[SML] Man's Wedding Ring Gets Him Killed

[e-mail frank.wood95]

It is quite difficult to fatally electrocute yourself, with ordinary
mains voltages. You need a current of over 30mA to do it, and for some
time over 30mS. That was the rating for ELCBs (GFCIs). This means a
good connection, both to the source and to the ground, or to the other
pole of the supply.

I live in 230V-land, where a less good connection is needed. Even so,
it is hard. A good friend of mine was once foolish enough to lay hold
of a faulty electric kettle and the cold water tap at the same time.
He retained his persence of mind, and, being a scientist and in spite
of the involuntary muscular contractions, managed to touch the kettle
to the tap, blowing the fuse.

Myself, I have a high skin resistance. I have, through my own
carelessness, met 230V several times. All I have ever done is to
remove my fingers sharply, and speak a few profane words.

Rings and metal watch straps are a different question, particularly
where heavy current sources are available, such as lead-acid
batteries. Telephone systems used to have huge central batteies of
lead-acid cells to power them at 50V. I remember visiting one such,
which was about 30' x 10', full of them, interconnected to provide the
standard 50V. All tools had to have an insulating covering, as far as
was possible, and it was absolutely forbidden to have a metal ladder
in them. Wooden ladders were the rule.

On 12 November 2014 22:51, Dave Vick via Stagecraft
<stagecraft at theatrical.net> wrote:
> On Tue, Nov 11, 2014 at 2:11 PM, Jeffrey E. Salzberg via Stagecraft
> <stagecraft at theatrical.net> wrote:
>
>> http://www.newser.com/story/198469/mans-wedding-ring-gets-him-killed.html
>
>
> The thing that bugs me about this story is... You need a ground path
> to complete the electrical circuit through your body; *that* is what
> puts you in danger. Just removing your jewelry isn't enough. Okay,
> sure; I can buy the guy's ring made contact with an unseen source of
> 208VAC, but where did the juice EXIT from? Was he kneeling in water?
> Was he also grabbing a metalic (grounded) drain pipe? What's the rest
> of the story?
>
> "Just take off your rings" sounds more like good advice for carpenters
> and machinists than it does for electricians, frankly, in the absence
> of other data.
>
> --
> Dave Vick
> Automation Carpenter/Rigger,
> "Dirty Dancing" North American Tour '14-'15
> 517-749-3859
>
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-- 
Frank Wood