Good Day

I am planning a MWBC. At the start of this circuit will be an AFCI Receptacle in a Hallway. This will then Branch to Hallway Lights in one direction, and Dimmer Lights & a second receptacle in the other.

It has been my experience that Dimmer Lights and AFCI receptacles do not mix when the Dimmer Lights are on the Load side of an AFCI. However, I want to have AFCI protection for the second Receptacle.

Rather than running two separate cables, (one Branched off the Line side of the AFCI for the Dimmer lights and one off the Load side for the Second Receptacle) could I run a single 14-3 cable? My intention would be to branch the Black wire off the Line side of the AFCI for the Hot side of the Dimmer Lights, branch the Red wire off the Load Wire for the Hot side of the Second Receptacle, and share the Neutral by pigtailing it onto both the Line and Load side of the AFCI Receptacle.

In short, will this cause problems? Thus far I haven't read anything in my code book or any of the manuals advising against it, but it is also a bit of an unusual idea.

  • I know it's a bad idea for GFCIs because they measure current imbalance, but arcing noise will always stem from the hot, so, in theory, only the hot needs to be monitored... – Hari Ganti Aug 14 '18 at 19:35
  • AFCIs are not GFCIs, and you have to think about them differently. The concept of AFCI+receptacle combo devices is fairly silly, since the lion's share of the purpose of an AFCI to do is protect in-wall wiring. A "receptacle" can't do that. If the circuit requires AFCI due to code, a receptacle is illegal unless it's within 2' of the panel (and I believe connected via EMT). – Harper - Reinstate Monica Aug 14 '18 at 19:36
  • @Harper -- first device in-line and metal-clad (AC, MC, conduit) home run for new work, first device in-line for retrofits – ThreePhaseEel Aug 14 '18 at 22:35
  • What is your rationale for using an AFCI receptacle device here? What make and model is your panel? – ThreePhaseEel Aug 14 '18 at 22:35

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