Knob and tube replacement


Old 11-12-00, 09:27 AM
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If I wanted to replace the knob and tube wiring in the house I live would it just be as simple as pulling 14-2 or 16-2 in place of the knob and tube.
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Old 11-12-00, 01:56 PM
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No. I'm not an electrician, but re-wiring an old home with knob-and-tube wiring usually involves ripping out plaster walls and ceilings enough to properly run the new wiring and boxes.
I'm sure that you should replace the entire electrical panel, as well, if that has not already been done.
Sounds like you need to re-wire your entire home, and have a pro electrican do the work.
Get 3 quotes from different electrical contractors, and CHECK references. Good Luck!
Old 11-12-00, 03:53 PM
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Don't use 16/2 -- it's not good for anything in your house. And if it was me, I wouldn't use any 14/2 either -- the smallest wire I'd use would be 12/2.
Old 11-12-00, 08:16 PM
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Why do you suggest using 12/2? I'm a new do-it-youselfer but was told that since 14/2 can carry up to 15 amps (which is the maximum amount on a circuit)that is the standard for most house wiring?

Old 11-13-00, 07:29 AM
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12/2 is only marginally more expensive than 14/2, and it is a bit harder to pull and connect to devices.

But, 12/2 provides you less voltage drop, allows longer runs, generates less heat, and allows you to upgrade circuits to 20 amp in the future should the need arise or should you wish to add more outlets.

Anybody else got any other advantages to 12 gauge?
Old 11-17-00, 10:17 AM
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I'll toss in my 2 cents. FYI #14 is the minimum allowed for 120 volts and above. I agree with John that #12 should be the smallest you use. When I first bought my current home 6 years ago. I was in college at the time and that marginal difference in cost was very significant at the time and I used it. I have re-rocked walls I ran it in, and either found that my needs for that circuit have increased, or learned of a code requirement that says I should have used #12. Now as a matter of strict policy I will not use #14, even on my 15 amp circuits.

The extra money you spend up front on #12 will turn out to be a big savings if you close up a wall and find out later you need that circuit to be 20 amps.

Old 11-17-00, 04:41 PM
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When I built my present home in 1977, I chose to use 12/2-w/g for all receptacle and lighting circuits. My lighting circuits have 15 amp breakers, and all receptacle circuits have 20 amp breakers.
I have never had to go back and re-wire any of this because of using 12/2 to begin with, and we have added umpteen new electrical loads to our system now with no problems.
Your call.
Good Luck!
Old 11-19-00, 07:49 AM
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All the above replies have very good advice. I agree with what they said.

I will now try to put a few things into perspective to the minimums of the NEC and the life's expectancies involving the construction industry.

By the NEC all general lighting circuits are allowed to be as small as 14 ga. but no smaller conductor is allowed in a dwelling unless low voltage such as door bells with a step down transformer.

All receptacles is the "kitchen, nook, dining, laundry, and bathrooms must be 12 Ga. wiring and 20 rated with 20 amp overcurrent devices. [breakers or fuses].

Specialty circuits such as a welder, range, water heater, etc that pulls more than 15 amps must be sized especially for that special use type circuit. These requirements are found all over the NEC. If questions on a specialty circuit repost a question naming the specialty circuits and any of us will be glad to guide you on that circuit's design.

All wiring in a dwelling is allowed to be 100% rated. No allowances are required for continuous use [3 hours or more] except motors which are sized in article 430 under there own set of rules. The 80% or 125% does apply in a dwelling concerning motors only.

What these guys are trying to protect you from is experience once you are done of lights dimming or breakers kicking due to too much load. The dimming will occur of you lights, if those lights are on a circuit that you plug a hair dryer or motor or electric iron, etc. When these heavy loads are applied to a 14 ga. wire it is common that the lights will dim. This does not imply that there is anything wrong, or anything right when your lights dim due to starting a load, just that this light is starving for electricity because that large load sucked all the electricity when it turned on. Most of the time 12 ga. will limit the experience of dimming of lights or equipment running slow like an iron taking to long to heat up, or a computor going haywire due to low voltage or a surge in the ciruits electricity.

Now as for real life you have to understand that when a builder hires to build a home, or an electrician knows other bids are being competed against him. He will design the wiring to meet just the minimums unless 12 ga. is specified because it they don't bid the minimum such as 14 ga then another electrician or builder would take the job because they did bid lowest by using the minimum design. Kind of like you get what you pay for.

IF it was me I would still get competition bids ensuring the lowest cost but I would specify 12 ga for my own home. Remember that I would not wire my home just meeting the minimum safety standards.

This is why we advise above the NEC on many occasions.

Hope this helps


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