The unofficial guide to electrocution (and how to avoid it)
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- เผยแพร่เมื่อ 22 พ.ย. 2021
- Super fast summary:-
Wet areas or ones with a lot of exposed metal pose the highest shock risk.
Confined areas or reaching into equipment pose a higher risk of fatality by trapping you during an electrical contact.
Treat everything as live even when seemingly isolated/disconnected due to the risk of backfeeds from other circuits.
Ordinary work gloves can reduce the risk of a serious shock greatly.
Safe electrical training can not be replaced with 1-5 day slideshow classes.
One thing I didn't mention in the video is the horrific way most fatal shocks occur. Workers making contact with live connections while in confined spaces or getting trapped reaching into equipment often die of oxygen starvation, as their ability to breathe and the heart's ability to pump blood is prevented by the flow of current through their body. Even when they black out they are often still passing current, and if not discovered quickly will not survive.
Gloves. If you touch an electrical connection with your bare hands, the only insulation between them and a VERY conductive interior is a layer of dead skin cells on the surface. They do not have a voltage rating and in the event of contact the skin's resistance rapidly breaks down. In the event of muscle contraction a larger area of skin makes contact and high current will flow.
While there are specifically rated live-work gloves, for less critical scenarios where you are not deliberately going to be handling live metal, a set of common work gloves adds a valuable extra layer of insulation to your hands. At the very least they can reduce the shock current of an accidental contact. The insulation of gloves is greatly reduced if they are wet.
CPR (Cardiopulmonary Resuscitation). This is a very volatile area, since every country has its own standards and there is a lot of folklore from the past.
The primary purpose of CPR (chest compressions) is to keep blood flowing around the body to prevent brain death. The theory that providing CPR to someone with a beating heart is dangerous has been disproven. Instead of wasting time trying to find a pulse, it is now considered a good option to immediately start chest compressions on an unconscious shock victim to get the existing oxygenated blood flowing to the brain. The act of compressing the chest can also cause airflow in the lungs, although the "breath of life" (mouth to mouth resuscitation) is useful if there is more than one person present.
In the event of the heart being in a state of fibrillation it is essential that it is resynced by an external defibrillator. Every second counts, as the chance of heart resync drops rapidly with time. Even when the paramedics arrive, continue doing chest compressions until told to stop.
Here's real video footage of CPR and a defibrillator being used on the victim of a pool electrocution. The fact the unit delivered a shock pulse indicates that it detected the heart was in a state of fibrillation, but still recoverable. The shock did resynchronise his heart.
NEVER work on anything electrical while standing in water, as a shock will involve massive current.
• Cops Use CPR To Save M...
Here are some video examples of shocks, noting that I will NOT be posting excessively graphic ones, and definitely not overhead line contacts.
Worker at top left corner makes contact with conductors of a live cable he is holding. Because the current is hand to hand, he manages to drop and gets lucky when the cable follows him down, but seems to short out as he hits the floor. Note how his arms have gone up to his chest and are so rigid that his left arm barely moves when it lands on the desk.
• ✔ DON'T PLAY WITH ELEC...
Example of contact with grounded metalwork while working on live circuitry. Legs in contact with bare metal, gripping on with one hand and coming into contact with an electrical connection with the other, made worse by his head contacting the metal ductwork too. I don't know what the outcome of this was. The fact he fell clear increases the chance of survival. This is a grim video.
• Repairman electrocuted...
Expect the unexpected. Guy being shocked by roller shutter that becomes live is pulled clear with a scarf.
• Quick thinking | Man s...
This video shows a guy getting a shock from the electrical trigger on a pressure washer (!!!).
It shows how a shock can affect part of your body, but still leave you able to do something about it. He survived.
• Lucky 'Stiff' Saves Hi...
This shows a horribly common shock scenario in the entertainment industry, sometimes caused by old or faulty tube/valve amplifiers. It results in a voltage difference between the strings of a guitar and a microphone. Note the loud squealing feedback noise when the guitar player on the left of the stage reaches up and grabs the microphone before collapsing.
• Member of Hot Hot Heat... - วิทยาศาสตร์และเทคโนโลยี
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.
A colleague of mine spent seven years apprenticing to be a painter and decorator. I used to pull his leg and say that the youngsters today are much cleverer and they could do that same course in two years😉 (I could run very fast in those days to make my escape after making such comments). In reality, my friend Jim was a highly skilled tradesman whose finished works were thing to behold.
After a really good apprenticeship, training with the best in the industry, the rest of your career needs to be spent learning every day. Being of the mindset that you still have much to learn is a great ingredient in some of the best technicians and tradespeople.
For our economy to thrive, we need to invest much more in peoples training. Some European countries will pay for peoples degrees if it is in certain spheres such as science, technology etc (Germany for example). We need to do the same to encourage companies to train to a high standard rather than get people out on the road earning money too quickly
Sadly, as a former apprentice supervisor and FE college lecturer, I've seen repeated reduction in the theory taught, less time allocated for 'on the job' training and shortened duration of the apprenticeship period. You only need to look at the content of college textbooks over the years to see the significant downskilling of technical education in this country.
@@michaelwilliams4086 Any kind of high standard training in the US is out of the question. If the standards were high, everyone wouldn't pass. If everyone doesn't pass you are discriminating against those who failed.
It is a load of crap but that's where we are right now.
I did my apprenticeship in the 90's (UK) was 3 years of college and was finally signed off by the teacher.
My current apprentice (here in Aus) did 1 day a week over 2 years (about 20 weeks a year) before they signed him off, ultimately it will be be putting my name to paper to say he is competent.
Doesn't seem right tbh.
Yeah well said Clive! What was missing in the video in my opinion is that there are few electricutions because there are rules and norms that have to be taught. E. g. try not to work on live systems if possible and make sure they are not live, stay that way and are grounded. Also it has to be made sure no one get's where there are live wires. This needs education and a deeper understanding for consequences.
Just this weekend I found out that in my apartment someone had installed a wall socket where this was not possible - by connecting neutral to PE wire... I had to remove the wall plug because I could not bear thinking about the possible consequence to have 240V on a PE contact which is easyly touchable here in Germany.
I found this to be much more helpful than any of my employer's safety training sessions.
This was deliberately down to earth and aimed at the reality that technical workers experience.
are they like my employers safety training where you sit there for 7 hrs to get a card that says you sat there for 7 hrs?
@@jsnsk101 That's quite like Corgi Gas training. I went from a career as an electronics engineer to a 'qualified' gas man in 5 days - 4 days training plus one for the exam. Sit here, listen and take notes and then on Friday morning do this 'exam' of multiple choice answers. If you got less than the pass mark you were given your answer paper back with the ones you got wrong marked in red, then you just did the test over and over again until you passed. That might take as long as - er - 2pm, after which you can go out into the big wide world and work on people's gas appliances.
@@jsnsk101 I once got a radiation protection supervisor certificate for a "course" that didn't have a test at the end. Not even a multiple choice one of the type with questions like, "You find a radioactive source. Should you (a) eat it or (b) not eat it?
Seriously. I've shared this with all my techs - such an excellent summary and review.
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'll actually plan on bookmarking the link. There is way too much misinformation about electrocution online. This is a great summary of what electrocution actually looks like and how to realistically look at the risks involved. It obviously doesn't cover everything there is to know, but it goes into surprising detail.
I’m absolutely positive this video already has or most certainly will save lives of technicians who watched this.
Which is absolutely its intended purpose. Stuff that none of the modern electrical courses even touches.
I worked 40 years as maintenance in a factory. "Expect the unexpected " is the best advice I've ever heard.
I take the same advice with driving too,and when on my motorbike !
And assume NOTHING !!
I also learned to "never assume"
A Chief Engineer threw that line at me quite a few years back…
I had nothing to come back with and it was then I realised that arguing with the Chief Engineer was not always a good idea.
Needless to say I have used the phrase quite a lot since then.
But if you expect it then it's not unexpected, so you need to look even deeper! :)
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. 👍
Sorry to hear about your brother. I wonder if the miswiring of the plug was the cause of the accident.
I'm sure that was a hard memory to dig up, but I appreciate you sharing the story. Stories like that and Clive's explanation are welcome reminders to many many people to be careful and pay attention to what they are doing.
Sorry to hear that. I had a friend who was electrocuted to death. I wasn’t there but they apparently stood on a live wire laying on the street while visiting Thailand. I still work with electricity. If anything, it’s a sobering reminder to me of the danger.
You only fear the unknown. It’s great to learn about the dangers and how you minimise / eliminate that risk to yourself.
