Electrocution? All part of the service, sir! The weekend is over and that means time for a nice biscuit, a hot beverage, and another tale from the vaults of Who, Me? Today's story comes from "Thor" (obviously not his name and a sign the Regomiser has watched too many movies in lockdown), the solitary member of the after-sales department in one of a chain of stores that …
"Today's story comes from "Thor" (obviously not his name and a sign the Regomiser has watched too many movies in lockdown)"
FWIW, Thor is quite a common name in Scandianavia, even (slightly) increasing in popularity.
And no, it's not connected to either paganism or superhero movies. People just like it as a traditional name.
Years and jobs ago, there was a fellow at one of the customers who went by "Artie", given name I suppose Arthur. His surname was in fact Scandinavian. One of our techies came back from a stint at Artie's shop to report that Artie now went by "Thor". This was said to be his wife's decision. I assume his co-workers were as amused as we were at the vendor's.
People do stupid things and it’s hard to be fail safe.
In a recycling bin in a controlled room an unauthorised person removes something to give to a customer.
Just as well they checked it in store.
Clearly a long time ago especially as so little regard for users data.
When my MacBook went in last year I had wiped it, I had to wait there while they reinstalled iOS 10 wiping the drive again in the process, took over an hour.
I lived a moment like that - and I was the one holding the power lead.
It was at the beginning of my career in Luxembourg, all those years ago (my daughter wasn't even born yet). Our company had just recieved shipment of a gaggle of tower PCs (they were for the training room that was being set up) and I was tasked with creating an application that required server access.
I needed a server.
I went to the head of IT and asked him if I could take one of the new arrivals to use as a server and he agreed. I went down and took one out of its box and brought it our corner office. I set up the requisite peripherals and went to plug in the PC.
POW !
Flash of light and short tongue of flame shot out of the PSU. The PC was dead.
What I didn't know is that the shipment came from the US. It was configured for 110V, and I hadn't thought to check that the tiny red switch on the PSU was in the proper configuration.
I went to explain myself to the head of IT, who was a bit miffed but told me to get another server. I completed my task, wiped the server from the machine and brought it back to storage.
By that time, all the boxes had "110V !" written on them in big red letters.
Ever since, I systematically check any new PSU or desktop box to ensure that it is in the right setting.
This presumably still happens today.
I haven't seen the magic 110V switch catching someone leaving in a 220V country, but I still today see plenty of kit meant to run in country X having power cords from country Y, Y being of course the country sending the kit.
This is because procurement people just tick one box in the ordering tool, without bothering or asking people on the field about those details. Some of them, located in country Y usually, not even knowing X or any other country has different power plugs !
Also kit arriving with no rack mount kit, fun fun :)
I'm not going to repeat the story of the user that decided to flick the switch, while it was operating & royally screwed the MBR.
Instead spent the Friday morning rebuilding a 24V PSU for use in a weather proof sealed box for use onshore/offshore, as it was a Friday we went to the usual lunchtime meeting, on my return I fired it up without checking the Voltage selector.......
You can guess the rest....if you can't here's a icon.
I still today see plenty of kit meant to run in country X having power cords from country Y, Y being of course the country sending the kit.
Along the same lines - I'm an engineering road warrior based in the UK but covering Europe and Israel with occasional detours further afield (Japan and USA mostly). Of course, for my laptop I was supplied with precisely one UK power cable, and told that was my lot.
Initial investment was in a travel power adapter which covered most options, but annoyingly Israel has two similar but not compatible socket sizes (different pin gap and widths). One works with European style cables/plugs, but the other is unique to them (or at least doesn't appear anywhere in Europe to my knowledge). And of course the adapter only has European option, nor t'other one.
So over the (too many) years I have "accumulated" something of a bag full of regional cables, as also some of our customers don't like us using travel adapters...
Whenever I travel abroad I try to get to a local flea market, or secondhand shop, to source the local power lead rather than mess about with adaptors that just want to fall out of the wall socket. Usually easy to get a C7/C8 (cassette), or C13/C14 (kettle) lead, the C5/C6 (clover leaf) can be more tricky to find. Occasionally you'll see the local Apple lead, I have two Swiss Apple leads for some reason, but if you can't find the Apple one, it can be faked with a C7/C8 lead.
One time I was in the US and had forgotten to bring an adaptor. Usually you can borrow one from reception, but it was late and the motel's front desk was closed. I managed to dismantle the bedside light and used the bare cord, with a couple of clothes pegs, attached to the pins of my standard UK plug to get my laptop charged.
