Why are both wires white and black hot at the outlet, and light switch and even at the light in the ceiling

  • 2
    Hello, and welcome to Home Improvement. It isn't clear what you're asking; would you add pictures of the insides of the boxes involved? And, you should probably take our tour so you'll know how best to participate here. Nov 1, 2019 at 20:28
  • What are you using to test the wires for "hotness"? Nov 1, 2019 at 22:57

2 Answers 2


In the case of a light switch, it is normal if the switch is setup as follows:

[elec ]B=========#==============+
[panel]W--------+ +X---------X+ |        
                | |           | |   
                (~)           [-]
               light         switch

The white wire is carrying power back to the light, and convention dictates there should be a piece of black tape (X) around the white wire to indicate it is a live return.

It's important that the switch must go against the live lead not the neutral.

-- Minor edit to diagram. The wire from the panel usually ends in the ceiling. A new wire runs to the switch, black to black with a nut, and white (switched hot) back to the fixture. # indicates this nut.


In all reality, there is no official distinction of what color wire is for what. However, common convention says the black = hot/powered/charged/incoming, white = neutral/return, green = ground/earth, and red = switched.

When it comes to 3/4 way switches, it's not uncommon to see 2 blacks, 2 whites, or each color as hot. Same for switched outlets or outlets running in parallel. If an inexperienced homeowner did any kind of rework, could also explain it.

  • 2
    Green/yellow-green/bare equating to earth/ground is a hard Code requirement. Also, if neutral is present it must be white or gray. White and gray can be reallocated to hots. Nov 1, 2019 at 23:18

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