Also Health & Safety law is very powerful and you can refuse to work if you feel unsafe for any reason not just for faulty electrics. If a superior tells you the equipment is safe, you can also insist that they touch it to prove it is safe to you and if they hesitate or refuse to touch it themselves, I would refuse to go near it.
Most of all if you respect electricity, don’t ever be complacent & take every precaution then you won’t have anything to fear.
The most memorable electric shock I ever received coincidentally was also in Thailand. I think they just have a very different safety culture.
I reached under the desk at the place where I was staying and felt a distinct but fortunately not life threatening shock. Apparently, there used to be an outlet under the desk, and somebody had moved it a few inches by splicing wires without wire nuts, electrical tape, or connectors of any type. Just bare hot wires sticking out of the wall at about 2 feet above the floor. Also, as I discovered, Thailand doesn't routinely install GFCI whole house protection either.
This was in a dark corner underneath a wooden table. Definitely a case of "the unexpected".
@@Stuntman707 As a former telecommunications installation technician, the most dangerous situations I've encountered were because somebody in charge did not supply proper safety equipment. Not having sufficient air blowers and gas-sensing monitors when a bunch of us were working in 4 or 5 manholes at once was a real problem; I got enough of a dose of whatever gas was down in that hole to make me feel like crap for days afterwards. Rickety 12 foot wooden ladders was another situation where I refused to work and went home for the day. And there was also a day when I and a coworker were installing conduit in an electrical room in a school and hit a fire sprinkler head with a piece of pipe, causing not a full water spray but a significant spurting leak. I don't quite know how we survived that one. ....
A soberly delivered video that might well save lives!
1. My sister's first husband trained in TV repair, and told me about the essential ingredient of keeping one hand behind your back - something that I do to this day even when opening a domestic distribution board cover, to the bemusement of the uneducated.
2. Back in the mid-80s, a salty older technician at the factory told us that the Electricity Board suffers more deaths than the Gas Board.
3. The electrician who did a recent inspection on my fixed wiring knew of your channel, so went up in my estimation.
4. One of the shortcomings of my current distribution board is lack of the latest circuit safety on my lighting circuits. Doh, says I, when I realise that changing a light bulb normally involves using two hands! Hmmm, where's my gloves?!
"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 remember from training that the safety requirements are much higher in electrically conductive confined spaces.
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!
Hot damn. I'm never looking at lifts the same way again.
Sounds like an arc flash. Would probably be a good idea to wear an arc flash jacket and visor as a precaution.
Wow, I wasn't to see pictures
I was working on a theatre show a while back, when one phase just dropped out.
Theatre was part of a college, so we spent ages tracing the circuits through panels in different parts of the larger building, and eventually found a 3x100a fuse panel with apparent burn marks, which we powered down and opened.
Found 2 100a fuses, and a carefully drilled teaspoon bolted into the third phase, catastrophically melted and having dripped molten spoon everywhere.
Looked liked it had sparked a fair bit, assumedly when there were just two broken ends of the spoon barely touching
@@tomaszwota1465 it's not just lifts, the huge levels of current in a dead short is the basis of fuse/breaker theory. However in this instance, correct sizing and selectivity should realistically have made the fuse to the lift blow first, so something isn't as it should have been and I'm not talking about the lead flashing! Prospective short circuit current at the origin can be in excess of 12,000A subject to proximity of substation 😳
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.
3. lock off the fusebox or switch
It's rare that I'd touch any mains power, but I did get some training on "lock-out, tag-out" practices. This would include locking a fuse or breaker panel where you had de-energized the circuit you were working on. Other folks could see your lock and come talk to you if they had any questions. Seems like a great idea!
this was first lesson at electricians school.
Remove fuses and take the fuse holders with you.
Tag the fusebox
Lock the fusebox (if possible)
They showed several videos of people dying on site (mostly CCTV footage and investigation results) and asked anyone that didn't understand the significance to leave the school and find another occupation.
Although I studied electronics and didn't deal with construction, that lesson was mandatory and is burned into my memory.
Most of my zaps have been caps in SMPSs and RF burns on radio kit.
This incident was probably the best part of 50 years ago, so maybe they didn't have the lockable boxes in those days.
"So he decked the foreman and walked off site."
❤️❤️❤️
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.
The way some tree trimmers work around live cables is scary.
They are trying very hard to eliminate the practice (!) of plugging a generator into the circuit panel during outages. All it takes in one and the guy at the pole has a bad day.
I lost a 13y old nephew nearly 20y ago by 220V. It was an household accident, he did not do anything intentionally wrong. And I was the nerd uncle, who survived so many dangerous experiments with live lines when I was in his age.
I had lots of luck and (as men are not after smooth skin) enough ultra dry cornea to get just enough pain to be more careful next time. After some „strokes“ from motor ignition systems I knew that kV‘s are to be avoided, so I never let a CRT spark on me, but 220V live lines reached me from time to time.
There the story told by my (in between passed away) parents, that at the age of 1y, I got hold of a lamp without the bulb, put the plug into the wall outlet, put my thumb into the bulb socket and switch on. My first contact to electricity, with did not end till today. I‘m now an software guy, but still designing/building circuits or repairing/modifying 220/400V systems at home.
@@fromgermany271 Although it was 20 years ago I feel it is appropriate to offer my sincere condolences on the terrible loss of you nephew. I nearly died at age 10 in a household accident with 240V, so your nephews death particularly resonates sadly. Sounds like you and I have been very lucky to survive our contacts with electricity.
May I offer my sincerest condolences to you, his parents and family on the death of your cousin. A horrendous tragedy that I so wish had been avoided.
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.
Yes, always test everything. Worked on a heating system that was switched off grid but still a part was life, that was powered by the fire suppressing system over a second power rail. If I would not have tested on multiple points, that would have hurt a lot.
25+ years, but this is correct, cutting corners to work faster, means cutting down on safety. (and no one will thank you for that)
I can also add, never ever trust another person, test for voltage, disconnect, test again and test it yourself.
Last time I trusted another person, he accidentally disconnected the wrong cable, so when I opened the socket, I got some sparks around my screwdriver.
This time, Extra isolated screwdriver, gloves, and isolated shoes, and even a RCD, but the fuse blew instead. (Never got any voltage, one thing wrong, many other correct)
I have the dubious pleasure to also work on "Electrophoresis power supplies", these are DC power supplies than can deliver up to DC 3kV and 100mA.
There are all sorts of safety interlocks, but when you are trying to fault find you end up bridging a number of these out.
90% of my time is spent think about how to put these things into a known (but unsafe) condition so that I can take measurements (my work bench has body protected RCDs which I insisted on when I got the job). Even then I need to be clear headed, I talk myself through what I am going to do, what the risks are near me if it should suddenly burst into life (ie you have just put a probe on a dry joint ).
I had done this one day when an external electrical contractor started flicking breakers off then on again as he tried to find the one he was wanting. This meant some of my "known" conditions disappeared and it all came live. Fortunately I pulled my hands away when the power went out.
My reaction was to go thump the idiot who was doing work without notifying anyone, he certainly got sworn at VERY loudly, got told where I would stick his pliers if he did it again, and gave his ladder a bloody great kick pointing out that he could have killed me.
@@keithwhitehead4897 when I know I'm not working alone, I use breaker locks. the bigger main switches have already holes for locks.
Tom Collins, indeed ! As you say about "trying to do something faster or the "easy way" . . . there's an expression about "gambling addiction" that says "when you lose . . . it's bad . . . when you win . . . it's worse." Every time we "get away" with doing something 'the easy way" its apt to reinforce BAD habits ! :-o
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.
No such thing as "needless caution" around such voltages, Mr O'Stuff.
"Needless" caution is preferable to needless death. I wouldn't like to work with anyone who thinks that I am too cautious. It indicates that they are less cautious and could possibly put me in danger.
And congratulations to your boss for not being an idiot.
In the world of radio engineering, tubes are becoming quite rare. I started with full 100kW FM's in my career 20 years ago, and at the time all of them were tube with 7-10KV plate potentials. I often worked alone at night, but there were protocols for such work. We had a grounding lead we would bridge out the HT with. Also, all of our transmitters had shorting switches that did work, but I always checked with the shorting stick. With modern LDMOS devices, HV is quickly becoming a thing of the past. I recently worked on an install of two 60KW UHF transmitters...all solid state. Primary voltage was 208 three phase IIRC.
Working around hot AM equipment is another specialty that not many folks understand. If I was working on the tower, we would bridge out the spark gap of the tower with a jumper cable to ensure the transmitter couldn't come on and burn someone. Although I have jumped onto hot towers before, and in some cases didn't even notice.
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.
Yeah..this always makes me wonder about hybrids in junkyards...
