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I'm upgrading switches in my older (1978) home, putting smart switches in. I have found many "interesting" wiring situations, some I have remedied, some I have just left as-is.

Recently I opened a junction box with a single pole switch, controlling accent lighting above my kitchen cabinets. I was surprised to see a single 12-2 cable feeding the box. The black wire is hot, and the white wire is the load, with the bare ground protecting the switch.

What should be done here? Luckily, I'm able to add a smart dimmer because my brand (Lutron Caseta) doesn't need a neutral.

Is this wiring safe? I believe so. Up to code in Massachusetts? There's got to be a white wire connected to a black or red, somewhere else in the house (I haven't found out where yet) to make this work.

What needs to be done, here? Do I need to label the white wire?

marked as duplicate by isherwood, Machavity, JPhi1618, ThreePhaseEel electrical Feb 28 at 3:08

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  • That's a very common switch wiring scenario (maybe the most common). The question has been asked and answered, as you can see in the Related section at right. – isherwood Feb 27 at 13:49
  • That's a different question - that post deals with tying neutrals together from two different circuits, and three-way switches. I have a romex run to a j-box with no neutral, and it's using a white wire for a load. My question is about electrical code in MA, and wire colors. – Matt Feb 27 at 13:55
  • No, it isn't. You misunderstand. There is no neutral under load in your switch box. Look at the diagram. – isherwood Feb 27 at 13:56
  • FYI, Romex is a brand name, not a thing. We're talking about "cables". – isherwood Feb 27 at 13:58
  • Thank you. I have seen the diagram, and it looks like the white serving the load has a black marker on it. Mine doesn't. So, my question: If the white wire is used in this way, is it required to be labelled,according to MA electrical code? – Matt Feb 27 at 14:00

First, stop by the store and look at all the different combinations of colors you can get 14/2 cable in. There's black/white, and, um, let's see... No, that's it, just black/white.

There's also a rule that says all conductors must be in the same cable or conduit. So if you are using a cable wiring system, you can't run 2 cables for the same leg of a circuit (e.g. to get the colors you want).

So clearly, if you are going to use a cable wiring method...

You are stuck with the colors that come in cable

And you have to accomplish all your wiring in those colors. That said, there are rules about wire colors and cateories of wire.

  • Grounds are always Green, yellow-green or bare, and vice versa. No substitutions.
  • Neutrals can only be white or gray.
  • Hots can be any other color.
  • If a cable doesn't need any neutral wires, its white/gray can be re-marked to be a hot. That is the only remarking allowed. In conduit, use the right colors.
  • Other than that, you can't change a wire's category with marking, unless it's very large feeder.
  • Marking a wire within its category is OK.

There's an answer to this, however: colored tape. To start with, most people have black. But nothing keeps you from getting a $4 five-pack of colored tape, and color-coding each wire to correspond with its function. I'm a big fan of red for switched-hot, blue for "alt" switched-hot, yellow for travelers, etc.

When marking wires, mark both ends of the wire. Otherwise it will get very confusing later.

Recent Code changes

There are several recent Code changes that affect switch loops.

  • In a switch loop without a neutral, white must be the always-hot. That way it is easier to use a non-contact tester to detect that it's not a neutral.
  • A white wire re-tasked to be a hot must now be marked a hot color. Previously, the rule was that the marking was not necessary if the usage was obvious.
  • In cable installations, actual neutral must now be included in the cable, unless the cable can be easily refit. E.G. if you have attic access to the lamp and down the wall to the switch. In conduit, actual neutral is not required because it can be easily fished.

It sounds like your switch loop predates these recent Code changes. That is fine; that means the work is grandfathered. You can update it if you please to.

However, I very strongly urge people not to proceed with home electrical work "armed with only a little Google knowledge". First, you need a well-rounded basic knowledge of electrical, otherwise you will constantly be finding things that are new to you, and that interacts very badly with "judging the last guy to be a moron". For instance, I had to "learn cold" what an MWBC was and why that isn't wrong, and only later did I have enough knowledge to realize 3 hots on an MWBC actually was wrong.

The best place to get well-rounded knowledge is honestly a book on home electrical, and the best place to tire-kick for a good one is the library. Find one you like, devour it. Use Google or us to fill in the details. Just watch out for obsolete books.

  • So the OP's current situation is grandfathered in. It would also be legal if he reversed the conductors (black switched-hot, white always-hot), and put black tape on both ends of the white conductor (because that would be to code). Would it be legal if he just put a red-tape on this end of the white conductor? (Not to code because the white has to be always-hot, and both ends need to be labelled - but it's obviously better than the current situation). ... Or is that another question? – Martin Bonner Feb 27 at 16:59
  • @MartinBonner I would do that if I could mark both ends of the cable, otherwise it'll confuse the next guy. – Harper Feb 27 at 17:01
  • This is great! Thank you @Harper. Especially like the bit about this being grandfathered and updating the color marking of the white is optional. – Matt Feb 27 at 18:10

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