I am wiring a new overhead light fixture in my study. I have done lots of light fixtures before but the wires of the new fixtures I have done in the past have always matched the black and white wires of the ceiling wires.This new fixture has SPT-1 or SPT-2 wire (It just says in the instructions that it is one of the other but I do not see an identification on the actual wire). I understand that this new fixture is 'lamp wire' but I want to double check that I am hooking the right wire up to the hot and neutral wires in the ceiling. Here are the specifics: The new fixture wire is brown with both sides having copper wire. There are no grooves or stripes on either side but one side has writing on it. Am I correct in thinking the side with the writing is the 'hot' wire and should connect to the black wire in the ceiling and the side without writing is the 'neutral' side and should hook to the white wire?enter image description here

  • Does the new fixture come with instructions? Was it acquired new, or used? Is it meant to be permanently mounted? Commented Jan 10, 2018 at 0:30
  • SPT has one conductor that has a rib. The ribbed conductor is neutral or white. The smooth conductor is hot or black.
    – Tyson
    Commented Jan 10, 2018 at 0:37
  • Thanks ThreePhaseEel and Tyson, It is new and has instructions but they are very vague and generic. I now see that there is a very slight groove on one conductor so I will assume that is the neutral. Thanks so much!
    – A Cannon
    Commented Jan 10, 2018 at 1:26

1 Answer 1


I think I would say just the opposite. My thinking is that the wire with the writing on it is identified thus the neutral. You can check it out with a continuity tester or an ohmmeter by checking which wire gets a ring from the metal exterior of the fixture, since most fixtures are bonded between the neutral and the grounding wire.

If this is just a replacement cord you can select any conductor and mark it on both ends with white tape and identify it yourself.

Hope this helps

  • 1
    Alternately assuming the light has a regular edison socket for the bulb, the center contact is always hot, even if the housing is not bonded to neutral. So you could use a continuity tester to identify the hot wire that way. Commented Aug 21, 2018 at 19:28

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