Always stay safe around that equipment, but I can tell you that the 260V hybrid batteries are a lot more safe to get shocked by than a mains outlet due to them being DC. 600-800V packs are a different story, still a very good chance of surviving but the burns will be very bad.
DC is safer by a factor of about 10 because it doesnt lock up the muscles as easily as AC does.
@@forbiddenera The batteries have clear labels on them and are self contained (there is no dangerous voltages anywhere except inside the battery pack when the car is off).
I was talking to a guy in the pub last night who works in an electric car factory. Seriously hoping electric car owners don't start tinkering at home. It's not 12 volts. More like 420 at hundreds of amps. It wouldn't have a survival option.
@@drkastenbrot The 600-800 volt ones would be as dangerous as the live rail on the train lines
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.
The times we live in now. You can come to office in shorts and it’s called culture, not disrespect.
@@arthurmorgan8966 I know what you mean, and while I prefer to dress for comfort there are limits. For me disrespect is someone who is glued to their phone screen and not performing the task for which they are being paid. My wife and I have reduced the size our businesses because there too many people not willing
to put in a fair effort for fair remuneration.
@@andrew_koala2974 Interesting, most, if not all people I know who have survived a life threatening shock remember precisely where they were and what they were doing. The brain's way of saying "Hey mate, don't do that again!"
The biggest shock here was gladly putting that magnificent beard to those dulcet tones i have got used to. I used to drive trains for BR and if you had to change a shoe fuse, you had to isolate the train from the dc 750 volts. Yes we learnt how to be safe, previously when i did city & guilds one year, we got officially trained to wire up a three pin plug. You got a 20 lecture with demonstration, one practice run and one attempt to get it right. If you failed this, you failed the whole thing. On the railway and working on dc we were told if you see someone on the juice rail, we have two mins to get that short circuit bar down, which shorted out the juice rail through the running rail, threw all signals back to red within 1/4 mile and then you removed them as it only took two minutes to starve the brain of oxygen thus causing brain damage and or then death.Later on i also worked with the overhead electrics, 25,000 volts ac. We were told it wasn't the volts that kill you, its the amps. Even safer now that you get screwdrivers that show proof of power and cheap safe monitoring, my latest one cost less than a fiver. Hold next to cable and it shows if live or not. Great piece of work from you, yet again, but as i said, even better to put a face to that voice.👍👍👍
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.
Was thinking that doesn't seem like a properly functioning energiser. Agricultural electric fences should never be capable of delivering a dangerous shock, just a painful one. No farmer wants a field full of dead livestock for a start!
@@Croz89 probably didn’t use inverters to run the voltage far enough and had to compensate with higher amperage; this a stronger than tolerant shock on much larger wire.
Phobia my pink ass, that's hard-earned wisdom! Do NOT "get over it", keep treating anything that might be electrified with the deepest respect.
The electric fences I touched as a kid seemed to send pulses, you could grab the wire at the right time to feel nothing or grab it and get a belt of power, I don't pretend to know how they worked but that what me and my sisters found out about them.
@@BitchyBoxxy Or had the pulse width *way* too long with an oversized capacitor. A typical 3-5kV electric fence should only have a very small duty cycle to be safe.
Well done Clive I am Cathy's hubby name ron and a retired sparky.
It is about time someone told the truth about electric shock.
If you save just one life it will have been worth it.
My wife used to work with me.
Due to our health we are both now retired.
Electricity is dangerous in the wrong hands.
And we have had to put right work carried out by Muppets that had no idea what they were doing.
All the best from us both for the festive season.
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.
Much the same as I was taught. I spent 20 odd years working on some pretty high power radar, back in the days of when things glowed pink and purple even in daylight. As the saying went - no rings, no watchstraps, keep one hand in your pocket and don't F about.
If you assume everything is gonna kill you survive lol
@@thearmouredpenguin7148 damn. Definitely wouldn't want something to arc to your watch or something...
"Treat everything as live even when seemingly isolated/disconnected due to the risk of backfeeds from other circuits."
This saved my bacon three weeks ago, even though I was "positive" the circuit was isolated.
I worked in the service and repair department of a large NDT and Inspection company for a lot of years.
Shocks on mains powered equipment did happen as most equipment had to be energised and open to ascertain the point in a cycle that the fault would occur.
I, however, specialised with industrial X-ray machines. The X-ray tubes on some were connected to large high voltage generators via thick high voltage cables. The voltages of the common X-ray machines were 160KV, there were some 200KV machines, and one 420KV machine. They had "fail-safe" earth bars that when powered down would short out the high voltage capacitors, the charge build up in the cable, and the X-ray tube's charge.
Sometimes failure of the machine would, through fatigue, fail to fully return to the shorted position. Dry ground and latex gloves become conductors at these levels and a few of the discharges were like lightning as it connects to my hands.
The worst shock at work which had lots of test on myself was due to lightning hitting the gable end of the building. It travelled down the wall which I was next to whilst using a PC to fill out a service report. I just remember 3 bright flashes engulf my arm and a gained composure 3 metres away on the ground. My right arm and leg where in agony as I hobbled around the workshop shouting expletives.
A guy on the otherside of the dividing wall was also thrown back and ended up with a broken arm because of the force of his muscles contracting.
I was lucky, the hospital ran quite a few tests on my heart, my hand that was using the computer mouse had faint char marks and smell as well as my foot.
My muscles had an ache that was akin to slight muscle tearing, the hospital said it was due to the nerves being damaged, so I have sciatica and the same feeling in my arm but it just comes and goes now.
I don't think I'm immune to electrocution but I've been very fortunate to have survived some quite large electric shocks.
Incidentally, my PC and quite a lot of the other PCs in the building were damaged, the fire alarm, burglar alarm, and some mains circuits were also damaged. It had also fed back to the main building to the server but the IO switches were the only things damaged.
The modern training approach seems to tell people not to work live at all. But in reality, to troubleshoot machines you often HAVE to have the power on.
I do agree though that if the item that is faulty can be tested without energising with mains then not energise it.
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!
When working on anything line powered I always try to make a point of having the plug visible on the bench to prevent such things.
Try it again with a fully charged 400 volt bank of those (20 of them or more)
Always check voltages AC and DC before working on anything.
I work for an electrolytic capacitor manufacturer. We test them AT and ABOVE RATED VOLTAGE. I do my best to treat any cap as if it were charged. I try to get that point across to anyone that I can. Yes, I have been intimately acquainted with a couple charged capacitors.
The human body is less susceptible to harm from DC sources - AC is the killer. Back in the days as a young engineer, I occasionally got clipped by 450v DC supply rails in tube amps and brushed it off - any contact with the 240v AC mains supply was a lot more unpleasant.
I work on electrical equipment at my business. I try to be cognizant of the dangers, and I really appreciate the reminder. One of my suppliers died when removing some equipment for replacement. One life saved is completely worth the reminder!
One Moment Please ........ A huge round of applause for one of the best videos on the subject I have ever seen! I'm a surgeon who has picked up many cases covered by this gentleman and his advice is pure gold - A huge thank you Clive, keep up your immensely entertaining and informative channel - genuine thanks.
When I was a wee little lad (yes, I've actually been "little") I was alone with my dad at the summer house. I was out playing in the garden while he went inside to make some lunch.
My mother had several times complained about small shocks at the stove and my dad had tried to find the cause but not called an electrician (note the "small" above).
Well this very warm and thus sweaty day he found it.
With one damp hand on the sink and a sweaty palm of the stove he got stuck.
He couldn't recall how long it actually took and I (luckily being perhaps 5 years) didn't note a thing but it was far from pleasant for him.
Many years later we tore down that house since they had decided to build a more proper house and we found the base cause. In the roof there was a hidden junction and in that one of the phases to the stove had been swapped with neutral or earth (don't remember which).
And thanks for a well done and informative video.
One thing about first aid - check for breath before CPR, if you can't note breathing (listen, feel, look) start CPR.
The reason that pulse control is skipped is rather easy: No pulse = breathing stops + no breathing=pulse stops. They are linked and it is hard to judge pulse, especially with adrenaline in your body likely going nuts.
And if CPR is needed only one thing is sure, the person will die if it's not administered!
It's really had to test for either pulse or breath in the heat of the moment. Unless you are trained for it, it's unlikely that the average person can detect a weak pulse or breathing. Best thing is to start CPR right away, it can never hurt. These are the new rules since they changed them not so many years ago. Lives were lost while people were fumbling to check for pulse and breath, even trained ones. Every second matters, literally.
@@ligius3 Now we are told to do chest compressions to the beat of Stayin' Alive. If I get confused and do them to the neat of Another One Bites the Dust instead will I kill them?
