talked to the manager and we ended up selling the copper to a recycler. I paid for a years tuition from that and the manager got a new car.
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Friday 20th May 2022 11:14 GMT Plest
Re: almost whoops
".. wanted to hang a few pictures on the wall,so had a hammer and some 4 inch nails..."
Holy crap, how big were these pictures?! Having said that my brother-in-law when he got his first satellite dish for Sky back in 1991, I put it up using six 4" sleeve anchor bolts. I went past his old house about 3 months ago and the bolt tips are still there, the dish has long since gone and the area painted over but you can still see those 6 holes I made are 30 years ago and the ground off bolt tips! Ha ha!!
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Saturday 21st May 2022 16:17 GMT eldel
Re: almost whoops
24 I think since they perished. Loved working there. Not unlike the 60s if you remember the parties ( Xmas, launch etc) you weren't there.
When they went into liquidation everyone had to go get their personal stuff from the office and the receivers had a couple of heavies on the door making sure that nothing else was taken out. What they didn't seem to realize was that the 'machine room' was on the ground floor and had opening windows. Apparently by the time anyone twigged to this there wasn't a lot left. It would appear that the windows were large enough to get HP 'N' (?) Class servers out through. Allegedly.
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Friday 20th May 2022 11:37 GMT DaemonProcess
Re: almost whoops
Yes I've seen that too - 9-12 inches of solid cable under floor. They could barely get the tiles down on the top layer. At the bottom of it all was the 40 year old analogue phone system and alarm. At least that building was being powered down and decommissioned.
As opposed to the 2 electricians I once saw arguing over 3 black cables connected to my shiny new HP Superdome (64 kilowatts) arguing over which black cable was the blue phase....
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Friday 20th May 2022 12:23 GMT Giles C
Re: almost whoops
Yep always the same when old phone systems are installed. Mind you this does remind me of a tale - which is true.
We were putting new cables under the floor of the comms room. There is myself and another guy working through the same raised tile moving the cables around.
One of the cables is a brand new (installed a couple of days prior) 32A commando socket. This was in the way so I picked it up and moved it. At this point the cable which hadn’t been secured in the socket properly moved and dead shorted the connection. Which was too much for the breakers and took out the power for the site (including all equipment and the lights at once).
After resetting the breakers and getting the building back up we finished up and went home, this was on a Saturday evening and I took Monday as a day off.
The internal rumour mill went into overdrive after the weekend to the point at which the story going round was I had a major electric shock and was in hospital / dead take your pick.
My colleague was insisting I was fine on the ground I had got a bad shock so would he as we were working close by, but nothing stops a good rumour….
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Friday 20th May 2022 13:37 GMT Tim99
Re: almost whoops
A very long time ago we were given 2 bathroom cabinets as wedding presents, we only had room for one, so we gave a relative the other. A few days later I went to his house. The new cabinet was mounted on the bathroom wall 15° off vertical. Opening the cabinet door, I could see the heads of what looked like 2 x 4" nails that he had used to secure it to the wall joist, instead of the 4 x 2" screws that were probably required - The cabinet was supplied with 4 countersunk holes.
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Friday 20th May 2022 14:27 GMT Vulch
Re: almost whoops
Under the raised floors at the ITV station I worked at were like that. Studios built and wired for 405 lines monochrome, rewired for 625 monochrome, rewired again for 625 colour, new studio built with all the extra wiring for that, sound rewired for stereo, franchise lost and studios demolished before rewiring for full digital was required.. Can't pull the old cables out until the new has been shown to work, can't pull them out then as there's too much weight on top of them. Nothing quite with enough layers to stop the floor tiles going back down, but close...
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Friday 20th May 2022 21:53 GMT Doctor Syntax
Re: almost whoops
Don't forget that if once you've installed two cables they'll start breeding. It's just like the box in the cupboard where you put those old RS232 cables. Next time you look there'll be a handful of mains cables, some CAT5 patch cords, at least one video cable and one with connectors you don't even recognise.
