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Electrical Wiring and Safety

2011 NEC New Code Rule
Relating to Switch Circuits

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WHILE EXTREME CARE HAS BEEN IMPLEMENTED IN THE PREPARATION OF THIS SELF-HELP DOCUMENT, THE AUTHOR AND/OR PROVIDERS OF THIS DOCUMENT ASSUMES NO RESPONSIBILITY FOR ERRORS OR OMISSIONS, NOR IS ANY LIABILITY ASSUMED FROM THE USE OF THE INFORMATION, CONTAINED IN THIS DOCUMENT, BY THE AUTHOR and / OR PROVIDER.

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The 2011 NEC has added a new rule in regards to switch circuits. NEC is the National Electrical Code which is applicable to the United States.

That new code rule is...

404.2 Switch Connections.

(C) Switches Controlling Lighting. Switches controlling line-to-neutral lighting loads must have a neutral provided at the switch location.

What that means is that at every switch location there must be a grounded conductor (neutral) present regardless if there is a need or not.  Now a lot of us will scratch our heads on this one just as I did when I first heard about it thinking why is there a requirement to have a grounded conductor (neutral) present when the switch circuit does not require one at every switch box.  But as I research this in more detail as to why this would be a requirement, I start to understand the intent of the new rule. Modern times are getting more into the use of timers, and so called green switches / controls that can sense the presence of people and automatically turn off lights or switch them off after a certain time set on the timers. Some users will try to install these devices long after the original circuit was wired. These special devices require a grounded conductor (neutral) present to work. Using the equipment grounding conductor to take the place of a grounded conductor (neutral) is not allowed. However some people are tempted to do just that to enable the device to work.

The other side of the coin is that in a lot of switch circuits some switch locations will not have an 'always on' ungrounded conductor (hot) present which will not allow a timer / smart switch to work anyway. Yet the new NEC rule still requires the grounded conductor (neutral) to be present.

Like a lot of rules exceptions do exist...

The grounded circuit conductor shall be permitted to be omitted from the switch enclosure where either of the following conditions in (1) or (2) apply:

(1) Conductors for switches controlling lighting loads enter the box through a raceway. The raceway shall have sufficient cross-sectional area to accommodate the extension of the grounded circuit conductor of the lighting circuit to the switch location whether or not the conductors in the raceway are required to be increased in size to comply with 310.15(B)(3)(a).

(2) Cable assemblies for switches controlling lighting loads enter the box through a framing cavity that is open at the top or bottom on the same floor level, or through a wall, floor, or ceiling that is unfinished on one side.

Also note that this section seems to contradict code. As NEC 90.1(B) says: This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance results in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.

 Please view the following video that explains the rule...

 

I would really recommend taking the time to watch the above video in full as it does explain the new rule in detail

Please note the NEC (and this new rule) only applies to the United States and this new rule does not apply to Canada (is not in Canadian code yet). However that does not prevent you from wiring your switch circuits to comply with this new NEC rule even if you live in a location where the 2011 NEC does not have jurisdiction and may come in handy in the future having a grounded conductor (neutral) available even if one is not required for the current wiring configuration.

For a switch that is a cut off for a furnace is not controlling a lighting load, and therefore this rule does not apply.

This website is aimed at an international audience with our main audience being the United States and Canada, along with that not all the switch wiring options presented on this website meet this new 2011 NEC 404.2 (c) rule but each switch article will indicate if that wiring option does meet the 2011 NEC 404.2(C), that will be indicated just bellow the 'switch wiring title' but above the disclaimer, as well as in the menus. 

Some switch wiring circuits will now require a 4 wire cable (plus bare) in order to comply with this new rule. On this website those switch wiring options that used a 4 wire cable in order to comply with this new rule has a 4th wire blue in color. From research it seems to have two cable options available that is a 4 wire red / blue / black / white (plus bare) cable and a red / black / white and white with a red strip through it (plus bare). If you get the cable with the 4th wire being the white with a strip through it, use that wire in place of the blue wire indicated in the switch articles, and indicate at both ends of that wire that it is being used as an ungrounded conductor by wrapping a piece of black electrical tape at both ends of the wire on this cable (you could also blue electrical tape).

Now 4 wire cables are available but you may have to look around for it, and I suspect more places will be carrying it as the demand rises due to this new NEC rule.

Written: Jan 26, 2012
Revised: June 9, 2013
By: Donald Kerr

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