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Electrical Wiring in the Home/install ceiling fan / old house wiring


We decided to purchase a ceiling fan/light to replace an existing 5-bulb light fixture.  When I removed the old light fixture, I found wiring I had never seen before. (our house is a little over 100 years old) There are 2 separate black wires. Each wire runs along the inside of two separate joists and there is a small, round, white insulator every 2 or 3 feet. If I can go ahead and use the existing wire to install the ceiling fan, how do I tell which black wire is hot and which is neutral?


You have knob and tube wiring.  They really didn't separate hot from neutral.  There may be some testers, including Christmas light testers that can tell the difference. (Don't touch any bare metal with the Christmas light tester). It will light near the hot wire, but not the neutral wire. Or you can just connect the wires to either one.
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Electrical Wiring in the Home

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Bob Sponaugle


Just about any home wiring question. (not appliance repair) I have done all kinds of home wiring for myself, including adding a new breaker box, etc. Please, questions from North America only. Please be specific with details.

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