Need to put a light switch to a hot wired light?

I want to change a pull chain light to a switch. Only 2 wires both black(old house) but know the white one, need to know guage type and path for hot wire.(hot to switch, back to light etc..)
Need to put a light switch to a hot wired light?
I don't know your local codes concerning allowable wiring methods such as romex, conduit, or MC. Or the code articles that will apply according to where the fixture is located. So I will be generic here. Take the hot wire off the light fixture, wire nut that wire to the white of a #14 black/white cable assembly. Connect the black of that cable to the screw you just took the old black off. Run those 2 wires to the switch and connect them to the 2 screws on the switch. This is called a switch leg so it is legal and proper to use the white as a hot wire. Connect the ground wire to the switch and to the fixture box.



Do not switch the neutral wire as the other guy told you. You must switch the hot wire.
Need to put a light switch to a hot wired light?
Assuming this is a standard porcelain pull chain light fixture.....

There should be a brass colored screw and a silver colored screw on the fixture. The white or neutral lead should be connected to the silver screw. Remove the black or hot lead from the Brass colored screw, and tie a black wire to it and run it to one side of the switch. Run another wire from the other side of the switch back to the brass screw on the light fixture. The wires should be in conduit or you can use BX cable or ROMEX to + from the switch -depending what the codes are for your area. Where I live, it would have to be conduity. . #14 wire should be sufficient for just a light fixture.
14 ga. is fine for the light. You want to switch the black wire. White stays on the light. Cut black and put the two ends on the switch. It doesn't matter which screw. You have to make your wires longer, which i'm sure you know. If you can't tell which is black or white, either wire will switch the light.