Excellent points Clive! I had seven weeks of training to be a lineman back in the 70's and in the last week we had to do a "pole-top" rescue. A 150 pound dummy was hanging in his belt 30 feet up on a pole and we had to get him safely down. First clear the contact if necessary, and once at the man start CPR right away, then using a hand-line lower him to the ground and start CPR. During my years of service one man was killed durning storm restoration, he did not ground both side of his work and wasn't using his rubber gloves and a farmer miles away started his generator and the disconnect switch failed and allow a back feed. I was surprised how many of my coworkers did not understand that a grounded neutral was a "current carrying conductor", and one guy almost opened a neutral up before I stopped him, the neutral carries the unbalance in the system and unless it is perfectly balanced there will be current flowing in it. I loved storm work and seen some incredible stuff! Transformers blown right off a pole, and I once had to climb a pole in -70f windchills and splice wire that snapped in the cold. The oil was so thick the bucket truck it would not function. Good stuff!
Yeah, bucket trucks can run really slow in winter until they warm up.
Windchill only relates to warm humans, not hydraulic oil !
Once in Phoenix AZ a pole transformer exploded in a monsoon thunderstorm so violently that it spewed molten copper and transformer all over my next-door neighbor's yard. The transformer oil stank for days even after the cleanup crew removed and replaced all the soil in his yard. Lightning had hit a line a couple miles away and a very slightly corroded connection on that transformer took all that energy and turned it into heat, apparently. Nothing else was damaged. Weird stuff.
Lightning is incredibly powerful! Some of those older transformers had PCB's in the oil as a fire retardant so dangerous stuff. I seen a huge white pine tree get hit with lightning and it blew chunks for 50 yards and it followed the root system out and laid the soil back like it was plowed! Nothing to fool with, you hear thunder get inside.
My brother-in-law got a "friend" to wire in a backup generator without a disconnect, but my electrician brother heard about it and made time to go install one. Amazing how careless some people can be about other peoples' lives.
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.
You want to avoid that keeping on your toes sensation, Justin.
Stay safe!
You HOPE you haven't been careless? How about just not being careless? It's not hard.
@@looksirdroids9134 You sound like a Karen that's never been on a construction site. In the real world shit happens. You wake up probably have a fever and are light-headed but that newbuild you've been working on has walls being installed tomorrow and electrical has to be done today so there's no sickday and you go and you hope and you do your best. It's a regular occurance for tradesmen.
Ah yes, the classic “utensil in an electric socket”. That’s one childhood experience you will never forget.
I exploded a key by sticking it in where a switch was. I was lucky, I didn't get shocked. I was really young. @@c0d3r1f1c
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.
Thanks for this enlightening explanation!
Ah yes - I remember this from my biochemistry days.... thankfully there weren't too many of those because... that's about all I understood of it.
Confined space work (I work in the food industry as an engineer) is always on the buddy system. Its always a minimum 3 man operation. There is the worker in the space performing the work, he has a watcher in the space not doing the work who is prepared to extricate and then another watcher who is external to the space who has comms at the ready should an emergency arise. Typically this person also has a fire extinguisher (if fire is possible) and a tether to the worker that is routed out external. Confined space work is also reviewed in advance of the start of work and the area accessed for hazards and a lockout team is assigned to assure all energies are removed. Its pretty legit in the food industry in the US and Canada.
Also, for me specifically. I NEVER work two handed when probing in a panel. I use a clip for my ground and then probe one handed. If I cannot and the terminals are close by, I hold the probes like chopsticks and probe with both in one hand. That way if there is a slip, its a shock across the hand and not across the chest. Hand to hand across the chest is the real killer. Those rubberized fabric gloves are also extremely handy and aa great invention.
Ah yes, I've seen some engineers filling potholes using that same strategy, safety first
@@FerdinandFake how are potholes confined space work? Am I missing something?
@@cheater00 maybe theyre being extra careful, but its always one guy working and a bunch of people watching
Maybe not the right video for lowbrow jokes but years of working on live equipment made me jaded. Or maybe the fact that we have RCDs pretty much everywhere here, makes people lazy.
Correct, Clive
As a Paramedic, I'm most interest post electrocution what the heart is currently doing. Underlying heart conditions and then add into the mix Line voltage and possibly a current across the hearts pacemaker cells isn't a pleasant mix. The last proper electrocution was a chap who'd been working on I presume a 3 phase garage lift and got a shock. He was in a SVT ryhtm which later degraded into VT en route to hospital. A shock from our defibrillator brought it back into a stable rhytm.
Another aspect I've seen is arc flash burns. Or even mains voltage causing localised burns on hands etc.
Fortunately it's all very rare and all the incidents I've been to are industrial settings which goes to show how safe in general domestic settings are now a days.
I used to work as a service technician in a semiconductor firm so it gives me an understanding into industrial processes that often I feel is overlooked in general paramedic training.
Arc flash is bad medicine.
Nothing good comes from super heated plasma balls roaming around at eye ball level.
This video is sad.
Either the repairman got in a hurry and got careless or he had never been trained on the danger, had gotten by with it before and his luck ran out.
Either way it was a horrible ay to go.
th-cam.com/video/hfnEuRA7-vo/w-d-xo.html
In my experience, you do feel AC contact even when you are insulated from ambient ground, as a deeply unpleasant 50Hz jitter in the extremity in contact with the phase. Basically the single-body capacitance of the body being charged and discharged.
Thanks for promoting this Clive. When I was much younger, my old Gran needed her kitchen under cupboard mini fluorescent tube changing. I was working blind and I touched the 2 mains contacts with my left and right hands. Needlessly to say and luckily I got launched backwards and found myself on the floor and my heart was going crazy. I don’t think I’d survive that now being slightly older! Huge lesson.
I served a 4 year toolmaking apprenticeship 30 years ago and safety was drummed into me. The people I work with today seem to be more focused on completing course work and don't fully understand the dangers of industrial work. I think they assume health and safety has covered that for them.
Another great and informative video, Clive.
Health and Safety is written in blood pain and the occasional closed coffin funeral. PS I will learn to spell one day.
Honestly I find it hard to blame young folks still in or fresh out of schooling when the industry has absolutely no interest in comprehensive training. They've cut it down to the absolutely least training they can get away with. They know kids are desperate for jobs to pay off their student debt and betting they won't know the difference.
There's a lot of folks too eager and not willing enough to put in the training, but in the end its the workplace's job to give the workers the tools they need. Schooling too. A lot of people are paying ridiculous money for schooling that just doesn't teach them nearly enough of the practical skills they need, especially in trades.
To put it more succinctly: no electrician should be learning basic safety when they're already on the job. Not even an apprentice or student working with actual equipment. We wouldn't let doctors learn the basics on the job, afterall.
When I was young, I was trying out a stereo electric bass in a music store. I just had to try it through two amps - big mistake. With the bass connected to the amp in one hand, the moment I picked up the input cable connected to the other amp I found I was knocked to the floor and couldn't let go of either. I did manage to make a sound which got the attention of the proprietor who jumped over the counter and pulled the plug on the 2nd amp thereby breaking the connection. Paramedics came and gave me a nice ride to the hospital in an ambulance. That could have ended very badly.
Some of the old tube amps had the input referenced to the mains. There have been a lot of accidents involving them, including fatalities.
I've been in the sound business all my life. I can't tell you how many tubed guitar amplifiers vs grounded microphone issues I've witnessed.
i've been a bassist/guitarist my entire life and never knew there was any risk of a shock through amp cables...... but then again i still have no real idea of how any of my kit works :)
@@Broken_Yugo Also a great band name!
Reminds me of how Suzy Quatro died in Midsomer Murders.
I watched a fellow worker get electrocuted years ago, I'll never forget his screams. He disconnected a large heating element cable that had missing insulators. Dropped to his knees unable to drop the cables. He was saved by someone close by that kicked the cable out of his hand. Its always stayed with me.
Very helpful advice. I'd expand slightly upon the chest compressions. I was taught the rate is 100 per minute, or the beat of the song "Staying Alive".
One thing i always need to reiterate to my co workers is that neutral connections can be just as deadly as the live ones depending on the way in which your working on them. Damage to property and person can happen especially when working on the main neutral connection in a building or where a neutral is shared and carrying current.
I received one of my worst shocks from a shared neutral while on a ladder with my head stuck in the ceiling cavity. I learned a valuable lesson that day and have not repeated that mistake.
The irony with this comment is that when I did electrical engineering the tutor went out of his way to show that touching the neutral wont hurt you. Probably not a good lesson to be teaching.
Fran Blanche once showed how she added grounded outlets in her shop by jumpering ground to neutral at the outlets. The irony is that she doesn't want to move to a cheaper place because she's worried about being murdered, but those ground connections she made means the neutral wire is one loose connection away from becoming a potential murderer right in her own shop.
