Electrical Wiring in the Home/Tracing Wiring From Breaker to First Outlet/Fixture
First, this is a home built in 1922. Still has some, although limited, knob and tube wiring in it. The Breaker Panel is on the main Floor, and the circuit in question is wired with an older 2 conductor wire down into the basement where it is spliced into Knob and Tube wiring. From the splice, the Knob and Tube then runs along and through floor joists until it goes straight up through the floor. This is the first issue and where I run into trouble. I know it powers all the lights and outlets on the second floor (2 bedrooms and a small bathroom). I know this because I checked each and every outlet and light with the breaker on and then off. What I cannot determine, is where, specifically, the knob and tube connects to the circuit on the 2nd floor. I took a look at the wiring on the second floor (removed outlets and looked at the wires) and find the wiring in the walls is Knob and Tube, they are a more recent and satisfactory wire. So, that would seem to mean the Knob and Tube runs from the splice in the basement, to the 2nd floor circuit where it once again is spliced into newer wiring. What I need to do is find how the knob and tube is routed and where the connect (splice) is on the second floor and replace all the knob and tube. Is there a way to do this without having to cut into the plaster and lath walls? They are in perfect condition, and I would hate to have to destroy and cut into these beautiful old walls. Short of finding where it connects, I'm not sure what to do next. I can run a new wire from the breaker to the 2nd floor, but that still leaves me with the problem of where I connect to the circuit. If it were just several outlets in a row, then I could connect at most any point. However, with lights and light switches involved, I’m thinking it matters where I connect the power source for the circuit. Or, I guess, I could split the circuit and have one for outlets and one for lighting. Still, I would need to know or be able to locate the precise place to feed power to the lighting circuit – right?
That isn't how knob and tube worked. You can't do what you are talking about.
Leave it alone or learn to like plastering.
I suggest you look for someone with knob and tube who is doing a major remodel, so you can study how it was installed.
There is some information in the American Electrician's Handbook
Also, do a google search and look in wikipedia
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