Path: utzoo!utgpu!watmath!att!bellcore!rutgers!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!hplabs!hpfcdc!hpislx!hpmtlx!heumann
From: heumann@hpmtlx.HP.COM ($John_Heumann@hpmtljh)
Newsgroups: sci.electronics
Subject: Re: Re: Touching a "hot" connector
Message-ID: <880007@hpmtlx.HP.COM>
Date: 7 Aug 89 17:49:30 GMT
References: <427@edai.ed.ac.uk>
Organization: HP Manufacturing Test Division - Loveland, CO
Lines: 22


> 120 and 220 ARE both *potentially* (no pun intended) lethal, but you're more 
> likely to get into trouble with 220 - as it can force a deadly current through 
> a higher-impedance load, meaning that you don't have to be in *quite* as good 
> contact as you would need to check out for good on 120.  I = E/R, so any time 
> you set up a situation where you can get 100 mA through the heart, well, 
> please smile and leave a happy-looking corpse.

I believe your presumption that all currents above a threshold are lethal 
is incorrect.  What I recall is that currents within a fairly narrow
range induce ventricular fibrillation and are potentially lethal.  Once you
exceed this range, higher currents are actually LESS dangerous since they
cause simple tetany rather than fibrillation.  (Of course if you go to really
high currents you can literally fry, but now were talking about lots of
kilovolts).

I'd agree that 220/240 if generally more dangerous given typical skin
resistance but 120 should still be treated with respect.  I've even heard
of accidental fatalities from 10-20V supplies when a low resistance contact
was accidentally made.  

-jh-