MWBC Wiring Questions


Old 11-14-19, 05:49 PM
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MWBC Wiring Questions

Long time lurker, first time poster. Have two MWBC outlets that need minor changes.

First one (MWBC Wall.jpg; has grey background) I would like to remove the receptacle and turn it into a jbox. Is it just a matter of wiring the 12/3 black to the 12/2 GFI circuit black and removing the neutral & ground wires that run from the pigtails to the receptacle?

Second one (GD DW MWBC.jpg; has brown background) is a 12/3 MWBC for a Dishwasher & Garbage Disposal. The 12/3 wire runs below a couple joist bays and need to be moved into joist bays to be out of the way of basement refinishing. I would like to add a second garbage disposal to this GD circuit on an existing bar sink. Relocating the wire into the bays will cause it to be 5 ft short. I can do a jbox but what would be the preferred way wire it from the jbox to the two sinks (1 - gd & dw sink; 2 - gd only sink). Is there any way to wire this for AFCI/GFCI combo receptacle or are new breakers & wire run the only option?

Appreciate it.
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Old 11-15-19, 01:47 PM
Join Date: Mar 2010
Location: USA
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Yes you can remove the receptacle from the box, connect all the blacks together, connect all the whites together, and put a blank cover on the box. Unnecessary pigtails (not needed to extend a wire or connect two wires to one screw, etc) may be omitted.

Ground fault circuit interrupter and arc fault circuit interrupter receptacles can be placed anywhere along the multiwire branch circuit when all the connections are made to the line side terminals and the load side terminals are left empty.

In addition, a 12-2 subcircuit may be run from any of the AFCI or GFCI receptacle load terminals to additional ordinary receptacles or to devices wanting GFCI etc. protection.

It is recommended that if an appliance or device that uses more than half the amperes rating of a branch circuit is left plugged in to a circuit for regular use or is hard wired on that circuit then the circuit should not have receptacles open for general use by other varied devices.

Last edited by AllanJ; 11-15-19 at 02:10 PM.

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