ECN Forum Forums Code Related Discussion NEC & other Code issues Multi wire circuits

frodo,

Once a 3 wire Multiwire circuit is divided up into individual circuits there is no problem using a GFCI Receptacle on 1, or both of them.

If you think about it, the service itself coming into the house is a multiwire circuit. There is no problem with GFCIs on individual circuits coming off that.

Bill

We install multiwire circuits in residential projects all the time. How can you say the running two 10-2's is less costly and less time consuming than running one 12-3? Its just the opposite. The material cost for the two 10-2's would cost about 3 times as much as the one 12-3 and the labor would be at least double. As Bill Addiss just said there is no problem installing GFI's on these circuits once there converted back to two 2-wire circuits. For the kitchen counter receptacles run a 12-3 to the first receptacle then from there run two 12-2's from this box to the other receptacles. Connect the black of one of the 12-2's to the red from the 12-3 and connect the white of this 12-2 to the white of the 12-3 with a pigtail. Install a GFI in this box using the black from the 12-3 and the white pigtail for the line and the white and black from the other 12-2 as the load. A second GFI will then be installed in the first box that the 12-2 connected to the red is run to.

Frodo,

Multiwire circuits are used every day. I have never seen a problem with multiwire circuits when installed properly. Of course, you must watch your Box fill, maintain proper grounding and most of all remember that the pigtail on the Grounded conductor is necessary because of 300.13(B)

I would not recommend using #10 wire on standard grade devices.

Bill

[This message has been edited by Bill Addiss (edited 04-15-2002).]

frodo-
I'm not trying to sound like a wiseguy, but I suggest you read the instructions that come with a GFI receptacle. They are very detailed and describe how to avoid the problem you had with using them on a multiwire circuit.