Just in from Square D [RE-wrenches]

[hugh piggott]

<x-flowed>At 6:10 pm -0800 10/3/01, Drake Chamberlin - Electrical Energy wrote:
>
>With ungrounded systems, one conductor accidentally coming in 
>contact with ground wouldn't blow the breaker.  It would take both 
>wires touching either ground or each other.  A 2 pole breaker 
>wouldn't solve the problem, either.

A 2 pole breaker is safer than a single pole one, because one of the 
supply terminals (upstream of the breaker) might accidentally become 
grounded at source without being noticed.  Whichever one became live 
(hot?) would then be protected.  I always assumed this was the reason 
for requiring a 2 pole breaker.   If there is another reason, I'd be 
interested to hear it.

I like ungrounded systems where there are 120V battery terminals to 
work on.  But I suppose it would be safer to treat them all as 
potentially live (hot).
-- 
Hugh

Scoraig, Scotland
http://www.scoraigwind.co.uk

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