I used to have a universal laptop power brick. It came with a range of adapters for the AC lead (which had its own, unique, plug for connecting to the brick) and a range of adapters to fit the majority of laptops around at the time (the adapters addressing laptop socket geometry and voltage requirement). It meant that whichever laptop I picked up for my travels, I had the right power supply already packed in my go-bag. I also had a case with a wide range of phone connectors (this being back in the days of dial-up); there was even one lead terminating in a pair of miniature croc clips - for those times the hotel phone was hard wired and the only option was to remove its case!
The other "fun" of course is American sockets. They are lovely small things, about 1/4 the size of UK ones (roughly double in both height and width).
The desks in our US offices are hot-desks (seating 4 people, two on either side), with two strips of 3 sockets along the middle. Works wonderfully for those with US cables, as they fit nicely and all three sockets can be used at once.
Of course a travel adaptor, especially a UK one with a UK plug stuck in it is somewhat larger and overhangs either one or both of the other two sockets and blocks them out.
Made a good excuse to be issued with a couple of US cables though by the local office, as I was lugging around two laptops at the time (my own company one and one used for customer training). The adaptor got consigned to use in the hotel room where there was an excess of sockets and no-one else to annoy.
Yes, the universal power and data adapters were almost a status symbol. My set(s) plus the huge collection of data cards and adapters for them made for a large case. PLUS the many connectors for desktop PCs and the hard drive cradles, meant my work backpack actually had its own gravity field.
Then the huge laptop with room for all the connections and forensic software plus data recovery kit…..
I loved and hated it but a couple of times when it got used “unofficially” to recover lost files that really mattered, then it got lighter. It was also a totally wicked forensics kit but that was never as nice.
Glad I’m out of the game, even switched to IOS to ensure I’m no longer a real techie.
From my research for a client, there is at least ONE country that has BOTH 120 and 240 and uses different plugs to differentiate. You could theoretically find both in the same room. No, I don't know why this is. It seems like a recipe for disaster for the unaware.
Pity the poor ignorant voyager to that country
From my research for a client, there is at least ONE country that has BOTH 120 and 240 and uses different plugs to differentiate.
It surprises me that it isn't more common, as having both 120 and 240 in the same room is quite common in about every residential kitchen and most laundry rooms in the USA and Canada. However, while we have both voltages the plugs for each are significantly different in design and not likely to be confused -- other than the NEMA 6-15 but that plug/outlet style is not common at all outside of industrial applications and I have NEVER seen one in a residence or office setting.
That almost-but-not-quite EU plug could be Italian. They have sockets with a slightly different offset and i think slightly smaller diameter holes, such that it looks fine, but takes you a while to work out just why you can't force your pins in the holes... Not even lube does the job!
They seem to have both types of sockets installed in (probably? older) buildings, so you just need to hunt around till you find one that fits.
"not even knowing X or any other country has different power plugs !
... or even different fusing arrangements. My pet hate is that we order a 'UK' variant of a product and it does arrive with the expected BS 1363 / IEC 60083 'G' plug on the end...but it's almost always fitted with a 13 Amp plug-top fuse......which is usually totally inappropriate to both the power rating of the related equipment AND the size/capabilities of the cable between said wall plug and the device it connects to.
e.g. incoming product is a 120W DC-DC Converter, and the supplied 13A plug-top fuse would allow at least 3KW down the flimsy small-CSA wires attached to the before popping - and that's assuming the fuse DOES rupture at 13A, and the wall voltage is 240V (Hint:Neither is true in the UK, and not just because of the bloody awful 'final ring circuit' idea)*.
Fitting inappropriate fuses in UK plugs is an accident waiting to happen, as most people aren't aware of the correct rating. Personally, I'd prefer the 'default' fuse rating to be only 3A, i.e. on the safe side. Still, I suppose we're better off than the parts of the world that use un-fused plugs (This isn't a pop at the US electrical plug etc, but it's a good critique of the issues involved:-) ].
* Ones personal preference with current technology: [1] RCBO per-circuit in the panel, dimensioned for the circuit purpose, [2] All circuits are radial (As in the U.S., but that would be unpopular here in the UK) and [3] All plugs/fused spurs etc fitted with individual fuses (As in the UK) to suit the 'to-load' cable.
Swing and a miss there from you
Current regs on what used to be called pat testing (now In service inspection and testing of electrical equipment) mandates 2 fuses only 3 and 13 with an exception for IT kit at 5amps.
However fuses are virtually pointless as frequently a 32Amp Type B MCB will trip before the plug fuse fails.
Fused plugs are only required as we run 32Amp ring finals instead of 16 or 20amp radials as we did pre WW2 and most of the world still use (saving copper), Ring finals bringing their own hazard - get a break in the ring and your wiring is now underrated for the MCB/RCBO installed.