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Saturday 21st May 2022 03:34 GMT doublelayer
Re: almost whoops
And also that cables are shape shifters. I have a box of mostly USB cables, but even though there appear to be at least twenty in there, there is never the old variant of USB that I need when I search it. This is even when I've searched it for different things on separate occasions: when I need it, it's not there. I do have a USB-A to USB-A cable that just makes the wire longer, though. I'm sure I'll need that eventually.
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Sunday 22nd May 2022 00:01 GMT Stoneshop
Re: almost whoops
I do have a USB-A to USB-A cable that just makes the wire longer, though. I'm sure I'll need that eventually.
Plug to socket. That's quite normal.
Now a cable with USB-A plugs both ends? And not one of those "connect two hosts so you'll have a sort of network with disk sharing" cables with a lump in the middle. A LapLink version for the early USB era.
Oe one that goes from USB-A to Firewire, without any converting gubbins, just galvanic connections.
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Sunday 22nd May 2022 17:35 GMT Jason Bloomberg
Re: almost whoops
I remember going into Maplin and seeing A-A cables. No idea who they sold them to.
When cheap digital cameras first acquired USB, many had A sockets, so you needed an A plug to A plug cable. I recall some early MP3 players being the same.
I have quite a few. They are very useful for back-powering headless Raspberry Pi computers, avoiding the need to have a power connection to the side. You only need to solder a flying wire to bypass the USB current limiter to make it work.
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Monday 23rd May 2022 15:35 GMT Loyal Commenter
Re: almost whoops
You only need to solder a flying wire to bypass the USB current limiter
And they called me mad? Mwahahahaha!
And so on and so forth.
I mean, bypassing a current limiter could never possibly go wrong, could it?
I know R-Pis are pretty solidly made with good engineering tolerances, but that's asking for trouble...
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Saturday 21st May 2022 20:56 GMT Stoneshop
Re: almost whoops
It was 9 inches deep in cables.
At DEC Nijmegen, where I was stationed as site engineer, the raised floor in the computer room was nearly 3 feet high due to a design being misread. So one could run a new cable just by popping the tiles at both ends, dive into one and crawl across pulling the cable.
This of course was not really conducive to proper cable management, and in several places where cables tended to concentrate there were veritable cable strata, probably going back to the mid-Pleistocene.
Also, one day some electrical work was being done, with suddenly an underfloor bang and the disks in several cabinets spinning down. Then a tile popped up and a sparkie emerged, looking remarkably pale for an Indo and hesitantly saying "oops".
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Friday 20th May 2022 11:43 GMT MiguelC
Re: Sparkies
There are all kinds, when I redid my kitchen, one sparky tried to burn my house down, the other spotted the problem and saved my arse.
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Friday 20th May 2022 10:57 GMT John Riddoch
Ah, earth problems...
Had a much less hair raising experience with that - bought a 2nd hand guitar and got a chunk off because it was buzzing loudly when plugged into the amp. Took it to bits and discovered they'd wired the jack socket wrongly when it was replaced... 5 minute solder job to switch round the wires and no more buzzing :)
Now onto fixing the other issues like the frets needing polished, rusty screws replaced and updating the pots (one doesn't work, so might as well switch out the cheap ones for better models). I'm beginning to think I didn't so much buy the guitar as rescue it from neglect...
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Friday 20th May 2022 11:05 GMT John Doe 12
What On "Earth"?
Sadly this story also seems to show up the teller "Andrew" as not being very electrically savvy either....
"...and if they turned on the power not only would the circuit not be earthed, but hundreds of thousands of pounds of computer equipment would go up in smoke."
The second half of this comment is utter bullshit in all but the most extreme circumstances. Unless something goes terribly wrong then the earth is not powered up in any form. Of course this situation would leave a potential disaster to happen further down the road but as it stands that statement is 50% hyperbole!!
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Friday 20th May 2022 11:49 GMT AndyMTB
Re: What On "Earth"?
