Two pole gfci breaker on mwbc

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ritelec

ritelec

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Jersey
I’m sure this has been covered many times but I can’t find the definitive answer.

A buddy of mine asked if a 2 pole gfci breaker can be installed in and existing panel on a mwbc with no gec for those two circuits? Would it work ?

We are both assuming it will but I would like to confirm.

Thank you.
 
ritelec said:
I’m sure this has been covered many times but I can’t find the definitive answer.

A buddy of mine asked if a 2 pole gfci breaker in and existing panel on a mwbc with no gec for those two circuits would work ?

We are both assuming it will but I would like to confirm.

Thank you.
Click to expand...
GFCI's don't look at "ground". They look for imbalance in current in the conductors they are monitoring. For a single pole unit - what goes out on one conductor must come back on the other. If off by more than 4-6 mA it trips.

For a two pole unit what goes out on one conductor must come back on either or both the other conductors - think of it as a clamp on ammeter that is accurate down to mA levels, if you clamp around all three conductors and have a reading of more than 4-6 mA, it trips. Basically same thing with a three pole unit also.
 
ritelec said:
I’m sure this has been covered many times but I can’t find the definitive answer.

A buddy of mine asked if a 2 pole gfci breaker can be installed in and existing panel on a mwbc with no gec for those two circuits? Would it work ?

We are both assuming it will but I would like to confirm.

Thank you.
Click to expand...
No "GEC", I think you meant EGC.
 
Obviously a 2-pole GFCI breaker would need a load neutral terminal to use it with a MWBC. I believe the vast majority of 2-pole GFCI breakers have a load neutral terminal, but the QO260GFI does not. There may be others that way as well, and so it's worth checking just to be sure.
 
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