I understand that:

  • Black wire = hot
  • White wire = neutral
  • Green wire = ground

In the wall switch in my condo, there are 2 switches, one with red/brown wire, the other with yellow/yellow/orange wires. Can someone help explain what these colors mean?

red brown yellow yellow orange

  • What are you trying to accomplish here? Or are you just taking a peek out of curiosity and are confused by the colors? Jun 9, 2016 at 23:36
  • That, and I eventually plan to replace the switch with a dimmer. Jun 9, 2016 at 23:53
  • Why risk it by guessing? Get a multi-meter and be sure. Jul 7, 2019 at 0:12

3 Answers 3


First off -- the only guarantees found in North American electrical code are that neutrals are white or grey (but not all whites are neutral) and grounds are green, green/yellow striped, or bare. Things that are neither ground nor neutral can be any other color -- the reason black, red, and to a lesser extent blue are common is because those colors are what you get with NM cable.

HOWEVER: in a large building like your condo, the wiring will likely be done in conduit instead, which means that you won't find a ground wire (as the conduit subs in for that) and the other wires can be any color whatsoever other than green, white, or grey.

I suspect the yellow wires are hot, by the way, as there are two of them to the same screw on the switch -- that implies that the orange is switched, going off to whatever that switch controls. It's a lot harder to tell on the other switch, but perhaps the red is hot and the brown is switched? Note that a standard single pole dimmer or switch doesn't care which way it is hooked up -- the two brass terminals or black pigtail wires on the switch or dimmer are interchangeable and equivalent.

By the way, when you do put a dimmer in -- it'd be a travesty if you threw a nice, spec-grade switch with wire-clamp plates out in the garbage and put the cheapest builder-grade trash dimmer in in its place. Get a decent spec-grade dimmer from the likes of Lutron, Leviton, or Cooper; it'll stand a good chance of being move-in-ready for whoever you sell your condo to if/when you move out. (The switch is good as a spare, too, if say the next person who moves in hates dimmers, or you need it for something else.)

  • Plus to 3phase but the op may not be here I thought I saw white tracer stripes on the wires not normal unless telecom bundles here every thing else sounds right.
    – Ed Beal
    Jun 10, 2016 at 0:34
  • @EdBeal -- I suspect those are stray paint/mud splatters onto the wires, but it's hard to tell from here. Jun 10, 2016 at 0:48
  • @ThreePhaseEel the dimmer that I intend to get has a green ground screw. If I replace the single-pole switch with the dimmer, how should that be wired (there is no ground in the current single-pole switch, as you can see from the picture above)? Jun 23, 2016 at 17:36
  • @ryanprayogo -- in a conduit install, you'd use a pigtail and green screw into the box (10-32, btw) to connect the ground screw on the dimmer to the box/conduit ground. Jun 23, 2016 at 22:20
  • Or simply allow the ears on the dimmer to be clamped down onto the steel box, which is grounded. Nov 24, 2016 at 6:46

Rejoice in the conduit. It makes modifications easy - for instance if you ever install a smart switch that needs neutral, you can just add a neutral.

You only think of white and black because those are the colors in Romex. Since you're in conduit, that's not a factor. It's a mark of quality for an electrician to use a multitude of colors in an apparent "system". There is no standard for "hot" colors in the US (except, obviously, don't use colors reserved for neutral or ground). The NFPA's mentality is that you should test a wire's voltage rather than relying on colors - think in terms of industrial setups with multiple voltages.

My guess is these colors designate different circuits or breakers, and obviously one is switched and the other unswitched. Dark colors in one group, light in another. You can't know without putting a tester on it, but once you learn the pattern, it'll make further work easier.

  • you mentioned that if I ever install a smart switch that needs a neutral, I can just add it. Well, that time just arrived :) How would this be done? Jul 5, 2017 at 1:35
  • First look in the back of the box for white or gray wire, that's neutral. If no luck, each of the conduits going into a junction box, goes to another junction box. Pop the covers off enough things until you figure out where those switch loop wires are coming from. Then get some white neutral wire and do a conduit pull of that additional wire. First I try everything I can to push the wire through, it works for me 3/4 of the time. Jul 5, 2017 at 3:17

Brown orange yellow signify phase A_B_C from your pole. This is the typical color code for 3 phase. A qualified electrician with a volt meter can tell you what you need to know. If you dont know the significance of these colors your not qualified to work on electricity.

  • That's only a convention for 480Y/277, which will not be found in a dwelling unit context -- even then, an electrician might diverge from it for switch legs, travellers, and such Jul 6, 2019 at 16:29

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