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My attic has a ceiling light controlled by two 3 way switches connected with BX 14/3. Source and light wires were old knob & tube now replaced with Romex 14/2.

The duplex outlet is a new addition. The attached diagram is how I thought it could be wired. The duplex and switch 1 will be in one box. Romex 14/2 from source and light and BX will enter the box.

The diagram shows source connected to duplex. Then a short black wire runs from other duplex hot terminal, wire nutted to BX white wire with black tape, to common on switch 2. Load runs from common on switch 1 to light. I didn’t show ground wires to keep diagram simple, but everything will be grounded.

Does this layout meet the NEC? enter image description here

  • Can you replace the BX run? – ThreePhaseEel Jun 3 '17 at 22:47
  • BX would be hard to replace. It runs from the attic ceiling down through the attic floor, then down to the switch in the wall on the 2nd floor near the attic entrance door. It is in good contition so why should it be replaced? – henrylr Jun 4 '17 at 16:38
  • considering this is a 3-way system and neutral is at one of the locations, I'd be OK with you not replacing it (404.2(C) requires neutral at at least some switchboxes, but my understanding is that your case falls under the multi-way switching exception to that section of the Code) – ThreePhaseEel Jun 4 '17 at 16:47
  • Thanks. I'm not an electrician but have done much wiring work in my 114 year old home over the last 34 years. The few times I've had electricians do work I have asked them to look at some of my work and they have always said it meets code. I can't imagine how a neutral could be used between two 3 way switches. The 3 way switches I've seen don't have a neutral terminal and all the diagrams I've seen show only 3 wire cable connecting them. The switches do have ground terminals and in my case they will be grounded. Am I missing something? – henrylr Jun 4 '17 at 17:21
  • You are indeed missing something -- the 404.2(C) requirement was put in place to provide neutrals for advanced switching and dimming devices (think "smart switch"). – ThreePhaseEel Jun 4 '17 at 20:15
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Short answer: Yes, as long as the white wire in your circuit is permanently re-identified as another color besides green. And the joint you are showing is contained in a junction box.

Neutrals are not required at the switch location in non-habitable rooms.

Good luck and be careful!

  • Thanks. The duplex, switch 1 and joint will be in the same junction box. The white wire will have black tape around it at each end. – henrylr Jun 4 '17 at 16:42
  • It looks code compliant but perhaps not best practice - many electricians would not use the redundant terminals on a duplex outlet as part of a circuit, but would use wire nuts with a short pigtail to one of the terminals. That way, a failure within the outlet appliance will not affect the remainder of the circuit. – A. I. Breveleri Jun 4 '17 at 18:55
  • By appliance failure do you mean one that trips the circuit breaker? If so, It seems that either, using the redundant outlet terminals, or using pigtails, would make the light will not work. What am I not understanding? – henrylr Jun 4 '17 at 22:02

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