On Sat, 26 May 2007 16:25:33 GMT, (Beachcomber)
wrote:


In the 1960's, the manufactures of washing machines included an extra
ground wire and a strap for the cold water pipe to insure grounding
although it was later determined that this violated the single point
ground doctrine if the device was already grounded through the plug.

Why would there be such a doctrine? What if the ground through the
plug fails, but the other two wires don't. One wire has to fail
first: it might be the ground. Or, what if the ground fails
between the outlet and the fuse or breaker box.
Or what if the outlet has 3 slots,
and will accept a 3-prong plug, the outlet is not grounded at all.

Why shouldn't there be a second ground?

It's not a religious doctrine that was revealed by God, so shouldn't
it yield when there is a good reason.

I read somewhere that this might still be a code requirement in
Canada. ??? Perhaps someone can clarify...