I try to call them the common rail, vs neutral, just to try to reduce that ill-formed assumption.
I had a next door neighbour who was doing some tinkering in his 60's property (UK) and changing the kitchen light fitting, which he'd switched off at the wall, but when he started to untwist the neutral it started sparking - in those days all the neutrals tended to return via a common light fitting and that was the one, and another light was on and feeding return current via the very wire he was untwisting - oops. That was the early 70's!
A common mistake I know of in home DIY, is when people reverse the Live and Neutral.
Plenty of cases exist where there is only a switch on the live end, while part of the object has an exposed neutral connection. For example, if a kid shoves a knife in an old toaster to get some bread out, but it is actually still live because of a swapped connection at the plug/socket.
Thanks for the clear explanation of the muscle contractions. I started having seizures years after a head injury. Now I have medications that work. My seizures caused violently hard muscle contractions. It was always the day afterwards that I had horrible muscle pain. Since I'm mentioning seizures: NEVER EVER PUT ANYTHING IN A PERSON MOUTH!!! Tongues cannot be swallowed, but putting something in a persons mouth can break teeth or get your own fingers bitten off. If they are standing, when the seizure ends you will need to catch them and keep them from falling hard.
I will be saving a copy of this video to show people helping me what not to do. Thanks
Everyday is a school day you can't learn enough about electrical safety, thank you Clive
When I was a kid, a friend of mine was running around his back yard and got a sticker in his foot...he hopped over to the window AC unit, put his hand on the bracing of the unit with one hand so he could lift up his foot to remove the sticker. Well, there was a puddle of water under the unit and he made a connection. He was stuck on there for a minute before his mother saw him and knocked him off with a broom. He survived, but his feet were burned and cracked severely and he couldn't really talk for about an hour.
That was close. It could either have been a faulty and ungrounded air conditioner, or it could have been a voltage external to the house's ground zone.
I've been shocked off of those old window units. Before the mid 60's , they weren't grounded.
Bloody hell! Good thinking of his mum
Ever since I switched from cigarettes to vaping, I gained interest in electrodynamics due to all the settings found on regulated vape devices such as variable voltage, temperature control range, custom curve wattage, the necessity for a solid understanding of Ohms law if using an unregulated device, and so forth.
I've watched a lot of content from people like styropyro, ElectroBOOM and many of the likes. This is by far one of the most well assembled, applicable and informative pieces of content surrounding this subject that I have seen so far. You've earned a subscriber.
Clive, I'm pretty sure you saved me from some serious trouble. I was working on some 240V equipment a while ago and failed to isolate part of the system by mistake. I worked for about a minute on live connections. But thanks to the advice you've given over the years, nothing happened. The layered safeties worked (chiefly: electrical environment awareness and expecting the unexpected, albeit delayed), and the only damage was to my ego when I realized the circuit was live. I thought I was being careful but clearly not. Thanks for condensing all this information into a single handy video; I'll make all my electrically-inclined friends watch it.
About a year or so ago, I got shocked while arc melting copper with a microwave oven transformer whose high voltage (about 1500-2500 volts, AC mind you) output was connected in series to two high voltage microwave capacitors. I had gotten too comfortable around high voltage (a mistake everyone working in the field needs to remember to never make) and I went to make sure the transformer wasn't overheating by touching the body of the transformer. Unfortunately, not only had I forgot to unplug it from the mains, but I was also holding one of the HV output leads with insulated pliers. Needless to say I got hit VERY hard as the high voltage actually broke down the insulation in the pliers and arced straight through me. When my arm muscles contracted and pulled my hands up to my chest the arc moved through the tip of the pliers to my chest instead of my hand as that was the shortest path, and that's where most of the damage occured. It all went across my chest and I could feel the 60Hz buzzing all across my body as I held on for a good four seconds before I got a rogue jolt and pulled back so far I pulled the transformer off the table and it unplugged itself. My grandmother was absolutely fuming when I woke her up and absolutely begged to go to the emergency room to make sure I was OK. By some miracle, my heart was OK and I do not have any heart problems after that incident somehow. I only came out with severe burns on my chest and hands (now permanent scars).
Remember kids, do NOT play with high voltage!
I still have the microwave transformer but now I have a breaker and two main switches in series and a kill switch in series with the mains and several warning indicators, and the transformer is completely enclosed. In addition, I have someone else on site when I'm using it just in case something goes wrong. I almost never use it now except as a Jacobs ladder or something every now and then , but now I am always INCREDIBLY careful around any voltages greater than 40 volts. I now ALWAYS do my best to implement the most precautions possible.
Shocked or electrocuted?
I'm under the impression that at very high voltages (in the 10's of KV range), the current essentially cooks your organs on its way to ground, killing you pretty much instantly.
@@theotherwalt Oops, edited lmfao
Holy shit!
@@Croz89 At extremely high power, it can essentially vaporise anything with water in it instantaneously. Enough current and voltage means enough energy available to do it. This is why ultracapacitors are so incredibly dangerous actually, they have the capability to store enough energy to basically blow a fully grown adult's insides (and probably outsides) into smithereens. Very gruesome.
The way that it works (as far as I'm aware, I could be incorrect so correct me if I'm wrong!!) is that the electricity actually is evaporating the water in your cells incredibly rapidly and thus tearing them apart and turning them into a dust and vapour. The speed at which this occurs is dependent on both voltage and current and the ability of the source to dump the energy in the shortest period of time.
Thank you Clive. You have definitely saved a life (or lives) with this one straightforward presentation.
Thank you, Clive. You may have saved a life, today.
I am like you Clive, a Technical Person, who has been playing with electricity since I was a child. I have had many minor shocks over the years. Worst one though was totally unexpected from an old metal pop-up toaster, which I went to shake out with both hands over the sink. I didn't notice that the plastic cover on the cord terminals underneath had come off, and one thumb went right on the live, whilst both hands were on the earthed body. My hands contracted, but after a few seconds I managed to force them open and threw the toaster on the floor. Gave me a big scare! My immediate reaction was to smash the evil toaster...
I really want to thank you for this Clive, as a self taught DIY'er this is vital, easily understandable information even if only to confirm what I've learned is valid. The worst shock I've had is from a mixer faucet due to a faulty multi-point water heater in a rented property, now I know it was my legs that launched me across the bathroom (not quick reflexes) but I'll never forget that 50Hz resonating through my entire body, still gives me the willies just thinking about it.
Oh yes, I had this as a child from the days before 13A plug safety standards enhanced with that plastic insulator on the supply pins. I'm not sure if this is true but because I touched both live and neutral with my thumb and 3rd finger, the feeling seemed to affect mostly my hand but I did get to hear/feel the low hum in my head. I was lucky. My dad flipped the switch before I came a real cropper.
@@EdgyNumber1 Me too, in the 1950's with the round pin plugs and no earth gate in the sockets. You coud poke your mum's metal knitting needle into any of the sockets and see if you could tell the difference!
@@EdgyNumber1 I remember when I was ... maybe seven... unscrewing the switch on my grandmother's table lamp. I wanted to know why one end of it was black and the other was white. I found out.
I think the following advice may make sense 1. Take a CPR, first responder or other type class offered in your area. If you come across someone who has had an accident, you will know how to respond. 2. take and pay attention in any classes offered on safety by your employer or labor union etc.
Why isn't first aid a mandatory course in school?
Thank you for this lesson. I've been "bitten" a few times, luckily never anything as serious as in the videos you have posted in the comment. In my country we have mandatory electrical safety courses you have to go through depending on your employment. Any technical jobs require you to take a 10 hour course (about a week long, a couple hours daily) of actual school. At the end of the course you are given an exam. It's no joke. And this isn't for an electrician job. This was when I started work as an operator of a production line in a brewery. My job did not involve opening any breaker panels or anything. This is a course that gives you a "clearance" level that allows you to plug in computers and other office equipment into wall outlets. Technically if you work in an OFFICE, the only electrical thing you are allowed to touch without taking this course is... things connected to the computer. NON-line voltage stuff. If you want to be allowed to turn on lights via a wall switch - you must have a safety lesson (about 45 minutes) from a "certified" person that has taken the basic 10 hour course I mentioned. If you want to plug that computer into the wall - then you gotta take the course. It may seem a little "over the top" and bureaucratic, but it actually makes perfect sense. I am VERY thankful to "The System" for making me go through that course because I feel like it has come in handy in my day to day life and hobbies, and not just "necessary for the job".
Again - thank you for this video and all of your content. Keep up the great work. Always eagerly awaiting your next video.