Talking about twisted-pairs and wiring - I asked on our local freecycle site if anyone was getting rid of an old lawnmower/raker. I just wanted a pair of handles. Was invited to pick up a defunct mower which had the appropriate handles, it looked quite new (and was a good quality machine). When I got it home I noticed the cable had obviously been run over, and was patched up with coloured insulating tape. Surely that couldn't be the reason it wasn't working? Unravelled the sticky tape to inspect the join and found....let hand side of cable, blue and brown wound together, the same on the rhs, then both twisted ends wrapped together and securely taped. Had to wonder how many fuses/circuit breaker re-sets he'd gone through before abandoning the fix!
Anyone want a fairly new electric lawnmower (no handles)?
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Sunday 22nd May 2022 11:22 GMT Giles C
Re: What On "Earth"?
English and American electrician working on the same machine. (In England)
American: is the machine hot?
English: (putting hand on casing) nope
American: (using screwdriver)I just got a shock you said it wasn’t hot.
At that point it dawned on them that to the English a LIVE machine is powered up whereas in America a HOT machine is powered up.
Separated by a common language
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Tuesday 24th May 2022 10:25 GMT Anonymous Coward
Re: What On "Earth"?
I had to manage an incident where the sparkies somehow connected a three phase supply to a single phase incomer and fried everything plugged into the wall outlets. At a newspaper publisher with a Monday deadline for printing and all the copy on the PCs. We were semi-fortunate that some had UPSs that took one for the team and while rendered into scrap, did enable the downstream devices to survive. We cannibalized every PC we had around our IT shop and juggled power supplies until everything had been recovered and we had a core set of working systems from which to print the copy for the issue. That was a busy weekend.
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Friday 20th May 2022 14:14 GMT Phil O'Sophical
Re: What On "Earth"?
then the earth is not powered up in any form
If they had mistaken it for an earth, and connected it to some equipment that had RC filters on the mains input, it's not impossible that the cable could be left floating at half-mains voltage through the filter chokes. An earth is only going to be at ground potential if it's actually earthed.
I've seen this, a friend in a very rural home commented to me that the washing machine in an outbuilding gave her a shock when she touched it. A quick meter test showed that the case was indeed half-live, and when the local electricity board came out they found that the main earth spike for the house wasn't connected (corroded through), so nothing was actually earthed...
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Friday 20th May 2022 14:21 GMT John Doe 12
Re: What On "Earth"?
I would point out that you selectively quoted me there which at the very least is unfair. Originally I wrote "Unless something goes terribly wrong then the earth is not powered up in any form".
Of course anything is possible but my gripe was with the storyteller basically saying it was a done deal that things would be blown up the moment the electricians powered up their installation which is in most circumstances totally untrue.
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Friday 20th May 2022 15:32 GMT Potty Professor
Re: What On "Earth"?
Soon after we were married, we bought a cottage in a village near where we both worked. My wife complained that she was getting a tingle from the cold tap in the bathroom sink, so I checked it for potential, and found that it was securely earthed. She said to put some water in the sink, and then touch the tap, sure enough, a small tingly feeling was experienced. I checked the plughole surround, and found that it was at about 50V from the earthed tap. I traced the source to the overhead cable running across the yard to the shed, the flat twin and earth had deteriorated in the sun where it was bent at a 90° angle to go from the vertical run up the outside of the brickwork to the underside of the horizontal catenary across the yard. When it rained, the current flowed out from the live wire into the damp brick, across to the lead waste pipe, through the wall, and up to the brass plughole. I cut out the lead pipe and replaced it with a plastic one, which solved the immediate problem, but later on I had to run a new SWA cable across to the shed to stop the leakage into the brickwork. I avoided the sharp bend by introducing a "Pigtail" curve at the minimum radius of the cable.
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Saturday 21st May 2022 12:26 GMT Martin an gof
Re: What On "Earth"?
flat twin and earth had deteriorated in the sun
This sort of cable should never be used outdoors - it doesn't like the UV from the sun or the wide swings in temperatures. While SWA was probably not strictly necessary for an overhead cable, the stuff I used to use which was called "HiTuf" and was constructed in exactly the same way as SWA but without the steel wire armour no longer seems to be available. Then again, even "outdoor rated" cable deteriorates more quickly than you might expect* and needs regular inspection. Same goes for certain types of waste pipes commonly used for (for example) sink outlets. In fact the sun is pretty harsh on quite a lot of plastics.
