Grave electrical accident happened yesterday, May 25 2014

[bob p]

Juan, thanks for posting that link. I've lived through an electrocution experience. The AC shock put my muscles into tetanic contraction and I couldn't let go of the source. I know exactly what that fellow went through. I pray that it never happens again.

That's why I'm sort of an electrical safety Nazi. I'm sure that some people here might remember some of my rants against power scaling implementations that put high DC voltages on front-panel pots.

I recently ran into a fellow from one of the Carver audio forums who was from Brazil, who had bought a used Sunfire amp via Ebay that was improperly wired with a hot neutral. He was moving within Brazil, and he needed to learn what kind of power cord modifications would be necessary with his new amp. He supplied some interior shots of his amp, which made it evident that the amp was mis-wired with a hot neutral. He lived in one of those areas that used 2-prong wiring with no ground wire. It seemed that the hot-neutral wiring in the amp escaped everyone else's attention. I told him the amp was unsafe and I told him not to plug in the amp until he had the amp re-wired and certified for safety.

What was really odd about the situation is that there were a number of people on the Carver audio forum who professed that the wiring was original, and that the amp was unmodified, and that I needed to STFU.

I thought that situation to be somewhat peculiar, as the amp had been sold with UL and CE certification stickers, and there was no way that the amp would have passed UL or CE certification with a hot neutral. If indeed those amps were un-modified original designs, then there has to be something fishy about the combination of the wiring and the certification stickers. Because the company had been defunct for a long time, we were never able to get to the bottom of it all. but if those amps were truly unmodified, then one has to wonder if Sunfire might have sold a batch of amps that had been miswired at the factory after they had obtained UL Certification for the design. I'm not sure if the CE sticker on the amp was even valid -- I'm not sure of the timeline, but I'm thinking that the company might have ceased to exist before the advent of the EU, which would mean that the CE stickers on the ebay amp were fake.

The moral of the story -- be vigilant about checking wiring on every device that you hook up, and evertying that you buy in the used market.

[Tom Phillips]

... I've lived through an electrocution experience...

Wow Bob. How long were you out and how were you revived? Do you remember anything about the experience while you were gone?

[bob p]

Sorry, but I didn't have a "light at the end of the tunnel" experience that I can relate to you. I was never out. I was fully conscious the whole time.

I guess this topic merits another anecdotal story:

I was drilling holes to mount a rain gutter with a 3-wire Milwaukee power drill that was properly plugged into a 3-wire extension cord on a properly wired outlet, but the drill had a fault in it's power cord. It was a hot day, I was wearing shorts, and I was sweating. I was standing on an aluminum ladder and I became grounded through my legs contacting the ladder. The sweat was enough to lower my skin impedance, and when the metal drill chassis went hot the current went in through one hand and out through my leg.

BZZZZT!

Lucky for me only one hand was involved and the other hand was not grounded, so the current never passed across my chest. It passed through one arm to my leg, which was poorly grounded, but grounded nonetheless. When I was on the ladder the contractions in my arm and leg were strong enough to cause me to lose balance and fall off of the ladder. The buzzing stopped for a moment while I was in freefall, and I tried to let go of the drill but my muscles were in spasm and I couldn't let go...

When I hit the deck I got really well grounded, and my finger was still siezed onto the trigger so the buzzing never stopped, it only got worse.

BZZZZT!

The current was strong enough to put my arm and leg into violent contraction. It felt like I was falling in slow motion as the electricity caused all of my muscles to contract. I remember trying to let go, but being unable to do anyting about the buzzing. I was fully conscious and alert the whole time. I was fully aware of what was happening and how it was likely to end. The scary part was that t I understood exactly what was happening and there was nothing that I could do about it.

Lucky for me the current path was never directly across my chest (ie: in one arm and out the other), so my heart wasn't stopped and I never passed out. I did lose all control of my arm and leg muscles -- they were fully contracted with the 60 Hz buzzing that was going through my body and causing all of the muscles in my arm and leg to contract violently. Although the current was primarily on my left side, my right arm and leg were still unusable.

As a kid, did you ever feel that 60 Hz buzz on your fingertips when you pulled a lamp cord out of a socket? It was like that going through my whole body as all the muscles contracted together. I tried to fight it, but I got nowhere -- there was nothing that I could do to stop it and I just crumpled up into a ball. The only reason that the event ended was because when I fell to the ground, the faulty device eventually got yanked out of my hand because the cord had pulled tight as I rolled a bit during the fall.

It was one scary as hell experience, because I was fully aware of what was going on, and I knew how the situation was likely to play out. Lucky for me, I managed to have the device knocked out of my hand.

I don't like to use electric power tools outside any more -- the outside world is just too well grounded. I also don't like to use any metal cased power tools. I've replaced all of our old Class I chassis power tools with tools that have all-plastic bodies and have a double insulated Class 2 chassis. I also upgraded the wiring in the house so that all of the outlets located outside and near exterior doors that might have an extention cord plugged into them now have GFCI on them, not only the outlets in the basement, bathroom and kitchen as required by code. And when it comes to working outside, I prefer to use something that has gas power or battery power, no electricity. I absolutely hate battery powered drills because they don't have any real power, but they are better than the thought of getting electrocuted again.

Do you remember that rule to only grab a potential power source with only one hand, and to always keep the other hand free, like in your back pocket? That rule saved my life.

[Ted]

I was fitting an IEC Inlet to a 70s 20W Marshall head a few weeks back. (The original Bulgin connectors no longer pass our mandatory Portable Appliance Test). Didn't take much notice of the wire colours as I took out the old connector. When I fitted the new one, I noted that the wires were Black, Black and Green. I checked the black wire back from the fuseholder. That's Live in a UK wired Marshall. The Green must be earth. So the other black is Neutral. Plugged it in. Worked fine. Handed it back to the customer.
The first time he plugged it in it took out the house RCD. Green was neutral. I'm sure you can work out the several morals of this story for yourselves.

[Tom Phillips]

Sorry, but I didn't have a "light at the end of the tunnel" experience that I can relate to you. I was never out. I was fully conscious the whole time...

OK. got it. I was going by the traditional definition of "electrocuted" meaning shocked until dead.
Tom

[bob p]

got it. but I'll throw out the response that everything that was necessary and sufficient for death to occur was taking place -- continuous shock, involuntary muscle contractions, unable to move/breathe, etc. if the events would not have been interrupted, death was guaranteed. the only reason i'm here to type this right now is because the cord yanked the drill out of my hand. that's close enough for me.