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My basement was recently wired. Some of the light fixtures only have white wires, nut no black wire. I want to connect new light fixtures that have white and black wire in it, and so am confused where to connect the black wire to ?

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    That sounds a bit strange. Can you take a picture of one of the boxes showing the wires? – manassehkatz-Reinstate Monica Apr 11 at 15:09
  • Can you post photos of the insides of the boxes in question? – ThreePhaseEel Apr 11 at 23:30
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I would think, most likely, the installer ran out of black wire strangely enough. In which case he should of put black tape on whichever wire was hot.

You can figure out which is the hot wire (which fyi should usually be black in color) by taking a voltmeter and measuring between one of the whites and the ground wire.

You should get no voltage or very little when measuring neutral to ground.

But you should get 120v when measuring hot to ground. So whichever of the white wires gives you 120v when measuring it against the ground is your hot wire.

Get some black tape, and put a little onto that wire to signify that its the hot, and then attach your light with the black wire going to this wire, and the white wire to the leftover white wire in the box.

  • Doubtful -- this is far more likely to be an old-style switch loop using white for the switched hot. – ThreePhaseEel Apr 11 at 23:30
  • True, I may have assumed he was wiring up a light in a box that was left in the ceiling with the intentions of being used for a future light. I assume it must be emt being run from box to box, as he would have 2 romex runs with 2 black wires if it was indeed romex, In which case if it is EMT a double white could be just an electrician running out of Black wire and forgetting to label his hot. – Christopher Ortiz Apr 12 at 0:11
  • Otherwise, why would you run two wires to a box and (i assume) not have them tied together or at least have another set of wires in there and one of the two tied to a third wire. Two random switched hots , two hots, or even two neutrals in one box, with no other mentioned wires that are not connected to anything wouldn't really make any sense that I could see. This is assuming we are basing this off the logic that it was "recently" wired, as stated by the OP, and not some old disconnected box. – Christopher Ortiz Apr 12 at 0:24
  • I will add this comment to here since I cannot comment on the original post. Op if you are reading this, I am wondering if we are misinterpreting your post. It does say "Some of the light fixtures only have white wires, nut no black wire. I want to connect new light fixtures that have white and black wires in it. We keep asking for pictures of the electrical box, I am curious if you had some older fixtures or something that didnt bother with color coding the wires, I dont think incandescent bulbs care about polarity and may reflect this in the fixture's wiring color code – Christopher Ortiz Apr 12 at 0:28
  • The pictures give us much more insight into what's going on -- it's very easy to disregard things going on in the back of the box as irrelevant when they actually are relevant to figuring out what's happening here – ThreePhaseEel Apr 12 at 4:09
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The light fixtures are probably using lamp cordage internal to the lamp. This stuff is often "all the same color".

Neutral is the ribbed side. Look at the sides of the wire, one will be smooth, one will have a bump or ridges. The ridged one is neutral. The smooth one is hot, mark it with some black electrical tape.

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