Thank you Clive. I am seventy three years old and still alive! I have had over three hundred odd electric shocks of all types. Many 240 volt from replacing GPO outlets and not disconnecting the supply to regulated colour TV EHT supplies. The worst I had was working on 500 watt transmitter tuning the penultimate output stage. It had a 15,000 volt DC supply with RF on the tank coil. I could only tune with the HV on and all the access gate switches bypassed. I ran the two out bottles for 15 minutes and then went through the tuning process according to the book! Very difficult to access the tuning bridge on the anodes and yes it bit me. laid me out for a couple of shaky minutes and BBQ fingers. It was 3 am in the morning and had to complete the job! After tuning and allowing the output tubes to settle down, I closed it up and left the transmitter to do it's work. I followed up with a visit to the hospital for repairs to my hand and fingers from the DC arc and the RF burns.
Thank you for your very interesting and educational programmes.
Kind regards,
Roger Bird (Australia)
Nothing controversial, good practical advice. The only additional tip I learned is to work with your non-dominant hand behind your back to reduce the risk of shock across the heart (not that anyone works on live equipment 😉).
I learned the same thing....posted above. I always probe single handed with a meter and when poking around, one hand is beyond my back.
It's doubly important, when working around multi-phase equipment.
You don't want to get across two phases.
Also, no rings on fingers, and watch removed from wrist. Along with one hand behind the back, that's how we adjusted the deflection yoke and magnets on computer displays in the 1970's. Often there was a few hundred volts on the PCB at the end of the CRT which was far too easy to touch accidentally. I'm still here, so it was clearly good advice.
@@GodmanchesterGoblin I got a metal wristwatch between positive and ground on a tractor with my hand jammed between the starter and bonnet panel. Still have the scar over twenty years later. 12v DC and a cartload of amps...
@@bobs12andahalf2 Nasty! It was also an issue in the early days of computers. Big power supplies could easily put out a hundred amps or more - enough to weld the contact securely so that the watch or ring heats up even more quickly... :( Car, truck or tractor batteries would be an even bigger risk of course.
Thank you for explaining that "getting a shock" is not the same as "getting electrocuted" - my pet peeve! I used to work on high power broadcast transmitters, and all of us who did that same work always knew to keep one hand in the pocket if you had to bypass the safety switches and work on an operating transmitter :)
And HF burns are worse than ordinary electric burns too, trust me - I did get a small spot burn from a small transmitter once and that was bad enough. Only 50W VHF, but it was enough. I was about to arrange the antenna and another dude tested the repeater at the same time.
my pet peeve too! I've had way to many convo's like this:
"I got electrocuted"
"uhh, no you didn't"
"how would you know?!"
"you're alive"
Thanks Clive. A timely reminder to a DIY'er with an electrical degree who thought he knew / remembered and now realises he doesn't. I wish I could recommend this 1000 times.
Great video sir. Before i finished technical highschool as an electrician we had one teacher telling us the same things and he even showed us some graphic videos but not all the students took him seriously. Safety should always be number 1 priority
A thing you mentioned a while back comes to mind. When you need to work on electrically isolated wires, never start your work by just grabbing on to them with your fingers but first touch them with the back of your hand. If you do get that once-in-a-million-times shock at least you won't be clamping the wire because, as you mentioned in this video, your hands will clench to a fist. Using gloves might be even better but for the people who can't or won't wear them it might still be helpful.
Exactly. When I was a newbie one of the old-timers told me even after verifying the circuit was dead, to always "knock" on the potentially energized bits with the back of your fingers before grasping them so you will pull away rather than grabbing and potentially locking on.
standard practice offshore, not just for wires, but heat and any other danger - you can still use your hand if the back is burned
I was taught this by an old school TV repair man. The other tip he gave me is never wear a watch with a metal strap or a metal bracelet at work.
Standard practice in the fire service when feeling your way round a building for that very reason.
Ditto.. As a 11kV Engineer putting people to work, I always touch conductor first to prove dead to operative(after using test equipment obviously). This is always back of hand...🤚🏻
Good, sound advice and informative chat Clive, thanks.
Top tip I got at college was to approach even a cubicle with suspicion. To touch-test the door handle, put one hand in your pocket, and with the back of the fingers of the free hand touch the object. If you take a "belt of electricity" your gripping motion will move your hand away and disconnect you from the contact. Granted this advise was given over 40 years ago and now people can carry handy pocket indicators for AC voltages and just poke them at stuff. (I had one that used to tell me I had an incoming call to my mobile phone even before the phone rang).
I wasn't alive forty years ago, but I was still taught that early on.
One pitfall of this test is that sometimes you can have so good of an insulation from the ground that you won't feel anything. Always make multiple tests to be sure.
But it takes a second and if you get shocked at least you'll know for sure you might have just avoided a serious accident.
Brilliant informative as always Clive, from a 20 year Self Employmed Sparkie, here in the UK. We were refurbishing an old 60's hospital, and 20 Fluoro/tube fittings were on a 'borrowed neutral' and I obviously thought they were dead as they all went out as I pulled the fuse. I went up my insulated steps and touched the connections and got the most horrendous belt. Luckily I was working in the right place!! Keep up the great work..Respect electricity and you should be ok
Back in 1984 I was electrocuted by 161kv power lines. These are the lines you see hung between those 100ft towers that carry a lot of power between cities and towns. In telling the story I have to admit to doing something stupid but I’ll do it anyway. I was 20 y/o at the time but a few years before this me and the neighbor hood kids would fly control line model airplanes in this field in front of our house. The power lines ran across this field and the lowest line was about 27ft above the ground. For those who don’t know control line planes are the ones you would stand in a field and hold a handle and there were 2 lines running from the handle to the plane and they control the elevator on the plane so you could make the plane go up or down while you rotated as the fly flew around you. These planes used basically kite string which wasn’t conductive so no real danger of electricity getting to you even if the plane hit the power line but we were quite a distance from the power lines anyway.
However, this particular day me and my brother were bored and decided to fly a model we had never flown and we really didn’t fly these planes anymore but thought we’d try it anyway. Now this model was bigger than the small plastic planes we flew in the past. This plane flew in a 90ft circle about 120mph and therefore we needed to use stainless steel lines (conductive) from the handle to the plane. We laid the plane and lines out across the field and made sure it wouldn’t hit the power line and it was probably 15ft from the power line. Now sometimes those lines would droop down depending on atmospheric conditions and can get as close as 15ft to the ground and we’ve walked under them before and mowed under them with them being 15ft from us and it’s no big deal. Just as long as you don’t TOUCH them you should be fine but that’s not the case.
I decided to fly first since I built the model and my brother launched it for me as I stood in the middle of the circle and when the plane was launched the power line was behind me so the plane needed to fly 180 degrees around before it got to where the power line was. The plane flew about 1/4 of the circle and it was like someone turned the lights off. This was a Saturday and I woke up Monday in the burn unit of Vanderbilt Hospital in Nashville.
While the plane didn’t touch the line, it got close enough to it for the electrons to jump to my stainless steel lines. The voltage ran down these steel lines, evaporating them as it went along, hit the handle that I was holding and jumped from the handle to my waist, ran down both legs and into the ground. No electricity ran through my upper body which is why I’m alive.
2nd and 3rd degree burns on my legs and some on my arms but these were minor. The electricity hitting ground caught the field on fire and my clothes. Numerous skin graft operations, countless dosages of Morphine and hours of therapy and I was out 3 months later but I have many lasting affects. My right leg is paralyzed below the knee. My left leg is weak but about 80% of what it was before. I use a forearm crutch to walk. I can drive a car, as long as it’s an automatic, I’m even a private pilot, so I can get around ok but I’m not 100%. I basically tell people that as long as I don’t I have to run or jump then I can probably do it.
When I was in the hospital, there was another patient who just happened to worked for TVA who was sharing my hospital room. TVA is the utility that actually owns and operates those power lines I got in a fight with. He said that in all the years he worked for TVA he’s known several people to be killed by those 161kv lines but never known anyone to survive. He was an electrical engineer and did some calculations for me. He took the length of my control lines, the diameter of the lines, temperature and humidity for the day of the accident and somehow calculated that I was hit with probably about 60,000 volts and not the full 161,000v. I also asked him why didn’t the electricity run down my arm and through my upper body ? The electricity made it to my hand but then jumped to my waist. Logically it should have just continued through my hand, my arm, and down through my body to the ground. He said it also takes the path of least resistance and for some reason it though your waist would be quicker instead of my hand. My right hand, doesn’t have a mark on it.
Anyway, stay away from those power lines as you don’t need to touch them for them to get you. I thought you had to make contact but you don’t. When my brother launched the plane he said I took a couple of steps backwards for some reason. I don’t remember doing that but that would have gotten me closer to the power lines but still not close enough for the plane to make contact when it flew around.. My brother said it looked like I got hit by a bolt of lightning.
