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Posted by Red Green on April 27, 2008, 8:10 pm
>
>> What if the metal box/outlet is on the load side of an upstream
>> GFCI? Maybe codes say it still has to be grounded (?) but from a
>> safety standpoint is it pointless to ground the metal box?
>
> As others mentioned, the NEC requires it to be bonded (connected to an
> EGC). And there is an advantage to this even when the conductors are
> GFCI protected.
>
> Suppose the hot conductor faults to the box. If the box is bonded,
> this will immediately create a short circuit and trip the circuit
> breaker or GFCI. If the box is not bonded, nothing will happen until
> you come along and complete a circuit with your body. If your body
> connects the box to ground, this will trip the GFCI; but if your body
> connects the box to neutral, it won't trip. Moreover, the hot
> conductor to box fault could persist for a long time, long enough for
> a second failure to occur, such as the GFCI going bad. Then there
> would be nothing to protect you.
>
> Cheers, Wayne
>
It all makes sense. It could happen and probably has at some point and
that's why it's required like so many things that may not seem to make
sense.
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