Electric Shock

[antcollinet]

For me when I experienced the hair standing up stuff I was so intrigued and amazed by the storm that it took me a minute or two to get my butt back inside the house. I suppose I looked like one of those idiots in a movie that everybody is annoyed at for being near the forthcoming death and not having the sensibility to get outta there.

That's what I was thinking you looked like when I was reading your story.

 

[KellenVancouver]

Way too many to relate, and some very sad (injuries and deaths). I still have a scar on my wrist from a TV anode arc that leaped to my watch (which I usually removed at work, stupid). A sadistic parts store owner was known to charge a big axial cap, bend the leads back over the case, and toss it to folk for the shock effect. The usual tales of rooms filled with bits of foil and plastic from wiring a big electrolytic backwards. Etc.

Lightning, many tales, but the scariest I recall was a storm moving in whilst my boss and I were trying to finish erecting a TV antenna tower. We saw it in the distance, then a lightning strike hit the ground still very far off, but all the hair on our bodies lifted. Fastest we ever got down -- tied off the antenna to the tower and dropped! Then the time I waited out a mountain shower at home and after it moved east, with clear blue sky overhead, went to light the charcoal in the grill for supper. A bolt hit a tree about 50' away, out the blue, and showered the deck (and me) with bits of bark. Broiled steaks in the oven that night...

That's the problem with lightning, it has reach beyond the visible horizon. There are some rather tall tales of lightning striking 100 or even 200 miles away from the actual storm, but I believe a reach of 20 to 25 miles is more the norm. Still, that blue sky overhead is no guarantee of safety...

 

[HammerSandwich]

Most memorable was a shifter kart's ignition coil which somehow leaked into the frame rails when the HV lead failed. I got hit quite a few times where my leg touched the steering hoop, before I could pull the clutch in & lock the brakes. 10s of kV will definitely get your attention.

My father had a good career as a lawyer, but he's the least competent person I've ever seen work with tools. (Ping me when that's a thread.) Many years back, I walked into his kitchen while he was trying to replace the "instant hot water" heater under the sink. Can't recall exactly what the difficulty was, but I vividly remember asking him to confirm that the line power was off before I took over. "Of course, absolutely." Bam! &#$^!!! "Say, dad, you might want to double check that the power's actually off before you finish installing that thing."

Last one, thankfully vicarious: my high school's physics lab had an air track for measuring linear motion. A long paper strip ran along the track, and a timed spark burned holes in it to indicate the sled's position. Of course, some jackass decided to pop a couple sparks while someone else was fiddling with the paper. His victim screamed, "jumped" off the 40" bench, fell all the way to the floor, then staggered to his feet, looking like a much older man. With grey hair. He had curly hair, and the last 1/4" was just ash.

 

[JJB70]

When I worked in electricity HV safety incidents were as rare as rocking horse turds, LV incidents were also pretty rare (the safe system of work in UK power plants is or at least was very stringent) but they did happen occasionally, usually with no injuries resulting. The reason is party that work and test controls were more stringent on HV (and not everyone was authorised for HV) but more fundamentally there is a respect for HV and people know you only make the same mistake once with HV (in UK power plants HV is 1000V and above, we do not have the MV tier used in some countries). I've had a few shocks from LV instrument systems (12V DC) which despite the low voltage can be quite nasty, though never been zapped by anything higher.

 

[mansr]

I've had a few shocks from LV instrument systems (12V DC) which despite the low voltage can be quite nasty, though never been zapped by anything higher.

Regulations vary, but in general anything up to 50 V or so is considered low voltage and safe to work around without special precautions. Safe doesn't mean it can't give you a bit of a tingle, though. An educational experiment is to connect a variable lab power supply to ones hand, then crank up the voltage until starts getting uncomfortable. With wet skin, it's sooner than you might expect.

 

[puppet]

When I moved to Wisconsin I started a small cab/furniture shop outside of town in an old barn. In springtime around here moisture tends to settle everywhere. The lower part of the barn was especially damp during the season and strong storms where the norm. One day my dad and I where in the lower part of the barn when it got hit by a lightning strike. The metal roof was grounded but the flash traveled through the barn along the floor ... looked like a blue wave. We both looked at each other and headed for the house. Never seen anything like that.

 

[Spkrdctr]

Lightning does some weird interesting stuff. It jumps fairly large air gaps that you would think would isolate equipment/circuit boards. It will travel through the circuit board ground traces and destroy whatever it feels like and leave other items untouched. It is a circuit boards Grim Reaper!