Years ago, before education services had corporate IT to install new kit (or indeed networks) I had to receive boxes and connect up new PCs. I was lucky, the first time I did this, to notice that there was a rocker switch with 110/240 positions -and it was worryingly open to accidental pressing- albeit with a bit of pressure, perhaps. It was OK, but after that I always checked new PCs. And on two or three occasions the rocker switch was set to 110. And one was just rather less firm than I'd have liked ( and more prominent). I've experienced the latter on a home PC too - and some other items as well if my memory serves me correctly.
It goes onto my mental list of *stuff that shouldn't ever happen but probably will*.
When I was working at a Technical Publications company in Birmingham, before I was promoted to Deputy IT Manager (long story, see my comments elsewhere), we had several new desktop computers delivered. The then IT manager plugged the first one in and - BANG - the voltage switch was set to 110V. He then checked all the others, and about half of them were set to 110V and half to 240V, so it was mere chance that he had discovered one of the 110V ones. Some time later, after I had been promoted, we had some more computers delivered, so I checked the voltages, again 50/50 high or low voltage. I set them all to 240V and applied a strip of insulating tape to the rocker switches to ensure they would never be accidentally reset to 110V.
Had the same issue... made it part of our installation process/checklist to set the switch to 230V and apply a dollop of hot glue in the now vacant cavity on the 115V side to prevent moving the switch back easily.
Still could be done by poking the glue out with a small screwdriver if ever needed but as that took several minutes to do no idiot ever tried.
I also check old stuff bought off eBay or donated by friends. I've seen stuff that had the rotary plug type setting set to 200 or 210.
Some stuff is 220V only and very occasionally has underspec'ed mains transformers so needs a series resistor even for our 230 V.
Electricity (before Brexit) was harmonised across the EU to 220V. But actually they just gave everyone new tolerance limits and the UK had the biggest + limit as the UK nominal 240V can be 245 V.
Modern SMPSUs can work maybe 80V to 260V, though labelled 110V - 240V. They might even try to run at an even lower voltage. But if it's 500W the 2.1A at about 235V to 245V becomes maybe 5A during a brown-out. SMPSUs are a different problem to old AC/DC gear that half wave rectified the direct mains, or tube lamps with no PF correction cap to the Electricity Grid, as reducing the supply voltage a little increases the current load.
Safety googles.
Harmonised nominal voltage is 230 NOT 220 and +10/-6 with a view to +10 and -10 but as yet not done.
Essentially meaning no one had to change any transformers etc
In an installation your voltage varies depending on how far you are from the substation, right next door you can easily see 252 volts, my own is 245, loading is also a factor, in times of high demand the supplied voltage can drop
I too have blown a power supply with the 110-240V switch. The computer was misbehaving for some reason and I decided to try a proper cold start by shutting it down and turning the power off and on again. The previous machine had a physical on-off switch next to the power cord. I located the switch on this one by feel, but there was no power switch, only the 110-240V switch. My subconscious was too stupid to ask "Why is the switch so small?" Bang!
I recall the time I was working on a PSU for something. I had it out on the bench, upside down whilst I was diagnosing. I don't recall if it was a scope or multimeter I was using but what I do remember was that just as the service centre manager walked in with some potential new clients in tow, giving them the grand tour, the caps on the PSU chose that exact moment to go bang.
Bizarrely I didn't even jump. They did though.
And then after about a second of silence, the manager pipes up "And of course anything we can't fix, we just kill".
I was once asked to deliberately fail a small, line-powered consumer device.
We set up a video camera and recorded the flames.
A fun time was had by all, and it was a hit at the weekly staff meeting as well.
The "essence of Ohmite" dissipated after an hour or two. We made no friends in the office area adjacent to our lab.
Miss out on all this fun. Connecting a PSU set for 240v to a 120v volt source tends not to produce much in the way of fireworks, though I suppose it may induce some head scratching as to why things don't seem to be working.
Most PSUs these days seem to be 100-240v auto ranging, so hopefully this is mostly a thing of the past for you guys.
110V ? -- I'll raise you 415V .... quess what happens when someone connects up a 3-phase genny but an error is/was made - how long do you think 240V pc power supplies last when 415V is applied to the office UPS ring main?
Clue --- ? ---- not long but slightly longer than the sparkies job ......
Worked in a building in Paddington where the local 'leccy board managed to connect the building's supply across 2 phases, so again 415V.
AFAIK most of the kit survived (it all did on our floor) but we did spend a lot of time (and petty cash) traipsing up and down the Edgware Rd buying up their supply of various fuses
(this was back in the day when every other shop on that stretch of Edgware Rd sold electronics of one kind or another)
I once changed the power supply in an Amstrad 2286, onsite, in front of a customer. That involved taking the machine completely to pieces, removing the power supply, opening the cover for that, remove PCB, unsolder mains cables, solder cables to new PCB, re-install and put back together. Not a particularly hard job, only took a few minutes and the gas powered soldering iron worked nicely. It was only when I went to plug it back in, I discovered the mains cable had been live the whole time.
