The unofficial guide to electrocution (and how to avoid it)

Contrary to the misguided belief of various safety authorities, many maintenance workers do often have to work live while troubleshooting faulty equipment. That's because a control fault can literally disappear when equipment is unpowered and be very difficult to trace or replicate in an isolated/disconnected state. Try to think of it as proofreading a safety document with your monitor turned off. LOTO (Lock Out Tag Out) has its place, but is not a blanket option. In the past electrical training used to involve a 4 year apprenticeship with an experienced tradesman working with you to show you how to do the job correctly and safely. That physical training was supported by thorough theory training, with actual electricians who would repeatedly drum safe working practices into the classes. (Including knuckling connections as a final check.) That was then tested with proper exams that showed you really understood the work. If you failed the exams you didn't progress until you had proven you understood the theory. While traditional apprenticeships are still happening, a rather horrible business of crash certification of labour with short slideshow presentations and "open book tests" (the answers are in front of you) has allowed organisations to bypass proper training and replace it with what are basically liability transfer certificates. Aside from instilling a completely false sense of confidence in unskilled labour, these certificates actually seem to be accepted by the safety authorities as proof that the victim was "trained" and should have known better when a fatality/injury occurs. Some of these short training presentations try to cover themselves by declaring that they are not a replacement for formal training. Others brazenly announce that no previous knowledge is required for their one day "safe electrical isolation" courses. Some of these courses are used to certify casual labour in a single day to do work on outdoor electrical equipment in a wet environment. When such inadequate training is given it puts the operative at risk, the public at risk and poses a huge hazard to other workers who may have to work on dangerously miswired equipment.

Building site working can be highly dangerous as well. I had a friend who was an electrician who frequently worked on building sites. This was about 50 years ago when safety procedures were not so strict. One day he was asked to wire up a transformer at one end of the site, so he removed the fuses at the main substation at the other end of the site and started work. Having made a couple of connections he suddenly noticed that the transformer had started humming! Fortunately for him he was not touching anything live at the time. He went back to the main substation to find that the fuses had been replaced. When he asked the foreman the reply was "Oh I thought you'd finished so I put them back". So he decked the foreman and walked off site. There are two lessons to be learnt from this. 1) Put the fuses in your pocket, don't leave them where some idiot can replace them. 2) Don't work with idiots.

Well, this is odd timing. My cousin just passed away today from being electrocuted by 7kV overhead mains while tree trimming several months ago. He was the only known case (here in the U.S. by Mayo hospital anyway) to have initially survive such an injury. He was finally what seemed to be on the road to recovery in recent weeks, but in an instant today, he was gone without warning. Very very sad. Being an electrical nerd, I always understood and respected the dangers of electricity and would usually wear gloves when dealing with anything that could be considered dangerous. Well after that wake up call, I now wear insulated gloves ALL the time, unless I 100% know there can be no power to it, or have tested the circuit for power multiple times. Don't risk your life! The slight inconvenience of finding some PPE and double/triple checking that the circuit isn't live is worth it.

Clive I have been an industrial Electrician for 31 years, and that was an outstanding explanation of Electrical Shock. I was aware of most of what you went over, but your way of explaining it really drove it home. Well done!

I found this to be much more helpful than any of my employer's safety training sessions.

I worked 40 years as maintenance in a factory. "Expect the unexpected " is the best advice I've ever heard.

Absolutely brilliant video Clive! I was a maintenance spark for 21 years in a brewery where lots of the gear was in wet conditions. The advice given to me from the 'old guy' I worked with, then replaced was: Don't wear rings, metal watch straps etc. Inside panels where they were live, left hand in pocket as much as possible. Right hand keep palm towards you as much as possible (or the other way around if you were left handed). Don't have anything sharp aimed at you in your hand that you will stab yourself with if you get a shock. Screwdrivers etc. When you know it is isolated, assume it might not be. Must have worked - I survived.

50 + years working around electrical stuff. I've never been shocked when I did things the "correct" way. Every time I received a shock I was trying to do something faster or the "easy way". Never work on anything live and all ways consider everything to be live. Test the tester, test and then test the tester. Everything you've said here is true. Loved it.

That was hard to watch I wont lie. When I was 9 my 17 year old brother was electrocuted whilst mopping the floor in a fast food restaurant. He had just handed in his notice and was working one of his last few shift before he went to university. the faulty equipment had been reported as shocking multiple members of staff, it couldn't be switched off at the socket immediately as the socket was 8' up a wall above a freezer, The plug was also incorrectly wired. I had a fear of mains voltage for most of the past 23 years but in the past few years I have watched alot of Clives content, some I found hard to watch but I wanted to learn more about mains voltage, I'm not going to say I'm not afraid anymore but I feel better for understanding it more about it. Thank you Clive, keep up the amazing Content. 👍

I was helping an electrician in Liverpool look at a supply to a lift. As he opened the three phase DB door there was an almighty bang and he shot past me at a hell of a rate. His fingers were a bit black, but in general he was ok ... probably needed new underwear. Turns out someone in the office next door had complained about noise from the control cupboard, so some genius had found out it was the DB door rattling when the lift was in use ... so jammed a handy bit of lead flashing in the top of the door. When we opened it, the lead fell straight down and bridged all phases, dead short to the case. The lead vaporised instantly and luckily the door shielded my friend from the molten lead shower. Managed to blow the main fuse to the building, so that was some amount of current!