 

[antcollinet]

Lightning does some weird interesting stuff. It jumps fairly large air gaps that you would think would isolate equipment/circuit boards.....

It has jumped though an airgap measured in miles from whereever it started to your equipment. A few mm or cm or inches or feet or meters of airgap once it gets there are not going to worry it - even a little bit.

 

[mansr]

Lightning does some weird interesting stuff. It jumps fairly large air gaps that you would think would isolate equipment/circuit boards. It will travel through the circuit board ground traces and destroy whatever it feels like and leave other items untouched. It is a circuit boards Grim Reaper!

Once upon a time, I had a job repairing studio photo flashes. Those things are a miniature thunderstorm in a box. Sometimes, the lightning would take the wrong path and vapourise anything in its way. I saw PCBs with only a charred hole where a component with an indeterminate number of pins had been. Real lightning, being a million times more powerful, is something I hope never to encounter close up.

 

[Ingenieur]

I've been shocked once. Early in my career troubleshooting a 480 VFD in a data center.
Bit by 277. Stunned for a minute, no burns.
Took a few minutes to shake it off.

I have seen horrific results of electrocutions as part of my job performing accident investigations.
It is always human error, >90% lockout/tagout/verify absence of V.

Arms needing amputated due to putting a meter set to I on 600 VDC

One involved a guy hit by 13.2 kV, when they lowered the bucket he staggered around and burst into flames.

A guy hooked up on 25 kV...for 3 hours.
They did not have a long enough hot stick to pull the pole disconnects.

This guy lived. Used a Cat III meter on 2400 VAC to check phase rotation. The same tool box had the right tool. It arced blowing 2x400 A fuses and a 69 kV primary xfmr fuse 1/2 mile away. The conductors were 'dancing'. The facility is a large underground storage facility and data center. VERY stiff redundant power supplies.
He had all the proper PPE on and only sustained minor eye arc flash burns.
The meter leads evaporated and the suit was toasted.

But most fatalities:
A small burn at exit (like a sun burn).
Tiny hole at entry, like a pin prick, often just another light burn.
Often, no marks.

 

[dfuller]

Took 300 volts or so from a guitar am I thought was discharged. Turns out it had a blocking diode in the preamp's high voltage power supply for some reason. That was fun, especially because it was across my chest.

 

[Willem]

I never experienced electrical shock, but my father was an electrical engineer working with industrial voltages and he educated/drilled us extensively and repeatedly. I will never work on any anything electrical without disconnecting the power, and testing the result. Personally my father was very careful, and aware of the risk for his personel. Even so, over the years he lost one electrician who, indeed, had been careless, notwithstanding the repeated instructions. It is odd how overconfident people can become. My father would walk into the factory from time to time, just to make sure people knew that safety mattered. Anyway, I think I have inherited the drive: I will never wear loose clothing working with power tools, will use eye and hearing protectors, safety gloves and a helmet with visor when using my little chainsaw, etc.

 

[BostonJack]

I worked, many years ago, on phototypesetters, as a systems tech. My job was to do final assembly, photo alignment, and checkout. The machine had a high voltage supply that was adjustable, which involved reaching in with a plastic screwdriver and setting the high voltage to 1.7 kV. I got hit once on the back of the hand (it was a tight space). The hit was: automatic retraction of arm, forced exhalation "Huh", followed by standing there and turning white as a sheet. Every tech in the department did it once. I don't think anyone did it twice.

I did spend some time playing "chicken" with my cousins on an electric cattle fence. We would face each other and grab the wire between its barbs. Every 1.5 seconds or so we would get hit by a pulse. First one to let go was chicken. Stupid.

The more fun way to play with an electric fence was to pluck a 12 or 15" stalk of grass and lay the end on the fence. You could tune the shock by moving the grass further up the stock. At 6" or so it was pretty strong.

 

[mansr]

I will never work on any anything electrical without disconnecting the power

That's not always an option.

 

[Ingenieur]

There is a difference between 'working on' and troubleshooting.
That is why compartments are separated/isolated and controls are typically what is considered non-lethal V levels or have sensitive GFP.

Engineering controls can prevent most issues. In the example above he did not need to check phase rotation live.
He could have looked at the protective relays for source and generator.
If not matching, switch outside lead.

I have never seen an electrical accident that could not have been avoided.
Shoes, mats, gloves, task training, wrong guy for the task, proper PPE, proper tools, etc.

