Path: utzoo!mnetor!uunet!mcvax!ukc!strath-cs!al
From: al@cs.strath.ac.uk (Alan Lorimer)
Newsgroups: sci.electronics
Subject: Re: Automobile shock hazard (was: shock box)
Message-ID: <888@stracs.cs.strath.ac.uk>
Date: 21 Mar 88 09:36:27 GMT
References: <560001@hpcljws.HP.COM> <334@eos.UUCP> <5773@watdragon.waterloo.edu>
Organization: Comp. Sci. Dept., Strathclyde Univ., Scotland.
Lines: 30
Summary: Vehicle 12V - you can hurt yourself

In article <5773@watdragon.waterloo.edu>, gvcormack@watdragon.waterloo.edu (Gordon V. Cormack) writes:
> In article <334@eos.UUCP>, jbm@eos.UUCP (Jeffrey Mulligan) writes:
> > From article <560001@hpcljws.HP.COM>, by jws@hpcljws.HP.COM (John Stafford):
> > > I wouldn't quite claim it is safe to work at automobile voltage (12V)
> > > levels.  The second factor, current, comes into play here; cars may only
> > > be 12 volts, but there are (especially when starting) quite a few amps
> > > around.
> 
> Give me a break!  12 volts is absolutely safe.  Reminds me of when
> people kept fiddling with my science fair project (a long time ago), 
> so I put up a large sign:
> 
The 12V supply in a car is quite capable of delivering currents of the
order of several hundred Amps. Ok, so what can happen? Well I heard
of an accident happening to someone a few years ago, whereby the
bracelet of his watch became welded accross the starter motor
terminals. 

The current in the bracelet cause it to heat up (it became red hot in
fact) leading to severe burns. When I heard this I thought that this
must be a pretty unlikely type of accident, and that it would be a lot
of trouble to arrange such a situation. Until it happend to me too.....

I would agree that 12V is safe from the dangers of electric shock,
but please be aware of the dangers of low impedance sources, and take
care to remove any jewelry before starting work.
-- 

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