M.
*that is, while Twin & Earth PVC cable seems to be good for 60+ years indoors (some people claim that as it shows no sign of deterioration after 50 years (so long as you haven't used the wrong type of cable clip), it's probably effectively good forever), I've seen badly damaged T&E which has been exposed to sunlight for less than 10 years. Outdoor rated cable is definitely better, but should be inspected as a minimum every 10 years** and my gut feeling is that 30 to 40 years is likely to be about as much as it can take. Older rubber-insulated cable indoors only lasts 20 to 30 years before becoming too brittle to be safe, so if your house was last wired in the 1950s or early 1960s it really needs doing again.
**regulations guidance is that domestic installations should be re-inspected every ten years anyway
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Sunday 22nd May 2022 09:37 GMT Stoneshop
Re: What On "Earth"?
the current flowed out from the live wire into the damp brick,
An uncle was moving house, and of course some of the family (including me, age 16) were helping getting stuff in shape as in several rooms the walls had been stripped and re-plastered.
I was hanging a ceiling lamp in one of the rooms when I happened to brush my fingers over the plaster near a wall socket, and sensed a rather surprising 50Hz buzz. Which was strongest right up from the socket to the ceiling, and fell off the farther you moved from that line. You could even get one of those neon-bulb voltage probe screwdrivers to light up if you held the tip to the wall while touching the radiator valve body. So there was serious current leakage from the socket's wiring.
Showing this to my uncle he declared it Not Good, and gave me permission to expose the conduit and find the cause of the leakage.
Well, the plasterers had clearly wielded their Hilti with great gusto to get the old plaster off but had not shown any care regarding the (iron) conduit, which apart from being almost entirely hammered flat, showed several serious rips with, of course, jagged edges with the wiring inside showing damaged insulation. Unfortunately, in some way, not a full short since that would have shown the problem as soon as they had hit the conduit.
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Friday 20th May 2022 20:21 GMT H in The Hague
Re: What On "Earth"?
"I've seen this, a friend in a very rural home commented to me that the washing machine in an outbuilding gave her a shock ..."
Problems like that with outbuildings are quite common. Sometimes you'll get a potential gradient across the yard between the outbuilding and the main building due to earthing problems, leakage, etc. As cows have their legs widely spaced and don't usually sport insulating footwear they are sensitive to that as they experience quite a large potential difference between their front and rearquarters - so if your livestock refuse to cross the yard that might be due to an electrical issue.
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Friday 20th May 2022 11:10 GMT diver_dave
From the domestic side
50v L-E is something I see regularly. Normally a fluorescent fitting died
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Having worked both sides I'm always very very careful with Band 1 and Band 2 cable separation.
On the earthing side. Several times I've seen the earth used instead of fitting 3 core cable for 2 way lighting. Plus I had the delights the other week of tracking a fault following Easter DIY work. Somehow client had managed to feed all the upstairs lighting from one of the 2 way strappers. Obviously, in the loft, on a hot day and under 3 layers of insulation.
Joy.
Great weekend all.
Dave
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Friday 20th May 2022 11:21 GMT Anonymous Coward
Re: From the domestic side
My dad was always teaching me stuff about house wiring and he said the funniest ones are
- watch someone get confused working out why the live/neutral appear back to front in certain places
- watch someone try to work out the wiring in most living rooms where you have two pair of two way switches
- finally watch when they wire it all wrong and either watch the breakers constantly jump or find they get lights on but then can't get them off again!
He said he's earned more than his fair share of free beers after getting calls from mates who've pulled out the living room wiring and their hair, trying get two-ways working again.
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Friday 20th May 2022 13:57 GMT Roger Lipscombe
Re: From the domestic side
"watch someone try to work out the wiring in most living rooms where you have two pair of two way switches"
For whatever reason, our kitchen has 3 switches for each set of lights -- one by the hall doorway, one by the dining room doorway, and one by the back doors. When we had some electrical work done a few years ago, I think it took the sparky several hours just to figure out what the hell was connected to what.
