Here;s a situation I came across.

I know any time a metal mounting box is used for a duplex outlet the box
should be tied to the ground wire coming in.

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?

On Apr 26, 7:39*pm, Red Green wrote:
Here;s a situation I came across.

I know any time a metal mounting box is used for a duplex outlet the box
should be tied to the ground wire coming in.

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?

Metal boxes should always be "grounded".

cheers
Bob

Red Green wrote:
Here;s a situation I came across.

I know any time a metal mounting box is used for a duplex outlet the box
should be tied to the ground wire coming in.

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?
Hi,
Floating metal box is not a good idea. If hot touches the box you can
get zapped.

"Red Green" wrote in message
...
Here;s a situation I came across.

I know any time a metal mounting box is used for a duplex outlet the box
should be tied to the ground wire coming in.

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?

It must be grounded, gfci or not.

On 2008-04-27, Red Green wrote:

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

Wayne Whitney wrote in
:

On 2008-04-27, Red Green wrote:

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.