"If you're in a confined space, that's where your body may be found." That sounds like a truly awful death. Thanks for putting this information out there. I've had a few really good shocks in my life and they are extremely unpleasant. I am fine working on almost any system in my home except electrical. I'll do simple things but I'm too clumsy to trust myself with rewring and things like that.

I’m absolutely positive this video already has or most certainly will save lives of technicians who watched this.

In my first industry job (working on broadcast equipment including tube based broadcast transmitters) our boss created a culture of not being macho about electric shocks. He would stop anyone he caught bragging about how many or how severe a shock you had received. His point being that no one should be working so carelessly or incautiously or unaware that they would put themselves in a position to recieve a shock. Given that we were regularly working on 1-2KV DC power supplies, there real was no margin for error in his mind. It's a lesson that has stuck with me all these decades later. Some of the guys I work with now think I'm being needlessly cautious, but I still haven't received a significant shock after over 35 years in industry.

The only big shock I've ever had, I was 12 years old, on a friend's farm. Conventional wisdom dictates that barbed wire fences aren't electric, and if you tried to hook a fence energiser up to a barbed wire fence, it wouldn't work so well, because of the higher resistance. I don't know whether this friend's dad was just a dickhead who'd wired the fence to mains, or if something had gone wrong that caused this, but for some reason, a barbed wire fence was live. I went to climb over it, I put both hands on it, because you generally don't want to risk snagging your crotch on barbed wire, and I just got this massive whomp through my chest. I had yellow tracks of bruising, presumably burns under the skin, going up both arms and across my chest. It took a good ten years for me to get over a near phobia of touching anything that might be live.

Fortunately, I've only had a few shocks in my life, these were in my teens, I'm 65 now. One I was moving a piece of equipment, and both hands locked, had to drop from my knees to fall to release the connection. The other major one was also unexpected, the web of skin between a thumb as fore finger dropped into the earth connection on an old school long Tektronix probe, then a finger on the other hand made contact with a 240V part of the circuit. Once, two of my technicians were working on some 3 phase electronics on a bench in our lab and the managing director brought a visitor through. Later he called me into his office to dress me down as he didn't like the fact that my techs each had a hand in a pocket, he said it didn't create a good impression. He changed his tune when I explained that if he wanted them to not keep a hand in a pocket he potentially could be responsible for a death if an accident was to occur.

Thank you for the reminder. I'm an electrician and I work in a factory, mostly I isolate before work, but when troubleshooting stuff that's not working there's no choice but to work live. Spending twenty minutes on your video was twenty minutes thinking about my safety, more thought than I give most days. You've reinforced my learning, and I hope I haven't been careless, but I think I'll be more careful in the coming days and weeks than I have been for a while. Perhaps I should put a reminder in my calendar to watch this again in about three months, just to keep myself on my toes. I've only had an electric shock once, and it was when I was very young (single digit years), I do not want that experience again. I still remember how it felt, not pleasant is an understatement.

As a Hybrid Automotive Tech, I absolutely 150% agree with this video. Every class you go to starts with “Not only CAN you get shocked very easily, you can DIE very easily”. 300+ volts of DC voltage from a traction battery literally designed to flow AMPS of current to electric motors should not be messed with by ANYONE but a licensed person with the proper equipment and know-how to safely disarm and disconnect traction batteries. Check your gloves. Check your self. Check your environment. And for the love of god, do not do it alone.

I've been very lucky and only had a few minor shocks, often from the 400VDC cap on switchmode PSUs. I once replaced several secondary-side caps on a SMPSU and only realised afterwards it had been switched on the whole time!

As a mum of an electrician who used to work daily with 25kV, I've heard too many tragedies of people who never made it through their shift. A common theme is inexperienced or overconfident workers or those working for less safety-conscious subcontractors. Never go ahead with a job that you aren't happy with, even if you're worried about looking like a coward or are threatened by 'superiors'. Going home to your family at the end of the day has to be the only priority. Thank you Clive for the important reminders of the dangers of working in small spaces and fault finding. Coincidentally those are the exact conditions my kid now works in, in the food industry! I will try not to worry.

The muscle grip issue is caused by what is actually a simple mechanism once you understand it. Muscle fibres can be roughly separated into two types = fast twitch (good for anerobic) and slow twitch (stamina). Weight for weight slow twitch is about 75% as strong as fast. However slow twitch is 90% of most muscles in anyone but sprinters. The body adapts to get maximum stamina by only using25% to 33% of slow twitch at any time and rotating through fibres so as to let them recover between work loads. So if you get a serious belt the electricity will fire all of the fast and slow twitch making someone just over 3 times stronger than normal.