Electricians? Knob and Tube wiring?
Wednesday, May 6th, 2009 at
1:54 pm
the beet asked:
We own a pretty old house, half of which is still wired with knob and tube (not that I really know what that means). How dangerous is it? What do I look for in terms of it becoming dangerous. And lastly, what’s a guesstimate of what it would cost to rewire…it’s an 1100 sq foot house, half already re-wired.
Tagged with: Guesstimate • Knob And Tube • Knob And Tube Wiring
Filed under: Maintenance & Repairs
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sussex electrician
Well Knob n Tubing is OLD, safe but old, Knob n Tubing is an Open conductor running thru Knobs and Tubes, Tubes where they run thru wood, and the Knobs are used for turning corners and such, Its Very Dangerous if you don’t know what you are looking for or at, I personally know someone whom almost got killed from it, Knob n Tubing is reliable as far as use IF theres nothing wrong with it now, But as Far as replacing it in Part of a 2000sq foot home might run you between 3,000$ and 5,000$, That would be bring it up to Current codes, adding outlet if needed and adding a Smoke detector system.
sussex electrical
Ray D is right, but I would want to clarify things… It’s likely not as much of a problem if it is only your lighting. It can get ugly if there are outlets tied into it.
I would make a budget priority of rewiring all outlets away from K&T. Then do your lighting as your budget permits.
Under load this suspended wire scheme is designed to emit heat when the wires get warm. No problem in the empty cavity as designed. But then people start insulating, you don’t want to cover K&T. Plus, if it were to get wet, it can more easily start a fire with any bare spot in the wires insulation in wet fiberglass. (New wiring is double insulated with its outer jacket and ineer sleeve on each power conductor).
sussex electrician
Both of the previous answerers are right on. One addition is that K&T wiring is NOT grounded. There is a hot, and a neutral only. New wiring is designed to take stray voltage to ground, as a protection to the user.
I had K&T in the house I am living in now. It was built in 1868. I replaced all of the K&T wiring almost immediately.
The problem you are going to run into with estimating cost, is that you are remodeling. This costs much more that new construction.
Call in a number of electricians and get a quote to replace the wiring. Let them all know you are only accepting bids at this time and you will be contacting other companies.
Good luck!
brighton electrical
I also live in a 100 + year old house and approx. half the basement wiring is still the old knob & tube. However, all my wires running thru the tubes and the knobs has an insulation coating still on it. I’ve handled some of it occasionally when changing some of the circuits over to alleviate overcrowding of junction boxes and have had no problems with it. I feel it’s perfectly safe, as long as it’s not overloaded, but then that goes for most all wiring anyway. As for the estimate of a rewiring job, you’d be smart to call in a licensed electrician to give that to you. It will depend on a lot of factors and they don’t usually charge for an estimate.
sussex electrical
Answers above are correct as for what it is here is a visual; next time you are outside look up at a telephone pole. You see the wires stretched from pole to pole? The insulators the wire hangs from are the knobs. Tubes are insulators used when passing through something like a wall. This type of wiring is OLD and usually has cloth insulation over plastic or rubber. I have worked on many jobs with this type of wiring and have NEVER seen one yet that did not have brittle insulation that would fall off with little effort. I **** IT!!! It is an electrician’s nightmare.
brighton electrics
If you have to get an electrical permit, you may have to replace exposed K&T. there is a good reason for that. most people with K&T need to have a new service installed with the proper size circuit breakers. the old K&T should not be on more than a 15 amp fuse, but is probably on a 30 amp fuse. be sure it is on a 15.
brighton electrical
Catsco has the most correct answer, it should not be protected at more than 15 amps!!!!! I would get estimates and get it replaced.
brighton electric
i too have a house that is half and half. you won’t have any problems as long as you do not over load the circuits and use only 15 amp fuses. hopefully the fuse panels for both the old and new wiring are well labeled and clear. the previous owners have most likely updated the kitchen and bath(s). do not insulate around any knob and tube wires, and do not run over sized light bulbs in ceiling fixtures. if your house is old style framing, (balloon framing), it should be fairly simple for an electrician to snake new wires for additional outlets and lighting. with balloon framing, the studs in the walls run from the foundation plates up to the attic. that’s why when an old house catches fire in the basement the attic burns, too. do not add to any old knob and tube circuits, the wiring might not be able to handle the increased load. if you do any work on your electrical, you will need to become familiar with testing equipment and the testing of the circuits. also, i use white and red electrical tape to identify the hot and neutral wires in my circuits. i know that black is the correct color for the hot lead, but black tape is the most commonly used and everywhere in the wiring. as long as you keep the correct fuses in the fuse box and do not run too many appliances on it, knob and tube is fairly safe. that said, your insurance company might charge you a higher rate because you have it in your home and are still using it. well, i hope that this has been of some help, i know a bit about what i am telling you as three of the houses that i have lived in have been wired with at least some knob and tube wiring. good luck with your new home.