A few years ago I was removing the ballasts from the kitchen lights at my parents' house so they could be replaced with LED tubes. I turned on the light, then because the panel is unmarked started flipping breakers until they told me it went off. Good to go, right? Not so fast!
When I started clipping away with my wire stripper/cutters I got a big spark. Left a little indent in the clippers on that spot that remains to this day as a reminder to me.
I remembered those lights can be controlled via two switches, though the switch in the dining room is never used. I flipped on that other switch and the remaining fixtures lit up! I went back to turning off breakers and found the second breaker that powers the lights. I wasn't even aware that was a possible configuration, and to this day have no idea if that's to code or was a wiring mistake when her house was built.
"When I started clipping away with my wire stripper/cutters I got a big spark."
As I mentioned before, I always religiously follow the instructions in the procedures of one of my customers "Every point shall be proved dead before undertaking any work at that point."
Has proved to be v good practice.
>...required two breakers to be turned off before it was dead.
An electrician friend worked at a large print works, that dated back to Victorian times. The wiring was a bit eccentric in places. He had to disconnect a steel armoured cable, inside a pokey little wiring room, that only had room for one person at a time. All the breakers were off. Good to go. But there was a neutral fault, that meant load current from somewhere unknown was flowing in the steel outer, which should be earth. As soon as our mate separated the connector, he had full voltage across his hands.
At this point, he was paralysed, and could not even cry out. He managed a sort of croaking noise to alert his colleague. Initially, this colleague thought that the strange noises were just his mate larking about, but then he took a peek round the door. He found a broom to knock away the cables. Luckily, our partly cooked electrician had been on a safety course, about how to breath when being electrocuted. (Was there a practical test?) He did end up with severe burns.
Anyway, at least our hardy electrician was not "proved dead".
An old story from BBC Llandaf.
Studio 2 was an 'audience studio' - big area, floor stepped down several times to accommodate a studio audience, with a central area some 5-6 metres below the lighting gantry. The gantry had multiple live rails to allow remote repositioning of lights, all isolated by a breaker at the studio door.
Sparky is up a scaffold (can't use a cherry picker because of aforementioned terraced floor), replacing the drive motor on a steerable light, when he reaches a little too far and topples his scaffold.
Being a sparky of great brain, he grabs the nearest support - a thankfully isolated live rail, and begins to call for assistance.
Passing Production Assistant (velvet jacket, beard, pipe, zero clue) hears the cries and rushes to assist.
"Who's there?"
"Electrician. Help"
"Where are you?"
"I'm up here"
"Sorry, can't see a thing. Oh, here's the light switch"
I understand Sparky's response went along the lines of "That's not a light swi - Screech!" <thud>
Sparky survived, but could never bring himself to trust production assistants after that.
And this is why we have the five rules:
1..Isolate
2. Lock-out/tag-out
3. Measure voltage
4..Ground and short
5. Cover or remove nearby parts that remain energized
I carry a nice homemade tool: A plug wired to short all three pins together. After making sure the breaker is off and my circuit is dead I'll plug it in to make sure it stays dead. Had one too many case where a helpful person ignored my tag-out. I "can* wire a socket under power if I really must but if so I'd want to know, thank you very much!
I had the same up north. Some dickhead had constructed a lighting ring going out of one breaker and back into another. Luckily I have a sixth sense for that kind of thing. All the hairs on the back of my hand stood up as it neared the relivened bare end of the wire.
I have seen similar. I was relocating boxes and placing box extenders for a wall insulation upgrade project. One outlet would not die no matter which breaker was turned off. Of course it was an un-relocatable box requiring an extender which required un-wiring the outlet and most of the time wire nuts and extra wire. I did that one live because I was now holding up the drywallers, fortunately it did not need wires extended so no striping of live wire .
Later on in the job I was doing some other electrical at that house and found another zombie circuit which just wouldn't die. This time I could do proper troubleshooting and circuit tracing. I then changed my mind that these were not zombie circuits when I found that they went dead after turning off two particular breakers. I then thought of them as Siamese twins. I found their connection point in a junction box and performed a successful separation surgery. Although due to space (and budget, of course) constraints, I could not provide them with separate junction boxes. I did however thoroughly label each circuit in the junction box and wrote a warning on the cover with both circuits identified.
