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The National Electrical Code requires that all habitable rooms and bathrooms, have a switch controlled light (210.70(A)(1)). It also allows a switched receptacle to be used, instead of a lighting outlet (210.70(A)(1)EX.1).

Later in the code, it requires a grounded (neutral) conductor at switch locations that control lighting loads. However, it does not require a grounded (neutral) conductor, where the switch controls "a receptacle load".

So if a room uses switch controlled receptacles to meet the switch controlled light requirement, is the grounded (neutral) conductor required at the switch?


Relevant code text

National Electrical Code 2014

Chapter 2 Wiring and Protection

Article 210 Branch Circuits

210.70 Lighting Outlets Required. Lighting outlets shall be installed where specified in 210.70(A), (B), and (C).

(A) Dwelling Units. In dwelling units, lighting outlets shall be installed in accordance with 210.70(A)(1), (A)(2), and (A)(3).

(1) Habitable Rooms. At least one wall switch-controlled lighting outlet shall be installed in every habitable room and bathroom.

Exception No. 1: In other than kitchens and bathrooms, one or more receptacles controlled by a wall switch shall be permitted in lieu of lighting outlets.

Chapter 4 Equipment for General Use

Article 404 Switches

404.2 Switch Connections.

(C) Switches Controlling Lighting Loads. The grounded circuit conductor for the controlled lighting circuit shall be provided at the location where switches control lighting loads that are supplied by a grounded general-purpose branch circuit for other than the following:

(7) Where a switch controls a receptacle load.

  • +1 (But since we are talking about residential wiring, can we add neutral in parentheses for the non-professionals?) – bib May 31 '16 at 12:44
  • @bib Updated the question. – Tester101 May 31 '16 at 12:54
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Code is a guide for localities to establish rules. As such, if a locale adopts the code as is, it will be up to them to enforce their rules. Now we are down to the inspector's decision as to whether you comply.

Since the switched outlet is serving functionally as a luminaire, many inspectors would probably take the view that luminaire switches need a neutral (grounded) conductor. Usually when there are two rules and one is permissive and one is restrictive, the restrictive one will apply (unless the permissive explicitly waives the restrictive).

Further, there are practical reasons to include the neutral at a switch for an outlet. Advanced switches, such as remote control devices or a proximity sensor, usually need a neutral. Obviously, devices that would compromise the outlet if used for purposes other than luminaires should be avoided. You don't want a switched outlet with a dimmer to be accidentally used for a vacuum cleaner.

Bottom line, the local inspector will probably be the last word, but I would include a neutral.

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While there is no rule that says a switched receptacle provided under 210.70(A)(1) Exception 1 must be used for lighting loads -- and the exception in 404.2(C)(7) does not exclude the switched receptacle outlets that are provided under 210.70(A)(1) Exception 1 -- I would consider it good practice to provision a neutral at the switch for a switched receptacle intended for lighting use.

As to dimmers and other such devices that can compromise the operation of non-lighting loads: they are forbidden from controlling that receptacle unless that receptacle rejects standard plugs as per 406.11 -- the Lutron DDTR/HDTR series with mating RP-FDU plugs is an example. (You can get them through your favorite electrical supply house.)

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Easy. You need to provide a neutral for switches controlling lighting loads, 404.2c.

But 210.70A1 requires you provide a switch controlling a light in the room. It doesn't say many, it says one, which means zero lights is not an option. If you are using Exception 1 to use a receptacle for the only light in the room...

... then 404.2c must apply there. There would be nowhere else for it to apply.

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I read that with the same surprise that you do: a grounded conductor (neutral) is not required at a switch that controls a receptacle.

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