Electrical – Power to fixture to switch – How to wire

electrical

I'm working on installing some recessed lighting in my basement and am looking into how to wire it. The way it is now, the power is fed to the current light fixture now and then to the single pole switch all using 14/2 Romex.

I was going to use Romex 14/2 to install the new lights and then continue it to a new LED compatible dimmer switch with the white neutral on the hot side, like I've seen in some diagrams. Upon further investigation, NEC 2011 and newer require switches to have a neutral, so the way it is wired now is not correct and that I need to wire everything from the first light fixture to the switch with 14/3 Romex.

Also, the dimmer switch I have says it doesn't need a neutral unless wiring as a 3-way switch, which I'm not.

I've asked two different people who have done some wiring before and one says to use 14/2 since that is acceptable and the other says 14/3.

Does it really matter which I use or is one more correct than another?

Best Answer

The current Code requires that neutral even if you don't use it

You will need to use 14/3 for the run from the fixture to the switch (called a switch loop in the trade). This is governed by NEC 404.2(C):

(C) Switches Controlling Lighting Loads. The grounded circuit conductor for the controlled lighting circuit shall be installed at the location where switches control lighting loads that are supplied by a grounded general-purpose branch circuit serving bathrooms, hallways, stairways, or rooms suitable for human habitation or occupancy as defined in the applicable building code. Where multiple switch locations control the same lighting load such that the entire floor area of the room or space is visible from the single or combined switch locations, the grounded circuit conductor shall only be required at one location. A grounded conductor shall not be required to be installed at lighting switch locations under any of the following conditions:

(1) Where conductors enter the box enclosing the switch through a raceway, provided that the raceway is large enough for all contained conductors, including a grounded conductor

(2) Where the box enclosing the switch is accessible for the installation of an additional or replacement cable without removing finish materials

(3) Where snap switches with integral enclosures comply with 300.15(E)

(4) Where lighting in the area is controlled by automatic means

(5) Where a switch controls a receptacle load

The grounded conductor shall be extended to any switch location as necessary and shall be connected to switching devices that require line-to-neutral voltage to operate the electronics of the switch in the standby mode and shall meet the requirements of 404.22.

Exception: The connection requirement shall become effective on January 1, 2020. It shall not apply to replacement or retrofit switches installed in locations prior to local adoption of 404.2(C) and where the grounded conductor cannot be extended without removing finish materials. The number of electronic lighting control switches on a branch circuit shall not exceed five, and the number connected to any feeder on the load side of a system or main bonding jumper shall not exceed 25. For the purpose of this exception, a neutral busbar, in compliance with 200.2(B) and to which a main or system bonding jumper is connected shall not be limited as to the number of electronic lighting control switches connected.

Informational Note: The provision for a (future) grounded conductor is to complete a circuit path for electronic lighting control devices.

(Note that in an unfinished basement, point 2 of the above may hold, but I would still run the 14/3 cable anyway -- it's cheaper to do it right now than to fix it later.)

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