When doing the outlet, I was tempted to use a technique I was taught when installing payphones at convenience stores (some of the worst wiring I have seen). The senior payphone installer who had previously worked for GTE had a special flat screwdriver which looked like it barely survived WWII with multiple wraps of electrical tape halfway up the shaft and around the handle with a tip and lower which obviously had been reformed by electrically induced explosive disintegration. When the proper breaker (or fuse) could not be found, it came out of the toolbox and was jammed into the box to short out the circuit. It worked most of the time. Once in what must have been fairly loaded or unevenly loaded panel the main breaker tripped. Another time no breaker tripped and senior tech had to rip the welded screwdriver out of the box, we buttoned back up the box and told the manager to get an electrician in to fix the issue. Convenience store managers generally do not like it when you turn off the store lights and really hate when you shut off the fuel pumps or cash till when you are trying to find the correct breaker.
Mid 90s, I was doing a house re-wire as a favour for friends of my now-ex. The previous occupant of the house had done some 'interesting' modifications to the electricals, such as a pair of thin "bell wire" wires sticking out high up a wall, with a label "for clock" attached. (Judicious testing identified them as live, so I went looking for the source. Under the floorboards of the bedroom above, the ring main cables had been stripped back to bare copper, and this thin stuff *wrapped around them* then the boards replaced - nothing to secure the joint, no insulation, nothing...)
To try and make sense of this mess wasn't going to fly, so I was replacing everything. That evening I was in the kitchen and had already pulled every fuse bar a 32 or 40A fuse for the cooker - the cooker had one of the old isolation switches with a regular 13A socket built in, into which I plugged a table lamp to get some light. I'd been working my way around the kitchen pulling the old sockets and just cutting the wires behind because they were not going to get reused. Got to the last socket, squeezed my cutters, and got a large flash of light, a loud bang, and total darkness as the lamp went out. Followed by a hesitant "are you all right?" from the freshly terrified woman who had been watching from the doorway.
Bloody idiot had only wired that socket into the cooker circuit! I was fine; cutters had a decent insulated handle, but they now had a nasty gash out of them, after passing god knows how many Amps at 240V, before the fuse blew, and were pretty much ruined.
I'm especially careful these days!
I have told this story before, but it seems appropriate here.
When I were a little lad, I found that I could strip wire better with my teeth than I could with wire-strippers.
One day, when I was about fifteen, I was working on wiring up something - don't remember what it was. I stripped off a piece of mains cable in my usual way. I was holding the cable, and the two bare ends touched each other - there was a helluva bang, my hands were covered in carbon....and I went into a cold sweat and my heart started going like a trip-hammer when I realized that the other end of the mains lead was attached to a plug, plugged into the wall. And I'd put the wires into my mouth....
It's a miracle that I'm still here to tell the story. I still get slight cold shivers thinking about it, even though it happened fifty years ago.
I have a similar tale, eerily similar. Mine also occurred about 50 years ago. I was somewhere between 2 and 3 years old at the time. My mother had just finished ironing clothes. I was being helpful and wanted to unplug the iron from the extension cord. I could not quite muster the strength to separate the two cords. So, I decided to use two hands pulling in the same direction on one cord and anchoring the other cord with my mouth. I still to this day have a memory of the sensation but not immediately what followed. I also have a scar at the right corner of my mouth where the wound separated my lips.
The fearful reaction was not mine but my mother's. She must have had a brief micro heart attack prior to yanking the cord out of the wall. I can only imagine what speed records of all sorts were broken in her goal to get me medical care.
Knew a science/math teacher who had morphed into 'the computer guy' back in the day. Much to his disgust, the main use of PC's in the school was to teach typing.
So the typing teacher walked into the 'business studies' classroom, switched on the first computer and *BANG* it died. OK, that was loud, but she recovered and bravely approached the second computer. *BANG*, it died. That made her even more edgy, but *BANG* and *BANG* This is not a technical person: she's a typing teacher and this was the 1980's. She approached my friend severely shaken and almost in tears.
Unknown student had switched all the computers to 110....
"Unknown student had switched all the computers to 110...."
Mustive been before it became standard practice to drop potting compound on the switches to prevent exactly this happening.....
(At least, that's what was done in schools I dealt with. Didn't stop 'em unplugging the network cable or stealing mouse balls)
Had a kid do that, removed the RAM out of the machine I was fixing.
Called it to the teacher, when I noticed it as this was the school for the more feral children in Somerset, the pupil was summoned back, which was a shame for him as he was almost home........in a taxi 10 miles away & so had to return to school, to point out where he had stashed it for later retrieval.
As a child, I had a bedside lamp. It was an electric lamp with a plastic push button switch on the domed metal base for on and off. Anyway, I managed to break the push button on the switch, but discovered that the (metal) key to wind up my old toy train would fit and could be used to turn the lamp on and off (you are way ahead of me by now, I expect).