People think they are smarter than they are and are faster than electricity. Another faction takes short cuts or just doesn't understand the hazard.

 

[Spkrdctr]

People think they are smarter than they are and are faster than electricity. Another faction takes short cuts or just doesn't understand the hazard.

Yes and double YES. People also think they can hear better than test equipment. Pure self indulged poppycock. Put any person who claims they can hear most stuff and they fail listening to stereo in a real room. 100% failure rate. Amir's trained listening and his ultra short listening clips and possibly test tones are the correct way to do it for "engineering level" testing, but for all of the consumers in audio land? Nope, what Amir hears will never be heard in any living room with music. So, he tries to give us a subjective review that is nice and short and it is usually with one speaker. Give him two speakers and he has mentioned it then becomes almost impossible to tell things apart. It's all generalities and the test charts. Read the charts and take Amir's advice to see if the speaker interests you at all.

 

[JJB70]

I have seen horrific results of electrocutions as part of my job performing accident investigations.
It is always human error, >90% lockout/tagout/verify absence of V.

In my opinion incidents are seldom the result of human error when properly analysed, I find human error is a classic example of something which tries to answer everything and in trying to do so answers nothing. Human error is often attached to systemic failures, including inadequate management oversight, a safe system of work which is not fit for purpose, commercial pressure over riding safety management, inadequate training, poor work control, bad design and ergonomics and much else. I'm struggling to think of an incident I've investigated for which I'd make human error a principal cause, though I can remember many where the initial reaction of many was to blame human error.

 

[Thunder22]

Over the years I've been hit with 110v a few times. It will give you a tingle that's for sure, but when you get kissed by say 277v, then it starts moving you around. The one time I felt 277v , my hand moved so fast inside of a heat pump compressor cabinet that I am not sure what was worse the shock or the impact of my hand hitting the cabinet.

Do yourself a favor and never work on live electricity over 200v unless you are a trained professional. I work with and around a lot of 460v/3 phase equipment, but would never work on it live. That shit can kill you or at least make you wish you died.

 

[Ingenieur]

In my opinion incidents are seldom the result of human error when properly analysed, I find human error is a classic example of something which tries to answer everything and in trying to do so answers nothing. Human error is often attached to systemic failures, including inadequate management oversight, a safe system of work which is not fit for purpose, commercial pressure over riding safety management, inadequate training, poor work control, bad design and ergonomics and much else. I'm struggling to think of an incident I've investigated for which I'd make human error a principal cause, though I can remember many where the initial reaction of many was to blame human error.

I have been investigating accidents for decades.
I 'properly analyzed' all MSAH and OSHA fatalities since 1990 to develop a new safety law and >90% were human error by the victim.
Lockout/tagout/verify absence of V

They all had training
The engineering controls were in place
The individual is responsible for his work habits and personal safety
LO/TO/verify is drilled into them
In fact if observed by an inspector, they are cited and lose their papers
If by management, disciplined, and if repeated, terminated

We have to stop blaming others for our actions.

If you have never investigated an accident where the victim caused his fatality you have never investigated an accident.

What agency do you work for?
I am the principal in charge of investigating accidents for a state LE Bureau, I supervise Inspectors.

Example:
The last one.
Power centers have l cover switches.
When a cover is removed it trips the upstream feeder.
A worked removed a cover.
He then jumpered out the switch
He reset power
He then stuck his arms into the internals
12470/7200, bad result

He broke the law bypassing safety devices. He was troubleshooting the switches. That could be done de-energized.
He had 20 years experience
A certified electrician
A supervisor who conducted safety training
It was an off shift, no production pressure

 

[JJB70]

I have been investigating accidents for decades.
I 'properly analyzed' all MSAH and OSHA fatalities since 1990 to develop a new safety law and >90% were human error.
Lockout/tagout/verify absence of V

They all had training
The engineering controls were in place
The individual is responsible for his work habits and personal safety
LO/TO/verify is drilled into them
In fact if observed by an inspector, they are cited and lose their papers
If by management, disciplined, and if repeated, terminated

We have to stop blaming others for our actions.

If the safe system of work isn't working then that's a systemic failure. Why is it some organisations have virtually no electrocution incidents? Safety systems should be resilient to human failure. During my time in electricity generation (including managing multiple cross boundary interfaces with the transmission and distribution systems) safety incidents were vanishingly rare and I never saw one that was attributed to human error. Incidents were (and remain) more common at sea, the difference isn't that generation employed people that didn't make mistakes but rather their risk management controls and safe system of work was far superior.