To be fair, though, we've been in the house for nearly 15 years, and I've still not figured out which switch goes with which lights.
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Sunday 22nd May 2022 10:09 GMT Stoneshop
Re: From the domestic side
our kitchen has 3 switches for each set of lights -- one by the hall doorway, one by the dining room doorway, and one by the back doors
I was faced with having to wire two workshops, each with two sets of central lights, like that.
Conventional switches? These would all have to be splash-proof, and while appropriate 3-ways were available I couldn't find the 4-way ones that would be required as well. Also, lots of wiring.
Buttons controlling pulse relays? Better, but somewhat crude still. And as I was thinking of adding a couple of presence sensors to switch the lot off when neither of us was around that would have added more relays, an arduino or a PLC.
In the end I went for a home automation solution, with splash-proof buttons (from the same series as the wall sockets) simply sending a 'flip' command to the appropriate lights actuator. The additional features this allows such as a 'central off' are a nice cherry on the cake.
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Friday 20th May 2022 14:01 GMT diver_dave
Re: From the domestic side
Oh yes....
Take the ceiling rose out and both 2 way switches. Chaos ensues given you can almost guarantee that the N cores have been used for switching.
It's a joy to take 2 continuity readings and put it back together working, then listen to SWIMBO lecture husband.
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Friday 20th May 2022 15:56 GMT diver_dave
Re: From the domestic side
I know it sounds silly but maybe more electricians would sleeve if you didn't have to buy 100m looms or pay through the nose for short lengths.
I go through 200-300m of earth sleeving a year and probably 5m of brown and blue.
Anyway.
Friday, clear weekend, pint o'clock.
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Saturday 21st May 2022 12:33 GMT Martin an gof
Re: From the domestic side
Do you need any? I've got probably 90m of brown and blue left after building this house and quite possibly 50m+ of green&yellow. And that's after keeping a few m for future use.
I wired to the switches rather than the ceiling roses, so a: only one cable at the ceiling fitting (meaning those stupid fancy Italian-designed lights they seem to sell at B&Q are much easier to wire) and b: no "switch drop" which is where you usually have to sleeve the blue wire with brown as it becomes "switched live".
Two-way and three-way switching accomplished with 3&E cable to the very simple On Site Guide plan. 3&E is brown-black-grey which are all "live" colours these days so don't actually need sleeving, though sometimes it's a good idea to anyway.
On the downside, more wires in the backs of switches, but as this was a new build I just put a 25mm or 35mm box behind each switch instead of the 16mm commonly used in the past.
M.
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Sunday 22nd May 2022 16:08 GMT Stoneshop
Re: From the domestic side
maybe more electricians would sleeve if you didn't have to buy 100m looms or pay through the nose for short lengths.
As I gather it's meant to mark individual wires in a cable having a different function (i.o.w. make it the right colour), wouldn't you just use a bit of shrink tubing, or is that Frowned Upon by the electrical code? I do so all the time.Maybe it wouldn't be totally correct, but at least it's more correct than not doing it at all.
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Friday 20th May 2022 11:34 GMT BenDwire
1980's CAD
Way back in the 1980's I ran PCB design software (Daisy) that ran on a couple of proper IBM 386 systems, linked together with 'Thicknet' . Unfortunately these were side by side, so the cable was simply coiled up under the desk, complete with vampire taps and separate AUI (?) boxes with a variety of connections. IIRC there were two thick blue coils as well at the yellow. Time and alcohol has dulled the memory.
It's amazing how good those systems were back in the day, at least compared to the other solutions we had available. I'm fairly sure that they had full length ISA cards with 4MB (not a typo) worth of discrete chips plugged into IC sockets, and full length Matrox graphics cards. Of course the whole lot ran on Unix, so it was completely stable.
Good days. Now get 'orf me lawn!