Life goes on.
Excellent video Clive, VERY well explained without all the ramblings often found in work safety training videos ! This video could be the new industry standard for newbies.
EXTREMELY well explained! I couldn't peel away for a second!!
And for the more experienced ones who may get a bit complacent!
Sequel to"Shaking hands with danger"
When I was in high school I had an electronics teacher a lot like Clive. Everyday we'd have to start class by saying "how many amps come out of a socket? 10-12. How many amps to stop your heart? 1." Not sure if I'm remembering the socket amps correctly. Message is still the same. I like the way the American refineries do it, you have you're own lock and key, you lock the switch so no one but you can turn it back on and leave a note as to where to find you.
Clive, if this video saves only one viewer's life--it has served its purpose. You're a good man.
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.
You can get another job not another life
After watching this twice, (once for information and once for presentation) I found the information well-presented and not overly dramatic. It explains everything I believe you wanted to get across in a matter-of-fact delivery, which is what you were going for, I think.
There you go, BC, for what it's worth...
When it comes to high voltage switchgear, I've heard a lot of fatalities don't come from electrocution, but from fires and explosions in confined spaces due to faulty equipment or incorrect installation. Hence the move to more remote operation.
Very well explained. High moister - humidity in the air is another factor of the intensity of electric shock.
I truly believe your two vlogs on this, electrocution and Alzheimer’s are required viewing . You tell it as it is. Good on you!!!
It has to be said, even though it is difficult to talk about.
Thank you for sharing this incredibly valuable reality.
This information is worth a life.
Thanks for a lot of good information Clive.
I'm an electrician working in an older factory. Two of my pet peeves are old abandoned still live wires, and also old SO cables that get hard and so brittle the insulation breakes away down to bare wires. Both are daily hazards to me.
And nobody dares to disconnect an old fat cable because it could cause the whole plant to go down. I know the feeling. And the cables are of course completely undocumented.
I trained as an electronics engineer (Radar) in the RAF. Because of my own stupidity I managed to get a 50KV shock DC, My legs convulsed and I jumped back where my head contacted the wall. I woke up in hospital with concussion.
1. work with a partner whenever possible
2. take all possible precautions to isolate yourself
3. learn quickly electricity is deadly, not can be it IS.
Good coverage.
This is great advice. When I was a teen I did a lot of work with old radio gear with high voltage and had a few shocks that I will never forget. Lived to tell the story fortunately.
An excellent video, all basics for those of you who have done your 3 year apprenticeship to become electrians or electrical engineers. Unfortunately in the 90's most Technical colleges became Universities and apprenticeship's were effectively scrapped and were replaced by NVQ's where you could get level 3 in a year doing 2 days with an employer who wasn't going to offer you a place at the end.
As they say a little knowledge is a dangerous thing and they don't teach risk assessment in the way time served people do it, automatically as you look at the job and not filling lots of paperwork to say you've done it. The level of traing in electrical first aid is ludicrous now, compared to the 1980's but again Nursing is a degree course to fill in paper work not actually learn about the job. And the longer we continue to move in this direction all those who are skilled at their jobs will be retired or dead, I worry for the future hands on engineers in the future, I dearly hope I am wrong but......
One of the things that made me make this video is that the new era of one to five day slideshows masquerading as "electrical training" miss all this crucial safety information out completely. They are just corporate liability disclaimers to allow the use of cheap labour to do electrical work.
Clive, I haven't watched the entire video yet, but so far I have not seen you mention that concrete slab floors can be conductive! Using any kind of electrical or electronic appliance while standing on concrete and bare feet can be lethal. Even damp, sweaty slippers, socks or sneakers can be conductive enough to allow you to get shocked. Guitar players in garage bands or jamming in the basement are at extreme risk of electrical shock.
Guitar players are fortunate in having thick, dry skin on their fingers. I know from experience. And I remember playing in an American amp in the 70s, but we here do not have plugs, where the „polarity“ is fixed, so you have a 50/50 chance to get „live“ on your Guitar. The first touch to that guitar was a bit hot, until rotating the plug. But as said, thick, dry skin on your fingers keeps you away from instant death. You have to use drugs to get it done 😎
Not the undermine the importance of the good isolating boots or shoes. Or standing on one foot (right one preferably).
Thank you dear Clive. Very informative video.
I once experienced firing a RCD with my fingers (a 30 mA type) while standing on a ladder repairing a ceiling light.
It made me happy. I felt confirmed that my decision securing all lines with RCDs was not a stupid money expense.
Great video, thank you. I had a nasty shock recently when I inadvertently completed the circuit between my metal cooker hood and faulty hob. Hoods are usually double insulated and therefore not earthed (apparently). It turns out the hob had some kind of electrical fault and this somehow caused the hood to be carrying live voltage, possibly through leakage. It was only when I was cleaning a bit of food off the hob and bumped my head on the hood did I get the shock - bright flash in my eyes, involuntary gasp, and ears ringing; fortunately nothing more serious. Very grateful for my RCD which tripped and potentially saved my life. After an electrician disconnected the hob from the electrics the hood is no longer live.
Good Info, Clive. I am a retired TV Engineer and have had a few shocks even when I thought I as being careful. Happy holidays to you and Alfie and the beard club guys.
As soon as I saw the title, I knew it was Clive before I even saw the channel name.
Chilling topic.
Since everyone is sharing their stories...When I was a kid, I once made the mistake of testing out a 9v battery from a smoke alarm with my tongue. I'll never repeat that mistake again..thanks big Clive
I took a very unexpected shock. I was using a baldor dc motor drive for nickel plating.
I normally use it for my angle grinders, i did not buy it for plating but decided it should work well.
I installed a 10 turn pot with a counter for the current limiter so i can set the max current for different size power tools.
It did work well using around 5 to 8 volts and using the current limiter game me better consistency that voltage control.
i logically decided it would be perfectly safe as long as i do not accidentally turn the voltage higher. So i made up some wires to plug it into my fluke set to volts, and cheap meter on amps. This way i could easily double check that i am safe.
I was plating very successfully multiple times. Holding one or both leads at times. Wearing my thick sole logger boots.
Some of you probably know where this is going by now.
A total brain fart made me not realize that this is only safe with an isolated supply. This is not.
Each time i would turn the switch on, check volts, pickup the lead and connect to the part. Each time prior i would disconnect the part and set the lead down and when finished turn off the dc drive.
However the last time i used it, i powered up the same way but when ready to stop, i just reached over and grabbed the metal toggle on the properly grounded metal enclosure of the dc drive.
Instantly i felt the current through my body. From hand to hand, definitely felt it in my chest.
I dropped everything and sat down and wondered what just happened. It took me a few minutes to realize why it happened so i got my meter unhooked from its current arrangement and checked ac voltage from the lead to the grounded case. 67 volts.
I can definitely say i never want to experience that or more again.
Thanks for this comprehensive guide. There is a secondary (delayed) aspect to electrocution that you have to be wary of. Blood that does not circulate will automatically clot. Red blood cells are typically about 7.5 micron diameter by 2.5 micron thick. The smallest veins (of which we have many in the brain) are about 5 tot 10 micron. It doesn't take make much to clog such a vein. A blood clot can circulate for quite some time without doing any damage and can likely be broken down again. That is unless it gets stuck before that and then it's pretty bad.
Honestly this is more helpful than the trade school classes I took on 480v. I heard about arc flashes and everything horrible that could happen but never told anything more than don't short things, wear boots and keep one hand in your pocket. None of the electrical engineering books cover the effects of electricity on the body.
430am can’t sleep after a breakup, turned to this because your beautiful measured voice helps me fall asleep sometimes. 5:21 never thought I’d be crying myself to sleep to a bigclive vid. Props, good sir.
When working with others I have one rule; never think “no one can be that dumb”.
Because, Yes, they most definitely are.
Another shock hazard you see on older buildings sometimes are shared neutrals where the breaker for the circuit you are working on is off but it's sharing a neutral with a circuit that is still powered on. They should be on double pole breakers in this situation but often they are not in old installs and they can be a nasty surprise.
Happens in older housing as well. Common in the 60's (UK). Happened to a neighbour changing his kitchen light fitting which had a common neutral return..
In old UK factories fused neutrals were not uncommon in single phase switchgear.
Always be aware of your surroundings and trust nothing! Great video as usual. I'm not a qualified electrician, but have worked hard to be competent at what I do. I've always tried to educate people around me how to do DIY safely and when it exceeds their skill level, call a professional.