Anyway, comes the day when I am switching the lamp on with one hand and touching the base with the other.
Nice circuit. I could feel the electricity pulsing up one arm, across my shoulders and down the other arm. Fortunately, after a second or so, the current also provoked a twist in my torso. No harm done (I think).
I am such a clever boy!
I think I had my first dose of mains at age 4, playing with the radio, apparently by touching the pins on the mains plug pulling it out of the socket. And while the city we lived in back then had been distributing 127V, that was changed to 220V a few years before I was born. But it appears I have a very high skin resistance; even with today's 30mA GFCIs on every domestic circuit I occasionally feel that the wire I'm touching happens to be live, and they don't always trip (which they do without fail using a certified tester).
Doesn't seem to have harmed me. Neat party trick though, making a bulb glow just holding it.
Twas either a paperclip or nailfile for me. Age about 6.
Lesson learned (mostly). I can think of two recent events where I got lucky, though. One involved a GFI tripping, fooling me into thinking the circuit was dead (it had been live when I started futzing with it) and another where I cut into a cable which was no longer used, and tripped the breaker.
No matter how careful you are, mislabeled breakers and poor assumptions can kill you.
Not an electrician, but almost...
When I was very young (back in the 70s), I was fascinated by how the world worked, constantly pulling things to bits, trying to basically reverse engineer everything. (Much to the annoyance of my parents, as I sometimes also disassembled things like kitchen appliances and other items that were actually in use in the house!)
Electricity seemed such a mystery to me at the time, how can energy pass through wires! Pipes with liquids, levers, rotating shafts I understood, but a solid wire, how can anything get through that!?
One day, I was about 6 I think, in my bedroom, with my trusty Meccano screwdriver in hand (which were solid metal back then, and you can guess where this is going now), and a few bits of wire I pulled out of something, I decided to investigate.
BANG!!! Me now sat on the other side of the bedroom floor, some distance away from the now slightly blackened smoking mains socket where I'd been a moment earlier, with screwdriver still stuck in the live hole. Parents rush in, see me motionless, thinking the worse. At that point I apparently just started smiling, wide eyed!
After that, I regularly got donated electrical items to experiment, sometimes to try and fix (radios etc), electronic kits for Christmas way above my age range etc.
After leaving school some years later, where I'd focused on the sciences, especially physics, I went on to study Electronics, then got an apprenticeship at a local firm, later becoming one of their Electronics engineers for a few years.
In my 50s now, and I still want to know how everything works!
Decorating my bedroom with Fairy Lights bought from a jumble sale, I'm not sure how old, but before I was ten.. Got several shocks from those before I learned to be more careful! One doesn't initially realise that even though the bulbs are rated at 12V or whatever, break the circuit, the ends are at the full 240V!
I had a high school science teacher who did that in front of the class. He was doing some sort of demonstration using a 12v car battery and someone asked what would happen if the two terminals were connected. He says "let's find out", then holding the insulated end of a long screwdriver lays it across both terminals. Nice shower of sparks and the screwdriver becomes a permanent fixture of the now deceased battery. He got out another battery and continued with what he had been doing.
He loved doing "shock value" stuff like that. He had replaced a teacher that was there for close to 50 years, who had a storage room full of all kinds of weird stuff. Sometimes he'd bring something out, and him along with the whole class would try to figure out what it is for. One time he brought out some sort of metal thing, that was threaded to connect to the gas line on the bottom with multiple holes on the top. He hooked it up, turned on the gas and lit it, but nothing happened. He couldn't understand why there were no flames coming out the holes. He messed around with it, sort of pressing his fingers against the holes - then all at once a big flame shot out and singed all the hair off his arm and left big black marks on a few ceiling tiles. Sometimes I wonder if he made it to retirement age lol
He let us "learn" the hard way too. I recall the class doing some sort of experiments involving a little plastic device meant to connect to a 9v battery - some sort of wave generator. My lab partner and I wondered what would happen if we connected it to 120v, and stuck the two wire ends into the socket. Found it goes very fast for a very short time, then creates an amazing amount of nasty smelling smoke. His response was to yell our names so everyone in class knew who to blame for the impromptu stink bomb, open the windows, and give us a replacement plastic device to continue the experiments we were supposed to be doing.
Another time he found a vial of mercury, and gave us all a little blob to play with. We were pushing it around with our pencils/fingers on our desks, for the rest of the year (and probably for years after) the desks had tiny bits of mercury in them that had been lodged in the deep cuts from years of graffiti in the ancient desks.
One of the most fun teachers I ever had, and you'd learn a lot though he'd never be allowed near children these days for fear of lawsuits!