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Friday 20th May 2022 15:45 GMT Potty Professor
Re: 1980's CAD
I used to run a desktop publishing setup (Xerox) for an electrical company. Due to a reorganisation, we had to move our kit to a temporary office. We ripped out the old thick ethernet cable from the ceiling void and lugged the whole length down to the new building. Rather than struggle to install it all up in the Gods again, we coiled it up on a cable reel, attached the five vampires at the correct places, and put the cable reel in a cupboard. The dropper cables were then routed to the computers and the printer, a much easier job than lugging the thicknet around. Of course, we never moved out of that "temporary" office, so the system was still installed when we were all made redundant.
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Friday 20th May 2022 12:13 GMT Anonymous Coward
Any cabling and engineers
We had issues with the door access system (Of course it was an IT issue).
Door access engineers came on site and found CCTV enginners re-using their network (It was segregated and they spent a huge amount of time getting it in). The engineer who knew exactly how much time this took them was rightly pissed off.
Another job added to IT's stuff to deal with, seperating the fuming Door Access Engineer from the CCTV engineer.
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Friday 20th May 2022 12:37 GMT My-Handle
Re: Any cabling and engineers
Separating?
I thought it was IT's job to provide the two engineers with a private, preferably sound-proofed room within which to 'discuss' their differences. Potentially with the aid of a half-brick which was strangely left in one corner. Odds are you'll be free of one more inept engineer.
Oh wait, this is the On Call column. Sorry, thought I was reading BOFH again. Carry on.
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Friday 20th May 2022 19:35 GMT navidier
Re: Any cabling and engineers
> Separating?
Yes, it's a very common spelling mistake. My old teacher, back in the late '50s, when my brother and I used to get a cut of the cane for each word we got wrong in the weekly spelling test[1][2], came up with a good mnemonic :"there is A RAT in the separator". Since we were working a dairy farm at the time, and most of our income came from the cream sent to the local Norco buttery, a (milk/cream) separator (basically a centrifuge) was an important part of our dairy and had to be kept scrupulously clean.
[1] We were both learning at a level above our physical ages, so more was expected of us
[2] A one-teacher primary school literally in "the bush"
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Friday 20th May 2022 13:18 GMT NXM
ITN
A mate of mine told me that in the lovely new ITN building in London when it was just finished had huge amounts of cables in the risers between floors.
Sadly, the installers hadn't put the required loops in at each floor, so the weight of the cable below would eventually pull the cable apart.
The installers had to strip the whole lot out and do it again - properly.
Also, I've had several occasions where earth wasn't at earth potential. Once in an office with several PC's on a long line of 4-gang adaptors where one in the middle had a missing earth connection, resulting on the cases being at about 50V ac! Ow.
And sometimes switched-mode supplies used to hold their (isolated) outputs a few volts above earth, and if you earthed the negative output the supply shut down. Never got to the bottom of that, probably something to do with eddy currents.
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Friday 20th May 2022 15:08 GMT Boris the Cockroach
ohhh god
sparkies <Starts sobbing as the PTSD kicks in again>
Back in the good old days of my previous employment, we had a specific shutdown order for the machines, with isolators being turned etc etc... this is because there were a few transformers on the power circuits and they had a habit of firing volt spikes back into the power systems when they were shut off, not enough to damage most of the machinery, but if the machine was powered by a PC type control.... bingo instant blue screen (along with all the office PCs of course)
However the sparkys hired for the job of wiring in new plant ran the power cable to the main distribution board.... took the perspex cover off , then realised they needed to shutoff the power in order to install the latest wiring... so they did.... when the dust settled, the blue screens cleared and the plant restored to running order a few hours later, they were asked 'Did you see the sign saying "DO NOT SWITCH OFF WITHOUT AUTHORIZATION FROM THE MANGLEMENT" ?
What sign?
The one on the perspex cover you removed and put on the floor next to the cut off switch..
We changed that to a hinged cover with a padlock.....
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Friday 20th May 2022 16:29 GMT meadowlark
COMPLETE REWIRE.
