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What's the correct way to wire a multi-control rocker switch (e.g. Leviton 1755) that has three switches on one yoke with a common supply? What wire(s) do I run from the switches to each of the loads? Electricians must use something other than hard-to-find 14/4 NM-B, yes?

I'm installing a bathroom fan/light combo into a circuit with an existing vanity light. My plan is to bring power to the switch first (14/2 NM-B), then to the existing vanity, then to the fan. I can modify this arrangement if there's a compelling reason.

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Typically you'd run 14/2 to the vanity, and 14/3 to the fan/light combo.

In the switch box,

  • Connect all the grounded (neutral) conductors.
  • Connect all the grounding conductors.
  • Connect the ungrounded (hot) conductor from the vanity to the switch.
  • Connect one of the ungrounded (hot) conductors from the light/fan to the switch.
  • Connect the other ungrounded (hot) conductors from the light/fan to the switch.

If you're dead set on running a single cable, you should be able to find 14/4 or 14/2/2 at your local electrical supply shop. The big boxes might actually carry 14/2/2, but I haven't specifically looked for it lately. Just remember if you use 14/2/2, you'll have to mark the repurposed neutral so future electricians know it's used as an ungrounded conductor.

As more and more locations adopt the 2011 version of National Electrical Code, you should start seeing 4 wire cable becoming more common and more widely available.

  • What prevents 14/4 from complying with earlier electrical codes? – ThreePhaseEel Feb 25 '15 at 3:38
  • @ThreePhaseEel Nothing, it would have been compliant if it existed. NEC 2011 introduced requirements for a grounded (neutral) conductor at switch locations, which depending on the installation may require an additional conductor – Tester101 Feb 25 '15 at 3:52

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