DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Electrical (
-   -   knob and tube question (

marin001 12-20-2008 06:42 PM

knob and tube question
3 Attachment(s)
i have knob and tube and i noticed and read a few of the posts here but i need some advice on the one that i have. if you notice the pics i have attached you will notice that in one pic it is being tapped to a junction box and then it continues to another. i want to remove this knob and tube and would like to know if i cut the wire to one of the junction boxes will that tell me if it feeds the other as this one line that i want to eliminate seems to run only to a switch light and not to the circuit breaker box. also how can i tell which one is hot and neutral as there is a combination of romex, knob and tube, when i followed the knob and tube wiring it seems to go from the light switch i want to disconnect to the first junction box which shows the taps. any help would be greatly appreciated.

InPhase277 12-20-2008 06:53 PM

Your best bet is to get rid of that knob and tube. But to answer your question, you need a multimeter or test light in order to determine which wire is hot. If you have a verified proper receptacle, you can use an extension cord plugged into it. The long slot on the extension cord will be the neutral. If you test from the unknown wire to the neutral on the cord, you will either get a reading, if the wire is hot, or no reading if the wire is dead or neutral.

rgsgww 12-20-2008 07:05 PM

Ehhh...I would just replace that knob and tube. Does that bx (armored cable) have a little silver wire inside of it?

marin001 12-20-2008 10:57 PM


Originally Posted by rgsgww (Post 200707)
Ehhh...I would just replace that knob and tube. Does that bx (armored cable) have a little silver wire inside of it?

i will check to see. i do want to replace the knob and tube, but i just don't know if i remove it if that will effect the rest of the house as the lights, outlets in the living room and upstairs bedroom will be effected. the third pic which shows the second junction box that has bx running to the breaker box i believe is what's giving the knob and tube power. should i just cut one of the wires of the knob and tube to see what happens???? :confused1:

Gigs 12-20-2008 11:06 PM


Originally Posted by marin001 (Post 200799)
should i just cut one of the wires of the knob and tube to see what happens???? :confused1:

You could, if the power is off at the breaker. Since you don't seem to be sure what goes where, you need to use a voltage probe to confirm it's dead before you go cutting that, or you'll ruin a pair of pliers and possibly your day.

As you implied, it's entirely possible that this K+T serves a large portion of your house. Back then only a few circuits served the entire house.

PirateKatz 12-21-2008 08:00 AM

Those pictures pretty much look identical to my crawl space; a combination of knob-and-tube, Bx, and NM of all vintages. I'd like to completely rewire but I have certain concerns that a fairly straightforward job will turn very complicated, very quickly.

handyman78 12-21-2008 11:43 AM

The ideal situation is to replace as much and eventually all the knob/tube that you have. You do need to know the nature of the connections though (black, white, incoming or outgoing). This will take some investigation with a gauge/test light and then I would use some white electrical tape to mark off the neutral wires. Interesting, the hole size used for a new romex style cable 14/2, 12/2 is about the same as one tube! Progress in quality of conductor insulation!

marin001 12-21-2008 03:49 PM

i believe the knob and tube is being feed by the bx cable in the back(3rd pic) if so then at least getting rid of the knob and tube is going to be a little more easier, the only thing i have to figure out is how to feed the first junc box. since today is sunday church first so tomorrow will be a fun day. :thumbup:

All times are GMT -5. The time now is 03:31 PM.

User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.