Although somewhat off subject, many years ago I went even further down in my late widowed mother-in- law's overall opinion of me. Her light in the hall was flickering so I had a look at it for her. My knowledge of all things mains power in those days was virtually nil. I could replace a fuse in a plug, and before circuit breakers came in, repair a fuse in the house fuse box with the appropriate thickness of fuse wire, but that was it.
So I turned off the electric, took out the light bulb, and checked that the wiring to the bulb holder (pendant ?) was okay, which it was. I then turned my attention to the ceiling rose which I undid to check the wiring coming out of the ceiling. The wiring for the whole house was very old, probably being the original from 60 years before. I could see that there was a loose wire and instead of just tightening the screw, I unscrewed it and pulled the wire out completely (don't ask).
Big mistake. The insulation was so brittle it all came off like a piece of bone china breaking, and I was left holding bare wire. No problem (I thought), I'll just pull a piece of slack through and nip off the bare wire. Well as I did, the brittle insulation just kept falling off like dead leaves from a tree in autumn. I gently kept pulling but eventually there was no slack left, and just a 12" piece of bare wire disappearing into the ceiling.
Even I knew I couldn't put lots of insulation tape on and reconnect it. Well I could but it wouldn't exactly be safe. I therefore had to break the bad news to my mother-in-law that I'd have to contact a qualified electrician for her. I was there when he eventually arrived and I was half expecting what he was going to say. He checked the state of the wiring generally and advised that a complete house rewire was required. The look my mother-in-law gave me can only be imagined.
Because of the age of the house, channels had to be made in the plaster of the walls to accommodate the wiring and capping. So course, she had to get a decorator in to repaper the rooms. From then on, I never once offered to do any more jobs for her as I knew what the answer would be !
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Saturday 21st May 2022 01:22 GMT Antron Argaiv
Re: Yellow? Perhaps in Britain.
Orange was plenum safe (low smoke) required when being run above suspended ceilings also being used as return ducting for HVAC.
Yellow was the non plenum safe version.
Fun fact: Ethernet "thicknet" coax is almost exactly RG-214 coax cable with a solid center conductor instead of stranded. I have a roll in the basement I have used as antenna feedline. Works fine.
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Friday 20th May 2022 17:53 GMT J. Cook
least your sparkies didn't accidently connect the second phase to a circuit's neutral/return line and blow up the power supplies on two brand new computers and make the server's UPS immediately shut down to have a sulk...
(power supplies that are auto-ranging typlically expect 120 or 240 vac on a single hot, a neutral/return line, and an earth line- replacing the neutral with a second phase made the stored pixies in the capacitors of those supplies angry enough to spontaneously combust...)
icon, because that's what the PSUs did...
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Saturday 21st May 2022 17:49 GMT Eclectic Man
Re: reverse psychology
The psychology of "do not" do something is tricky in that it informs the recipient of some act they should not perform, and that they are probably capable of performing it. Instead of "Do not touch", how about "Leave alone"?
Arthur Dent "what happens if I press this button?"
Ford Prefect "DON'T!"
Arthur Dent "Oh"
Ford Prefect "What happened?"
Arthur Dent "A light lit up saying 'please do not press this button again.' "*
*(HHGTTG, first series. I'm a personality prototype, you can tell can't you?)
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Friday 20th May 2022 21:52 GMT Anonymous Coward
Still see the odd bit of thicknet cable in our hospitals, with the markings for the vampire taps.
One of the server rooms is still called PDP Room.
Still find the odd screw terminal DP from the phone system which was in before the old ISDX.
One of my old schools found out the the science end of the main building had a earthing issue after a flood. (Sparking walls ). Kids had complained of shocks but ignored. School was around 30 years old at that point. Big TT spike was put in the ground.
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Saturday 21st May 2022 10:11 GMT andrewmm
building earthed through ThickNet
No ones ever going to read this far down
but anyway
Worked in Sicily back in the 80's,
Interesting job for the local "family" , but thats another story
A large part / all there money came from European pots
one of which had paid for a lovely new building I worked in
Even had back up power , which was needed every afternoon
The two building , connected by a long path, with a flat roof above,
Laid on that roof, was the Thicknet Cable, to connect the two IT systems,
Cable nicely earth bonded at both ends to "ground"
But "ground" was many meters of sand,
All lovely, till an engineer had to move the cable and separated a joint,
resultant bang as guy was thrown form roof,
yep the connection between the two buildings was the screen of the cable !