I used to have a multimeter. Just the fairly small average type used in electronics generally. But it did go up to 500VAC. I frequently used to stick the probes into a live IEC lead from "dead" PCs as a quick'n'dirty test of the cable, plug and fuse. Right up to the day that there was a bright flash from inside the meter. The internal glass fuse had almost disappeared. The glass was a fine dust and the fuse wire had vaporised, leaving the inside of the meter case all around the fuse with a nice shiny metallic coating. The meter is now pining for the fjords.
Ah... chemistry!
We did stinky stuff (like making soap from animal fat we got at the butcher's... it was already a bit off when we started), boom-y stuff that left a 1.5 meter crater in a classmate's field, and actually some sciency stuff like a Stanley Miller-Style early earth atmosphere experiment with automated sampling hooked up to the school's ancient gas chromatograph. That was actually quite involved for a high school project in 1983 - had to build some hardware, no Arduinos around at the time so we built a custom interface for the Apple II, borrowed some servos from the RC model Club as our actuators etc. It even worked reliably for the 6 weeks of the experiment.
> If you drop a spanner across the power busbars for one of those it will vaporise with a bright flash and a loud bang, leaving each end welded to conductors.
Someone did that in the battery room of a telephone exchange. It may only be 48V, but the prospective current is in millions of amps. In this particular installation, the busbar supports had not been specified correctly. The magnetic field produced by the fault current pulled the busbars together until they shorted. Now were looking at some current. Imagine bank after bank of 2V lead acid cells, each the size of a filing cabinet, all boiling and gassing.
We made a monitoring device that was powered at either 24V DC or 110V AC via different terminals.
It was not unusual to find both supplies wired up and live, at least until the unit was found to be 'not working'. Repair was a simple fuse replacement, but involved dismantling the monitor (and supply correction, drawing updates etc.). It was a silly arrangement, updated devices were 24V DC only.
Many years ago I worked as a service tech at a PC reseller. One of my colleagues had a low-volume but repeat customer that he was very fond of. She travelled a lot to exotic places, and often needed some new bits and bobs to go with her. I can't remember now if she was a filmmaker, a researcher or something similar, but I guess that doesn't matter. Her main work computer had died on the eve of another trip to rural Africa so she called my colleague, frantic, at two o'clock in the afternoon. Luckily, our distributor had exactly the desktop PC she needed in stock, and he managed to swing express delivery to our store that same afternoon. He'd then come in early the next morning to set everything up for her so she could pick up the new machine at 9:30, literally on her way to the airport. The customer was very happy and my colleague was on an adrenaline high from the excitement.
Cut to next morning, I arrive to the office to him sitting with shoulders slumped, his head cradled in his hands and the faint smell of burnt electronics still in the air. In the process of getting everything ready, he'd unpacked everything, installed the extra memory bricks, hooked everything up, for SOME OBSCURE REASON flipped the power supply toggle switch to 110V and powered the machine on... This wasn't a case of "sometimes they come off the conveyor like that", he remembered actually flipping that switch but couldn't say why he'd done it. It was just a true brain-fart moment.
Against the odds, I managed to pull some strings with the distributor and arrange another express-and-beat-rush-hour-traffic-into-city-center delivery of a replacement power supply and get it replaced (he didn't want to do it himself, for some reason...) just in time for him to pack it up for the customer who jumped out of a double-parked, waiting taxi outside the store. I was on a bit of an adrenaline rush myself that day. All's well that ends well, the customer was very happy; and I doubt he ever told her about his mishap.
So the thing is...I've done this by accident when I was living in the middle east. Yes, it blew out the fuse on the 110 circuit. But what I found in my case was, the 220v circuit still worked fine (for many years in fact). So if you are in this situation, it's worth checking...not that one should give a customer a computer like that.
User gets nice shiny new desktop PC.
The next day, we get a call saying that it has gone bang and all the lights have gone off.
We advise unplugging it from the wall and calling the electrician and I went down for a look as I had delivered it the day before.
Apparently the manager had slid the switch on the PSU from 220 to 110 (or whatever variation of those numbers was current) to make it use less power and save money!
When I got there, she was wondering whether it would be a good move to slide it back before IT figured it out. The workers told me anyway as it was funny!
Impressively, Dell gave us a replacement! I note that these sliders do not show on the back of their computers now.
I can't recall seeing a voltage selector switch on a PC that wasn't a recessed slider that you needed a screwdriver or similar for to change it. With some other electronic gear it could be an insert that you could only remove and put back another way with the mains lead removed, and a lot of audio gear up until the time they started using SMPSUs (blergh, retch) had a rotating switch on the back, with a slot that you needed a coin for to turn it.
