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From: jfa0522@hertz.njit.edu (john f andrews ece)
Newsgroups: sci.electronics
Subject: Re: Stray Voltage in the hot tub
Message-ID: <1991Apr24.193756.29496@njitgw.njit.edu>
Date: 24 Apr 91 19:37:56 GMT
References: <4686@orbit.cts.com> <91113.143901FC138001@ysub.ysu.edu> <1991Apr24.024228.25848@netcom.COM>
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In article <1991Apr24.024228.25848@netcom.COM> gandrews@netcom.COM (Greg Andrews) writes:
>In article <91113.143901FC138001@ysub.ysu.edu> FC138001@ysub.ysu.edu (Phil Munro) writes:
>>> ...
>>>it was eventually determined that the tub was floating, electrically, 
>>>at some distance above ground, and the potential in it was getting there 
>>>due to some potential gradient (in the soil?) coming from the power lines.
>>>This sounds like 'stray voltage' to me, but I still don't quite understand
>>>the mechanism.
>>>

stuff deleted to appease the campus mail server...

>
>The most likely source of the charge is the wall power to the pump.
>If there were no ground supplied to the pump, or the ground wire is
>"grounded" at a point far away from the dirt around the hot tub 
>(e.g. through a long extension cord), then you could have this problem.
>
>-- 
>.------------------------------------------------------------------------.
>|  Greg Andrews   |       UUCP: {apple,amdahl,claris}!netcom!gandrews    |
>|                 |   Internet: gandrews@netcom.COM                      |
>`------------------------------------------------------------------------'

And if indeed this were the case, a simple copper grounding spike on-site,
(metal-tub-frame to earth beneath the concrete slab) solves the problem...