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#45761 - 12/06/04 06:11 PM Knob and Tube wiring
shortcircuit Offline

Registered: 06/27/04
Posts: 608
Loc: massachusetts
Got a call to replace a couple of lights in a little ole ladys house I went to look at what she wants hung and the place was old, with K&N wiring still.

Am I supposed to upgrade the wiring to the ceiling outlet when hanging new light fixtures??

Not sure if the little ole lady can afford to rewire the house to hang a few new lights??


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#45762 - 12/06/04 06:22 PM Re: Knob and Tube wiring
detubbs Offline

Registered: 11/18/04
Posts: 52
Loc: PA
can't ya just run a new circuit for the light instead of rewiring the whole house??

#45763 - 12/06/04 06:44 PM Re: Knob and Tube wiring
russ m Offline

Registered: 02/22/03
Posts: 165
Loc: Burbank,IL,USA
I don't think you have to rewire to hang the light anymore with knob and tube, than you would if it were wired with the old style bx that does'nt have the ground strip in it. It was code compliant when it was installed and I don't think you are altering it.

#45764 - 12/06/04 06:52 PM Re: Knob and Tube wiring
Electric Ian Offline

Registered: 02/10/04
Posts: 132
Loc: MA, USA
I would think that you could replace the lighting fixtures without having to replace the existing knob and tube wiring based on
In fact, 394.10 allows installation of knob and tube as an extension to an existing circuit.
I don't believe that existing knob and tube in hollow spaces of walls and ceiling constitutes an "imminent danger to occupants". Buried in insulation though - well, that's a differant story.

#45765 - 12/07/04 03:06 AM Re: Knob and Tube wiring
shortcircuit Offline

Registered: 06/27/04
Posts: 608
Loc: massachusetts
Most new lights I've installed say wiring must be rated 90 degrees.

When I've droped an old over bulbed fixture connected to knob and tube in the past...the wires insulation is so dryed out it crumbles and falls off if you move it at all.

Also I've found that most of a floor will be wired on 1 or 2 circuits at if you kill one lighting circuit it may require rewiring many lighting outlets.

Also does'nt article 250 say I must ground the newly installed fixture?

What is your experiance with Knob and Tube???


#45766 - 12/07/04 12:46 PM Re: Knob and Tube wiring
Steve McKinney Offline

Registered: 04/30/04
Posts: 80
Loc: Marion, Illinois
Shortcircuit............If it is accessible from the attic, I try to pull it up and run the K&T into a non-metallic j box. Hopefully you have some "Loom" left to run each wire into the knockouts. The loom is the flex tube over the wire, I have been told. One wire per ko. Then tie in some good stuff to it. As long as you are 8' away from grounded appliances, I believe you will be ok. IMHO


#45767 - 12/07/04 04:17 PM Re: Knob and Tube wiring
earlydean Offline

Registered: 12/22/03
Posts: 749
Loc: Griswold, CT, USA
You should install a cut-in (old-work) J box behind your new fixture. And, both the box and the fixture should be non-metallic, as there is no equipment ground. A nice keyless lampholder wih a clip on shade would fit the bill. But, they do make plastic fixtures that look nice, too.
By the way, they still make and sell loom for covering the conductors of K & T wiring.


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