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Question:

Which is the hot wire in nob and tube wiring?

Both wires are black. One has what looks like white paint on it.

Answer:

In Knob and Tube wiring system the black is the hot wire. KT is no longer an approved wiring since the insulation will deteriorate over the years and no ground wire is present. It should be completely removed as soon as possible. The wire with the white paint is probably the neutral wire. To verify this, take a conductor from the neutral buss of the panel and run it to the outlet, then use a solenoid tester to read the voltage.
Sep 26, 2017
Get a basic induction type tester tester. There is no theoretical live and neutral in knob and tube wiring. Wires were put where ever. Switches were put on either wire etc. The same type and color wire is used by both live and common.The only way to tell is to test.
Sep 26, 2017
correct.....both can be hot, as they may have been cris crossed from point to point. the best is to get a volt meter and test to your water pipe if its grounded and not eroded away over the years. problem with using an inductance tester is it may give an erroneous reading if they have been cris crossed. note.....once you find the hot of the two, the other bing the neitral will have a current on it that can be fatal, remember there is no ground to protect you, and if your in water or touching something metallic, you may be the ground path needed to complete the circuit. be careful!
Sep 26, 2017

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