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A recent comment on this question said that it was not unusual to see the grounded leg of a switched circuit being used as the switched leg, there was some agreement.

This seems a terrifying problem if true.

For me, this was learned in the first week of working in the trade.

I could never have passed a rough-in inspection for something like this the day after a hurricane, of a latrine, at a campground in Florida, where he was so drunk someone else had to drive the golf cart.

Does this really happen often?


I removed my answer that spoke of NEC 404.2(B) due to comments by a user that did not think that a citation of, what is law, in some jurisdictions, was relevent to the question. The argument could be made that this perspective is/was reasonable.

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    I think you mean the neutral leg, which is distinct from the ground (even though neutral and ground and bonded at the service panel, they are still distinct circuits and are not interchangeable) – Johnny Apr 1 '15 at 18:46
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    Distinct from the ground - true. This is about the - Grounded Leg - I am speaking of the neutral, as they are bonded at 1 point in the circuit. – Some Guy Apr 1 '15 at 18:49
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    Maybe you misinterpreted what I meant in my comment that you are referring to. I was simply saying that a white wire doesn't always mean neutral, and a black wire doesn't always mean hot. A red wire can be neutral or hot too. It's just the color of the insulation. Ideally the person would mark it appropriately but there is nothing requiring it. – Steven Apr 1 '15 at 19:06
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    NEC 404.2B says that switches shouldn't switch the neutral. It doesn't say that they can't switch a hot wire that just happens to be a white wire. – Steven Apr 1 '15 at 19:08
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    @Johnny, don't have the time to read all those comments but SomeGuy is correct in his terminology. A neutral is "the" ground-ed not ground-ing wire which is the "ground" (green/bare) wire. They are distinct but not in the way you suggest. – ChiefTwoPencils Apr 2 '15 at 4:15
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Not all grounded conductors are white, and not all white conductors are grounded conductors.

There's no problem using a white or gray wire as an ungrounded conductor, as long as the conductor is permanently reidentified.

National Electrical Code 2014

Chapter 2 Wiring and Protection

Article 200 Use and Identification of Grounded Conductors

200.7 Use of Insulation of a White or Gray Color or with Three Continuous White Stripes.

(C) Circuits of 50 Volts or More. The use of insulation that is white or gray or that has three continuous white or gray stripes for other than a grounded conductor for circuits of 50 volts or more shall be permitted only as in (1) and (2).

(1) If part of a cable assembly that has the insulation permanently reidentified to indicate its use as an ungrounded conductor by marking tape, painting, or other effective means at its termination and at each location where the conductor is visible and accessible. Identification shall encircle the insulation and shall be a color other than white, gray, or green. If used for single-pole, 3-way or 4-way switch loops, the reidentified conductor with white or gray insulation or three continuous white or gray stripes shall be used only for the supply to the switch, but not as a return conductor from the switch to the outlet.

There is a problem with switching the grounded conductor, but no problem switching a white conductor (as long as it's reidentified).

Chapter 4 Equipment for General Use

Article 404 Switches

404.2 Switch Connections.

(B) Grounded Conductors. Switches or circuit breakers shall not disconnect the grounded conductor of a circuit.

Exception: A switch or circuit breaker shall be permitted to disconnect a grounded circuit conductor where all circuit conductors are disconnected simultaneously, or where the device is arranged so that the grounded conductor cannot be disconnected until all the ungrounded conductors of the circuit have been disconnected.

Before the introduction of 404.2(C), two wire switch loops were common. Since a two wire cable only has a black and white wire (and ground sometimes), the white wire had to be reidentified and used as an ungrounded conductor.

  • Sidenote: 404.2(C) is the neutral-in-the-switch-box clause that was added recently to support timers, motion sensors, and other "smart" devices – ThreePhaseEel Apr 1 '15 at 22:13
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A switch should always switch the hot conductor (NEC 404.2(B) that you referenced), so I'll assume you're talking about the side of the switch that is not electrified when the switch is off.

In a lot of cases, an electrician won't have an option in the matter, they will use the conductors available. Lets say you have a switch that does not have the line coming into it the box (comes in at the ceiling fixture, for example), but rather its just a 14/2 cable from the ceiling box to the switch box (I know the most recent code requires a 14/3 so there is a dedicated neutral, but that's another story). In this case, they have a switch, and a cable with a black, white and bare conductor. The white conductor is going to have to be used to complete the circuit.

In the best case, the electrician would wrap black electrical tape around the white wire on both sides so you know it is hot, but there's still nothing wrong with using the white colored wire for this.

Some dimmer switches I've bought have white, black and blue wires on them. Again, it doesn't mean anything, it's just a way to identify which wire is which on the schematic. If I drive around my neighborhood, all the transformers have 3 black wires coming off of them. Some of them have white tape wrapped on them, some of them don't. No linesman is going to just assume its one or the other by looking at it.

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