Latest Discussions : Electrical & Lighting


05:49PM | 12/21/02
Member Since: 11/28/02
7 lifetime posts
Hello folks,

My 82 year old house still has lots of knob and tube wiring, which looks to be in excellent shape according to my electrician. He recently upgraded our service to 200 amp (it was still 60)and installed a bunch of new, grounded circuits (the PO were running a washing machine, a dryer etc. mostly on the K+T circuits!) I asked him to give an estimate for replacing it all, and he suggested that not only would it be mostly impossible, but also unnecessary, as long as those circuits are not overloaded. For grounded applications, he's going to install a bunch of new circuits around the house (total bill so far about $3500). Claims that K+T has an undeservedly bad rap, that ours is in excellent shape, and that other types of wiring (first generation sheathed electrical cable and BX, of which we have some also) have been far more truoblesome and dangerous in his experience. However, insurance companies will tell you that houses with K+T are practically doomed to fiery deaths. Who do I believe? I feel like if he can run new circuits all over the house, he should be able to disconnect the K+T and effectively rewire the house, even if the old wire is physically left in place. He claims that he could never get to it all without ripping up some significant amount of plaster.

We'd like to have insulation blown into the walls, but I've heard that it's not wise with functional K+T in place. Who do we believe? Should we talk to another electrican? This one's been great so far, and it's hard to believe that he'd be giving us wrong advice when he could stand to make a serious buck by doing the replacement job.

Sorry for the long post, and thanks for your answers!

Joe Tedesco

04:08AM | 12/22/02
Member Since: 07/27/02
140 lifetime posts
Ask for another opinion, I personally would rewire the place and get rid of the old RUBBER insulation.

Read Article 324 in the 1999 and earlier NEC for some rules related to Knob and Tube.

Electrical Inspector

07:46AM | 12/22/02
Member Since: 09/27/02
73 lifetime posts
K&T was meant to be a free air conductor, not one buried in insulation.

There are consientious insulators whom will refuse jobs on this basis alone....

harold endean

04:31PM | 12/23/02
Member Since: 08/30/02
23 lifetime posts
Another good reason for getting rid of K & T is that there is no grounding conductor. I believe that it would be safer with newer wiring. The K & T wire also has been know to break down in splice boxes over light fixtures. The use of high wattage bulbs in light fixtures tends to make the K & T insulation very brittle, so when you go to change a light fixture, all or most of the insulation falls off leaving bare wires.



10:55AM | 12/24/02
AndyC, That electrician is a keeper, He sounds like a wise electrician and has given some good advice. K & T wiring, as a system is safer than the NM cable we use today! If they would have had made NM cable made out of those materials in the early part of the century, every house would have burned down by now. Likewise if you used today's cables and installed it in K & T fashion you wouldn't be able to afford it!

Should you replace it, YES, you should, eventually the insolation on the wire will fail. Do you need to rush into it, depends on your electrical needs. If your electrician has put new circuits to the high load areas, TV's Bathrooms, laundry, and Kitchen, you should be OK for a while. Watch out for newer light fixtures, they demand 90 degree wire, if you don't replace the circuit, don't change the fixture.

Work with your electrician, he isn't out to empty your wallet, and totally re-wiring an old house is very labor intensive, the best time to re-wire is during remodeling when the walls are opened up.

I would hold off on the insulation until the outside walls have been re-wired.

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