New romex to light switch with knob and tube

garym1976

I'm trying to eliminate the last run of K&T from the basement so i can insulate the ceiling. My problem is that i have a hot/live wire k&t going to a light switch . The line goes to the switch then from the switch to the light. I want to run new romex as the live wire to the switch and leave the rest of the knob and tube alone. My question's are is this ok to do and secondly do I just marret the neutral from the romex??
Thanks

AllanJ

If you feed your light with the hot from a new (Romex) cable, you must use the same cable for the light's neutral.

If hot goes into a switch first, the neutral must accompany it. Then hot and neutral continue on to the light.

Admittedly many K&T installations have single conductors running hither and yon. For example hot runs along the exterior wall with branches to receptacles and lights, and neutral runs down the middle of the house accepting the branches from those receptacles and lights. The loose hot and neutral ends left behind when you run a brand new Romex must be taped off and enclosed in accessible outlet boxes or junction boxes until such time as you identify and cut off the other end of any given segment of K&T at which time both ends of that segment may be buried in the wall with no boxes. A loose K&T wire can be taped and curled up inside the box where a new Romex was just strung to replace it. Beware, you may not bury two loose ends in the wall when you are really abandoning a K&T tee with the third end still connected somewhere.

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garym1976

What I forgot to mention is that the hot k&t was already in a juction hooked up to 14-3 from a 70's reno. The junction is loctated in the basement. When I removed the neutral k&t from this wire the light still works. The hot line is going directly in to the light switch. I dont want to change the light or the k&t if I can avoid it. Is it not possible to just run the new romex in to the switch and use the hot and cap the neutral??

AllanJ

In addition, you may not tie together the neutrals from two different circuits (for example one new Romex circuit and one old K&T circuit) in a junction box or outlet box.

Not allowed either.

Neutral must always accompany the hot in the same cable or conduit for each light, receptacle, or other 120 volt load. Exception: the switch loop.

__________________
The disadvantages of crab apple trees. In summer, the apples are too sour to pick and eat. In winter the birds come and leave dropping all over the place.