Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!att!alberta!calgary!cpsc!hermann
From: hermann@cpsc.ucalgary.ca (Michael Hermann)
Newsgroups: sci.electronics
Subject: Re: Touching a "hot" connector
Keywords: touch, sensation, live, shock
Message-ID: <1496@cs-spool.calgary.UUCP>
Date: 9 Jun 89 17:21:52 GMT
References: <89Jun8.160452edt.10877@ephemeral.ai.toronto.edu>
Sender: news@calgary.UUCP
Reply-To: hermann@cs-sun-fsd.UUCP (Michael Hermann)
Organization: U. of Calgary, Calgary, Alberta, Canada
Lines: 30

In article <89Jun8.160452edt.10877@ephemeral.ai.toronto.edu> dudek@ai.toronto.edu (Gregory Dudek) writes:
>
>    I noticed long ago that if you (accidentally) touch a live
>conductor, there is an odd sensation reminicent of a rough surface.
> (the feeling is kind
>of line a high-freq. vibration -- 60Hz?).

	I'm assuming that besides doing this by accident, you were very well
insulated and so your body did not provide a ground fault to the conductor
(ie. no current went a significant distance through you).
	I've done the same thing, and I think that it must be a sensory
distortion caused by the conductor current. Part of your finger becomes
a current carrier, but only at the surface, just as with any other conductor.
The tactile nerves in the skin could then be overloaded, to the tune of
about 60Hz, and provide you with the illusory sensation of a 60Hz vibration
in the conductor you are touching.
	I can't explain why the nerves concerned with detecting pain or
temperature changes are not similarly stimulated. 

	If you are unfortunate enough to unplug a lamp the _wrong_ way,
you will find that your hand and lower arm are subject to a much more
palpable _thrumming_ at about 60Hz, which is partly the current, but mostly
you arm and hand muscles being stimulated by the current and contracting at
60 Hz. This is an unpleasant sensation, but not painful at all; once is
enough however. 

|  Mike Hermann  | ..!uunet!ubc-cs!calgary!hermann calgary!hermann@cs.ubc.ca
Organized Religion is like Organized Crime; it preys on peoples' weakness,
    generates huge profits for its operators, and is almost impossible
    to eradicate.   -- me