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From: feldman@urbana.mcd.mot.com (Mike Feldman)
Newsgroups: sci.electronics
Subject: Re: using the bathroom during lightning storm
Message-ID: <1991Jun7.144914.21666@urbana.mcd.mot.com>
Date: 7 Jun 91 14:49:14 GMT
References: <1524@cvbnetPrime.COM> <1991May24.210108.9982@solbourne.com> <16288@smoke.brl.mil>
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In article <16288@smoke.brl.mil> chidsey@smoke.brl.mil (Irving Chidsey) writes:
>In article <1991May24.210108.9982@solbourne.com> imp@solbourne.com (Warner Losh) writes:
>>
>>Correct me if I'm wrong here, but isn't the metal plumbing in your
>>house grounded?  Is that why the house's electrical system is
>>sometimes grounded to the plumbing?  And since it is grounded,
>>wouldn't it have a zero or near zero potential?  So there is no
>>problem.  However, other examples that have been given assume the
>>"object" is much different than ground potential.
>>
>>Warner Losh		imp@Solbourne.COM
>
>	Plumbing is not a reliable ground!  PVC tubing does not conduct
>appreciable ammounts of electricity.  Even copper pipe may have insulating
>sections put in to stop ground currents from causing electrolysis.
>
>	The problem is not whether you are grounded or not, it is whether
>you are in a significant ground path that happens to conduct electricity.

A few years ago, our house took a bolt through the sewer vent, which is
cast iron and lead and had(!) a ground wire running from the TV antenna
to the roof vent.  The gook in the upstairs bathroom trap was on the
bathroom ceiling, the bathtub drain started leaking, and some of the leaded
joints in the cast iron were melted and blown through.  There was even a
chink of plaster blown off of the pipe chase in the kitchen.

It took the ozone smell hours to go away.  This happened in the early morning
just minutes before my normal visit to the bathroom.  Now, every bathroom
visit during a storm prompts me to imagine a bolt climbing the conductive
fluid stream!
-- 
Mike Feldman, Motorola Computer Group,     (217) 384-8538, FAX (217) 384-8550
Urbana Design Center	1101 East University Avenue,  Urbana, IL   61801-2009
UUCP:  ...!uiucuxc!udc!feldman,  	Internet:  feldman@urbana.mcd.mot.com