One day I was redecorating and using the opportunity to strip out any extraneous wiring (the house is an electrical nightmare). I had my daughter with me and found a switch cable buried in the wall and the box papered over. I knew that there had been a switch there, so no surprise. I was expecting this to be dead. Fortunately, I used the fact that we'd 'found' a wire as a teaching opportunity and demonstrated how to ensure this was safe before doing anything. Well, I had a red face when this turned out to be fully energised (I suspect that if alone, I'd have just pulled it out).
Resulted in having to drop the ceiling and try to find where this was connected. In fact, I was never able to determine the source and ended up boxing and terminating the wire with just about every warning I could think of.
Moral of the story - treat every encounter with electricity as a teaching opportunity, don't shortcut just because there isn't a padawan present.
One of the best explanations about electric shock and how to help prevent it I've heard. As an electrical and electronic engineer myself you have described the various scenarios and taken the drama and hype out of a subject that needs to be taken seriously.
My worst shock was from an unplugged and completely disconnected tape recorder I was servicing. I put my hand close to the capstan motor and was knocked backwards with an arm that felt like a fizzy drink bottle that had just exploded. The tape recorder had DC solenoids inside to make various mechanical movements. This was supplied directly from rectified mains voltage with a 1000uF 400V electrolytic capacitor for smoothing. Unfortunately, whoever designed the circuit forgot to put a discharge resistor across the capacitor. The result was a fully charged capacitor to around 340 volts that remained in the disconnected tape recorder for unsuspecting me.
Great work Big Clive. Always enjoy your down to earth (pardon the pun) videos.
Ouch! And I just learned that a discharge resistor is a thing.
I'm lucky somebody told me about discharging capacitors manually though, or there's a few situations could've messed me up. Electrical safety videos never even mentioned it's a thing.. or what a complete circuit is lmao "don't go near electricity mmmkayy" seems to be the gist of most of it.
My worst shocks have come from:
1. Sticking my fingers in a 240v lamp without a bulb while it was turned on, at the age of 6 (because I didn't know what would happen).
2. Sticking my fingers in a 240v lamp without a bulb while it was turned on, at the age of 7 (to test if it was on or off).
3. Bathroom lightswitch in a dodgy house where the landlord put on wigs and stuff to be different people (plumber, roofer, electriction..), would get you with even slightly moist hands.
4. Touched end of HDMI cable connected to 52 inch plasma tv (this happened so many times, but most of the time doesn't, not sure why)
5. Touched end of HDMI cable connected to PC with 1000W PSU. (this also happened so many times, but most of the time doesn't, not sure why)
6. Repairing a guitar amp within 30 minutes of waking up (I left it plugged in and touched the wire).
7. Drunken friends with stun batons.
8. Drunken me with stun baton.
not a snubbing.. but snuffing circuit..
I remember my dad having a busted PSU and he opened it trying to fix it. I told him "don't be stupid, that's dangerous" and tried to fix it myself. I touched the heatsink whilst the PSU was live and I got one of the nastiest shocks in my life. Never ever doing that again that's for sure. I'm even using resistors now to discharge capacitors instead of a screwdriver.
Cheers Clive, great video. I used to work in confined spaces surrounded by water and lots of exposed metal... the engine room of a crew transfer vessel... basically, a metal box floating in salt water that occasionally leaked. I was always weary about touching the 240v stuff. I'm a mechanic first, not an electrician. Luckily any major repairs were referred to a qualified electrician at the earliest opportunity and my experience with the 240v side didn't usually go much further than isolating equipment. Still, always made me nervous going into panels. Nothing bad ever happened but I was somewhat aware of what could happen if something did go wrong.
And then i recall ships have this whole issue with enclosed spaces where if not assessed carefully, one can go into an area which turns out is depleted of oxygen. Confined spaces are definitely something to be wary of.
Informative, clear and coherent video.
I love the "fundementals" vidleos- it's a great addition to the channel, and- as always- interesting content to watch.
Thanks, Clive :)
Had a few belts in my time but the very worst was as a callow youth; I got a brown-moment, phase to neutral from a 3 phase 400Hz 115V for military stuff in aircraft. Hurt like a b'stard and taught me valuable lessons I hold to this day, like *always* test with a multi-meter, always have the plug visibly out and on the bench in front of you if you can and even latex/nitrile gloves can protect you. The latter is why I always wear a set of "Dr. JellyFingers" in the workshop.
Great video on this subject. I am an Amateur Radio operator and find your videos really interesting. My worst shock was when I was about 10 years old. My father used to rent an industrial unit for his car bodywork business and one day I was trying to improve the reception of a tiny am/fm radio with a short unsupported wire antenna. I found a nail and a hammer and proceeded to drive the nail (to support the antenna)into the wall beside the electric meter. I remember a strong contraction up my arms and across my shoulders and then I pulled back. Only some years later I realise how lucky I was. I could not figure what happened to the nail as it had disappeared!
Back in the 90s, when I was a kid, I was playing around with an old "trouble light" (don't know if they have those in the UK, it's a handheld light on a long cord often used in shops/garages here in the US). I remember plugging it into the wall, holding it in one hand, then reaching up to turn on the circuit breaker inside the breaker box. The instant I flipped that switch, I could feel 120 volts 60Hz AC coursing through my body. I was totally frozen, I couldn't let go of the light, nor could I turn off the breaker. It must have been a fairly low current though, because I do remember being able to breathe and scream (although I couldn't open my mouth, I was screaming through clenched teeth). After about five seconds, it stopped. I don't know if the breaker tripped or if I somehow moved ever so slightly just enough to break the circuit on my own, but at least it stopped. I remember after it happened I felt like utter hell for several hours. Despite it crossing my heart, it didn't seem to cause any ill effect (double surprising since at the time I had Wolff-Parkinson-White syndrome, so my heart would have been even more sensitive to electric shock). I kinda became scared of electricity for a long time after that.
An urban legend that unfortunately seems to still spread around is that someone who has had an electric shock but is no longer in contact with the source will "retain an electric charge", and that they should not be touched because they could electrocute you. Sadly, this false belief means that some people will be unwilling to perform CPR or offer other medical assistance on someone who is unconscious after a shock.
"Trouble lights" do exist in many countries, there's nothing special about them.
Even construction workers often use them.
The only difference nowadays is that they tend to be wireless LED ones but I remember seeing the traditional ones that plugged in the mains and had an incandescent bulb when I was a child.
Fun fact: Most of those lamps (I'm talking about the incandescent ones) in my country don't even have a switch, although some "higher-end" ones do feature one.
Clive, great video as usual. It'd be great for you to do a video on how a defibrillator works, and what's inside an AED on the back of this. I'll be able to find a dead AED somewhere if you're interested.
EEVblog did a teardown of a defibrillator
I have a defib here awaiting its moment.
As a 20yr old I was sent by my employer without skills or training to fault find and repair snagged emergency lighting fixtures at major sites such as Broadgate, Canary Wharf and others in the late 1980s. I got many shocks and tingles learning unsupervised on the job. I hope things are better for young workers today.
I followed your link: another very well crafted analysis from you (particularly concerning the diaphragm). My background is as a medical engineer concerned with life support and diagnostic equipment. Under some situations it is possible to kill a patient through micro-shock with a current of 10 to 30 microamps. This occurs when an electrode is inserted into the heart, often to temporarily pacemake a patient prior to fitting a permanent one inside the chest. The electode is connected to an external pacemaker: the issue is around how much leakage current there is from equipment and the patient environment and how to avoid entry and exit paths. The business end of a cardiac monitor or ECG machine has to be isolated from earth to minimise such paths. Testing of equipment is brutal: the front end of an ECG machine is looking for about 1mV of signal and we used to zap 1000VDC down it with a megger! Death from amps, through to milliamps, and finally micro amps!
Live work was banned in Australia a few years ago. It took about 7 years solid work for the Unions to have it banned. You can choose to work on live equipment, but no one can force you to do it.
For machine repair it's almost always required to have the power on for tracing a fault through circuitry. Blanket banning of live work just makes people do it "illegally".
Great video Clive, well presented, and obviously very well researched. A lot can be learned from content like this. 10/10 and a double thumbs up from me! 👍👍
If I was to give an unofficial guide to electrocution it would be verbatim. A very accurate account getting a belt. Seen your account of contacting mains with both hands at close quarters, not pleasent.
Starting colledge as a sixteen year old apprentice (1970) we were instructed to keep one hand in a pocket when working on live equipment. Complacency is a killer.
i know a chap who was pushed out of an electric train by football hooligans onto the live line he has a rather nasty scar on his back from the negative rail , he was on the line for 20 minutes and he actually died , he is alive and well today 40 years on . A very lucky man.