I'm trying to replace an interior light fixture. It is a single switch going to the light. The light switch has a yellow and black wire, the ceiling box has a yellow and tan wire and a black wire that is completely sealed off and wasn't used in the existing fixture. Both wires seemed to test hot with a multimeter.

I'm pretty certain the yellow on the switch and the yellow in the ceiling are the same wire. The tan ceiling wire is smooth and the yellow wire is rough.

My question is how should I match the new light wires to the existing wires? How do I tell which is hot and neutral?

Black (new fixture) to Tan (ceiling) and White (new fixture) to Yellow (Ceiling)
OR
Black (new fixture) to Yellow (ceiling) and White (new fixture) to Tan (Ceiling)

I plan on attaching the fixture ground wire to the green screw supplied.







Thanks for any help!

 

It's not tan. It is "aged" white. White to the white of the fixture. Yellow to the black of the fixture.

 

Thanks for your help and a quick response. So is it safe to assume that in this 1950 house, most of the "hot" wires will be yellow? I seem to remember that being the case with one of my outdoor fixtures where the yellow was hot.

 

By code hot wire can be any color but white, gray or green. Black is usually constant hot in a metal conduit system. Yellow or red is usually a switched hot but that is just standard wiring convention not a rule.