An exposed toggle or rocker to select the input voltage looks pretty stupid to me, but as we all know, the computer industry is not above even extremely stupid stupidity.
And that's sometimes even true.
I've been working on live circuits before (yes, that's commonly done here) and accidentally touched a live wire, realizing that I'd done it only after I'd noticed a slight tingling sensation in my hand and looked at it. But that's because I was only weakly grounded, 120V is definitely enough to cause damage.
And just as a reminder, the US is in fact a 240V country. We use a split-phase system, and phase-to-phase is 240V. You didn't think we used 120V for water heaters, HVAC systems, stoves, clothes dryers, and car charging (ok, sometimes we use it for car charging, but only when a 240V circuit isn't convenient) did you? And we've typically got more of it, a typical American home has 200A available at 240V.
Here in Germany, 3 phase 400V is standard (230V phase to ground).
Residential circuits are usually 63A per phase.
High-powered equipment like ovens, ranges and water heaters (air conditioning is still rather uncommon) get 3 phase, everything else gets 230V, usually 16A per circuit.
The 3-phase circuit comes in handy to set up a fast charge wall box for electric cars as well.
As much as I really, really hate to quote Wikipedia, electrocution does not imply death: https://en.wikipedia.org/wiki/Electrocution
"Electrocution is death or severe injury by electric shock, electric current passing through the body."
It was chosen as the word to use for death in the new fangled electric chair by the US. Overuse of which has distorted the original meaning.
A quick look at the first half dozen or so Google results shows the majority agree that the meaning of electrocution has evolved to mean death or injury by the passing of electric current through the body, not just death. This includes the Oxford English dictionary. Most also define the origin of the word as described above in another post,
But for those who do have a shore based mains and an inverter you have a very spectacular way of converting your boat into a liquid asset by connecting both shore power and inverter/generator.
Icon though I doubt it would mange to reach those proportions most of the time.
Sledgehammer that thing. I've had too many people fish stuff out of the bin and try to use it, if it wasn't obviously broken.
Then they bring it to me to fix AGAIN, and I recognize a scratch on the case or something, and go "wait a minute, I trashed this last week!" after wasting time on it again.
Yes, some people are very like that. I remember having a laptop sent for a hardware issue which couldn't be repaired, so I removed the disk to properly erase. While I was in there, I also disassembled several other pieces of the system just so my colleague (I know who you are but you don't so you can just assume it's not you) wouldn't try to repurpose it. We had had a problem with use of broken parts and another problem with people not understanding how to decide whether the extra memory on the shelf could be used in any given computer.
Posting anonymous if the colleague reads this (I'm guessing not) and actually does know who he is.
Happened once to me. I was invited to a hackathon in Redmond (you can guess the company), and because I was then as much against using Windows for software development as I was now and laptops weren't a thing (this was mid '90s-ish), I carefully put my favorite box - a DEC AlphaStation - in the middle of my suitcase, checked it in, and prayed that the fancy new Alphas were as well bit as the old VAX machines. Arriving at the site, we were helped to an office, I got a loaner keyboard and monitor, an Ethernet connection, and then turned the unit on - nothing.
Slapping my head I turned the power off again, moved the selector switch from 220V to 110V, and everything came to life. Two weeks of hackathoning ensued before the workstation was put - now padded by dirty instead of clean laundry, but just as safe - back in my suitcase and I flew back to Europe.
You know, I'm not even gonna bother with explaining what happened next, y'all are smart enough. Let's just say that DEC replaced the power supply under the repair warranty even after I explained why it sorta exploded :)
I'd like to see anyone coming up with a policy like that electrocuted.
WIPE. THE. DRIVE. AND. REUSE. THE. HARDWARE.
Intentional wanton destruction of serviceable equipment should be a criminal offence. It's absolutely inexcusable. I'd suggest it should be a fine for any employee doing it, and prison for the manager who came up with the policy.
I worked for "One of the world's biggest computer companies" - they all say this don't they. Anyway I was put in charge of a new banking terminal installation which was the only one in the Europe. They started to get comms problems so I decided to change the motherboard in one. I was given the only board available which had been shipped to us from the USA and went to install it. I had forgotten that the board also contained an on-board power supply.......
Cue a good telling off and a long wait for the replacement of the replacement.
To save time and money on finding the right type of cord, outlets were ALL standard flat 110V Edison plugs, regardless of actual line voltage which could be switched(yes with a toggle switch) to 220V for testing of EU units.
Many times, when they switched from putting together 220V units back to US standard units, someone made the understandable mistake of plugging a 110V unit into the 220V power supply. A loud pop or two, and the smell of rancid fish oil let all know who had blown out the caps in the power supply again.
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