Updating ceiling light fixture with knob and tube wiring

Old 11-25-19, 09:36 AM
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Updating ceiling light fixture with knob and tube wiring

Hello everyone,

I'm trying to update a light fixture in my 1929 house. The walls are made of plaster and lathe, and some of the ceiling lights still have knob and tube wiring. I want to install a new light fixture, but am unsure how to do so with the knob and tube. I've read a few things online that say legally I need to install a new electrical box, but I don't know how to do that with the current setup of the light. Does anyone have any suggestions? Photos can be found in the links below. Any help is greatly appreciated!!

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Last edited by PJmax; 11-25-19 at 11:44 AM. Reason: imported pics from links
Old 11-25-19, 10:11 AM
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I'm not a huge fan of connecting new fixtures to old K&T wiring. Much of it is well past its useful life, the insulation will crack off, getting a box there is tough, and most new fixtures require 90deg wiring since they may produce more heat that will further damage old wiring.

If you do decide to leave the K&T as-is, usually a pancake box is easiest to install to the lathe and allow the wires to pass through the knockouts reasonably safely.

BUT, I would recommend biting the bullet and replacing the wiring with new wiring. Ceiling fixtures are always the hardest since you'll probably end up with a few holes in your ceiling/walls that need patching... but you'll be one step closer to a K&T-free house.
Old 11-25-19, 11:47 AM
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Welcome to the forums.

That looks more like old BX cable. That is VERY hard to work with. Replacing the box sounds like an easy job but it will not be. I'd put that job outside a DIY project. That old insulation will crack when touched.

I've had to work on wiring like that. I'm an experienced electrician and have problems with old wiring.

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