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Sunday 22nd May 2022 11:27 GMT Man inna barrel
Beware plumbers and earth connections
It is bad enough that electricians might not understand what a network cable is. Plumbers are definitely worse. Common practice was to bond electrical earth to the nearest cold water pipe. My friend's workshop did not have a water pipe, so the earth wire went through the wall, and was clamped to a pipe in the bathroom. Everything was nice and sanitary, until a new sink and toilet were fitted in the bathroom. The plumber used plastic pipe. This disconnected the earth, so working on anything connected to the mains got a bit exciting.
The mains wiring in my friend's house was a bit unconventional. It is a Victorian house, that was once used as a doctor's surgery, which involved a lot of extra wiring. A typical extension for the mains consisted of a ball of insulating tape, with wires going in all directions. Stuff was connected to multiple fuses. An electrician came in and sorted it out as best he could. I don't think he suffered any permanent psychological harm as a result. Nobody died, which is always a good indication of a job well done.
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Sunday 22nd May 2022 17:30 GMT Man inna barrel
Breathing lessons for electricians
I used to drink with a couple of electricians who worked at a printing company, that had some hefty electrical wiring. The print works dated from the middle of the 19th century, if I recall. The wiring had kind of evolved since that time. One day, a steel wire armoured cable had to be disconnected. Three phase, of course. The breakers were opened, and the senior electrician proceeded to open the connector. He was crammed in a wiring cabinet at the time, with his assistant waiting outside. Said assistant noted strange noises coming from the wiring cabinet, along the lines of "Gkk! Gkk! Gkk!". The pair were inclined to lark about, so this might have been one of those occasions. Just in case, though, he pushed open the wiring cabinet door a bit. There was his colleague, looking very odd indeed, holding the two halves of the cable. There may have been smoke, but not as bad as the botched execution in The Green Mile. Anyway, the assistant found a broom, and pushed the cable away. The fried sparky was taken to hospital, and recovered, but with severe burns to his hands.
It was subsequently found that the earthed outer of the armoured cable had been carrying several amps of neutral current, and when the connector was separated, the two halves ended up across phases. You might presume that this should have blown a trip. That assumes that anybody actually knows what the wiring is, with various drawings going back over more than a century.
I was told later that the electricians had taken part in some health and safety training not long before. One module was "How To Keep Breathing When You Are Electrocuted", or something along those lines. It seems that was very timely.
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Sunday 22nd May 2022 19:51 GMT Stoneshop
Re: Breathing lessons for electricians
One module was "How To Keep Breathing When You Are Electrocuted", or something along those lines.
Back in my Field Service days I was sent on a month-long course on the VAX9000, in Galway where those systems were assembled for the European market.
The first two days concerned first aid and CPR: the power system involved 300V DC buffered by several Farads worth of elco's. Those were meant to bridge about 10 seconds worth of power loss, so at best some quick manual switchover.
300V DC is bad for your health.
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Sunday 22nd May 2022 20:47 GMT bigtreeman
phone line earth
A customer had some gear supplied by a competing IT shop. One of their special deals was disconnecting the building earth from ground.
Yes, floating earth, what fun.
When lightning struck, everything electrical in the office and their home was utterly destroyed. But the lightning also went down the phone lines and took out the local Telstra substation.
I found and reconnected the earth at the ground stake and thought nothing more till I found the same modification at a couple of other customers also supplied by this shop. They used to get quite a lot of storm damage insurance jobs.
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Monday 23rd May 2022 07:34 GMT Blacklight
Electrickery...
My secondary school had a lovely BBC Econet setup, with a variety of BBC-B and Master machines (ah, CUB monitors), across the whole school site (some fun cabling runs, mostly external). One night, there was a storm, and some well aimed lightning hit the Econet cable.
I remember the IT teacher spending the next few days soldering many, many poorly BBC computers.....