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Posted by Mark Lloyd on July 18, 2006, 10:24 am
wrote:
>On Mon, 17 Jul 2006 15:47:06 GMT, Wayne Whitney
>
>>
>>> If an outlet is GFI, does equipment ground still serve any useful
>>> purpose?
>>
>>Yes. With an EGC, equipment that develops an internal ground fault
>>(e.g. to the chassis) will trip the breaker. With a GFI only, the
>>equipment chassis will remain hot until someone comes along and
>>provides a path ground to trip the GFI.
>>
>>Also, redundancy usually improves safety. GFIs fail alot more often
>>than the EGC.
>
>Because GFI's have to do something, something mechanical I think, for
>them to work.
>
I'd guess a latching relay that can be put in one position
electrically (tripping), but requires mechanical action (reset button)
to return to the other state.
>The equipment ground is just a wire connected to the chassis. It's
>there all the time.
>
>Also, who can be sure that one will always use any electrical device
>from the same outlet all the time? (unless it's a furnace or water
>heater, or ok, ok.... These aren't GFI outlets anyhow, iiuc.)
>
>>Cheers, Wayne
--
Mark Lloyd
http://notstupid.laughingsquid.com
"Democracy is two wolves and a lamb voting on what
to have for lunch. Liberty is a well armed lamb
contesting the vote." - Benjamin Franklin
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