SABC/altenate GFCI's

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jute

Senior Member
Location
SO CAL
Hello.
I have (8) kitchen countertop receptacles in a kitchen remodel... At the time I have 12-3 w/ grnd running from the first j-box to the last j-box. My question is...can I install a MWBC (12-3 w/ grd) from the panel to the first j-box to control (2) sets of GFCI Protected outlets so I can alternate circuits between them.. I need to have GFCI #1, #3, #5, #7 on the first circuit and GFCI #2, #4, #6, #8 on the second circuit fed by a single MWBC...I know I could run a MWBC and alternate receptacles on it but can (2) sets of GFCI's share the same neutral??? Thanks, JB
 

iwire

Moderator
Staff member
Location
Massachusetts
jute said:
can (2) sets of GFCIs share the same neutral??? Thanks, JB

No.

Your options are a GFCI receptacle at each location you want GFCI protection or a 2 pole GFCI breaker that will provide GFCI protection to all receptacles.
 

jute

Senior Member
Location
SO CAL
iwire said:
No.

Your options are a GFCI receptacle at each location you want GFCI protection or a 2 pole GFCI breaker that will provide GFCI protection to all receptacles.

This is a Square D panel... Assuming Square D sells a 2 pole GFCI breaker... I could run a 12-3 w/ grd, MWBC from a 2 pole GFCI breaker to the first box/receptacle and then alternate circuits so I would have (4) GFCI protected outlets on each circuit without the need of any GFCI receptacles... Is this right???Thanks, JB
 
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Minuteman

Senior Member
Two GFCI circuits cannot share a common neutral, because as soon as there is a difference in the current in the circuits, the GFCI's will trip.

Try using 12-2-2 (aka 12/4) after the first J-box. 12-2-2 has a Black, Red and White and a White w/ Red stripe.
 

cschmid

Senior Member
Now with all the extra costs with the other ways you might as well just run 2 circuits it will be cheaper..as you have wire and GFCI outlets on hand, no trips to supply house no wasted time..much better just little extra copper..
 

jute

Senior Member
Location
SO CAL
Minuteman said:
Two GFCI circuits cannot share a common neutral, because as soon as there is a difference in the current in the circuits, the GFCI's will trip.

I thought that a 2-pole GFCI breaker might let me do this...Is there 2 neutral wires coming off a GFCI 2-pole breaker or one??


Try using 12-2-2 (aka 12/4) after the first J-box. 12-2-2 has a Black, Red and White and a White w/ Red stripe.

I thought about this but not until I had 12/3 running from the first j-box to the last j-box (BOO-HISS)... Any suggestions on how I can alternate these without removing the 12-3 w/ grd currently installed???Thanks, JB
 

cschmid

Senior Member
ahh this is an after the fact question..LOL..I guess a 2 pole GFCI CB would be answer..I would rip the wire and start over skip couple of breaks and walla done correctly..:grin: :D lets see 8 X 11 = 88 yep cheaper to by 2pole GFCI
 

Minuteman

Senior Member
I could be wrong, but I still think the 2Pole GFCI Breaker will trip when there is a difference in the current. I can buy generic GFCI outlets for under 6 bucks.
 

jute

Senior Member
Location
SO CAL
Thanks to all for the info/suggestions...I have a few days to think about this before I go back. Thanks again and have a great day...JB
 

Bob NH

Senior Member
jute said:
Hello.
I have (8) kitchen countertop receptacles in a kitchen remodel... At the time I have 12-3 w/ grnd running from the first j-box to the last j-box. My question is...can I install a MWBC (12-3 w/ grd) from the panel to the first j-box to control (2) sets of GFCI Protected outlets so I can alternate circuits between them.. I need to have GFCI #1, #3, #5, #7 on the first circuit and GFCI #2, #4, #6, #8 on the second circuit fed by a single MWBC...I know I could run a MWBC and alternate receptacles on it but can (2) sets of GFCI's share the same neutral??? Thanks, JB

The general answer is that you can't share a neutral between two ungrounded circuits at any point after that neutral goes through the GFCI device (single pole device) unless both ungrounded circuits go through the GFCI device (two-pole breaker).

If you run the MWBC to the first box where you want to install the receptacles, you can put two GFCI receptacles on the circuit and run 12-2 from the load side of each receptacle to other receptacles in the kitchen, OR, if you put only one GFCI in the first box you can run the other side of the circuit to a GFCI in another box and extend that circuit in the usual way.
 
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