Thread: Knob & Tube in a Remodeled House

I inspected this house 3 years ago but was reminded of it when I posted about another house with K&T. In this 1920s house the central air-conditioning was retrofitted. The floor cavity between floors was used as the return air duct for a few feet. The pictured K&T wiring is in use with both the hot and neutral wire passing thru the sheet metal caps that were installed at both ends of the return duct.

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Originally Posted by Don Martin

I inspected this house 3 years ago but was reminded of it when I posted about another house with K&T. In this 1920s house the central air-conditioning was retrofitted. The floor cavity between floors was used as the return air duct for a few feet. The pictured K&T wiring is in use with both the hot and neutral wire passing thru the sheet metal caps that were installed at both ends of the return duct.

Not allowed in the return air plenum like that.

When the place was remodeled those should have been removed, and an approved wiring method for return air plenums should have been installed in its place. Contractor either did not know, did not care, or figured it cost too much to change ... or ... of course ... it may have been unpermitted and unlicensed work ...

Originally Posted by Jerry Peck

When the place was remodeled those should have been removed, and an approved wiring method for return air plenums should have been installed in its place.

I completely disagree. You'd re-wire a house because central A/C was installed???

The HVAC contractor created that violation and it is HIS responsibility.
He should have used some other form of return, like maybe duct work.

Originally Posted by Speedy Petey

I completely disagree. You'd re-wire a house because central A/C was installed???

Pete,

First, it would be helpful and consistent with what I said, if you said what I said, not make up your own words which says completely different than what I said.

Originally Posted by Jerry Peck

When the place was remodeled those should have been removed, and an approved wiring method for return air plenums should have been installed in its place. Contractor either did not know, did not care, or figured it cost too much to change ... or ... of course ... it may have been unpermitted and unlicensed work ...

NO WHERE IN THERE DID I SAY "re-wire a house" ... did I?

Nope, I said:

Originally Posted by Jerry Peck

When the place was remodeled those should have been removed, and an approved wiring method for return air plenums should have been installed in its place. Contractor either did not know, did not care, or figured it cost too much to change ... or ... of course ... it may have been unpermitted and unlicensed work ...

That IS A LOT ... A LOT ... different than saying to "re-wire a house", which IS what you said.

The HVAC contractor created that violation and it is HIS responsibility.
He should have used some other form of return, like maybe duct work.

So, you are in agreement with me that "those should have been removed, and an approved wiring method for return air plenums should have been installed in its place" - right?

Again NO WHERE IN THERE DID I SAY 'the electrical contractor is responsible for this because they created the problem' ... did I?

*I* did not say *who* is responsible , *I* only said that it was not allowed and NEEDED TO BE REPLACED - right?

Pete, get the facts straight, don't make up fake quotes.

Wow Jerry. I was NOT "making up fake quotes" or putting words in your mouth. I was simply making a statement. I think anyone here with enough intelligence to be a contractor or HI knows what I meant. We are not dealing with DIY'ers here, are we?

You know as well as I do that K&T wiring circuitry in a home was convoluted and widespread. So to replace some of it would require replacing a LOT of it. True, not the whole house, but quite a bit, especially considering what I see in that pic.

And no, I don't agree that "those should have been removed, and an approved wiring method for return air plenums should have been installed in its place". In this case I think a different duct arrangement should have been made. Unless of course the HVAC contractor made prior arrangements to have the electrical work done at the same time.

And I NEVER said that YOU said anyone was responsible. I said that. I think that was pretty clear.

I have to say, YOU read WAY more into my post than was intended.

Knob & Tube, ( and fuses ), are unfairly villanized IMHO. Installed correcty, it is very safe. NM cables are bundled which allows heat transference where K&T conductors are isolated. The achilles heal is the insulation of the day that can age, crack and break off. Electrical demand keeps increasing which ultimately rendered the 14 gage copper K&T conductors inadequate for much more than lighting. The real danger of wiring in environmental air is the fire potential for poisonous off-gassing. I'd be willing to take my chances w/ a couple K&T wires w/ rubber & cloth insulation in my return air space over today's thermoplastic insulated wires. The scary part in your photos is custom snipped sheet metal around unprotected wires, ( no non-conductive bushing ). Fuses are better protection than C/Bs because they don't mal-function, but the fact they could be defeated w/ the penny
&/or foil thing was their demise.

Originally Posted by Speedy Petey

Wow Jerry. I was NOT "making up fake quotes" or putting words in your mouth. I was simply making a statement. I think anyone here with enough intelligence to be a contractor or HI knows what I meant. We are not dealing with DIY'ers here, are we?

Pete, you posted of quote of mine and then said: "You'd re-wire a house because central A/C was installed???", and I said nothing of the like.

IF someone had read my post, yes, they probably would have (at least should have) realized the difference, except that your statement implied that I said that the house should be re-wired, and I did not say that or anything like that.

And no, I don't agree that "those should have been removed, and an approved wiring method for return air plenums should have been installed in its place". In this case I think a different duct arrangement should have been made. Unless of course the HVAC contractor made prior arrangements to have the electrical work done at the same time.

And if there was no other reasonable route for the return air, and that was why it was routed there? For whatever reasons the return duct was routed there (the "reason" does not matter, the fact that it is there is what matters), those need to be replaced IF left in the duct as they were.

I say "IF left in the duct" because it may also have been possible to configure the return air duct so that the duct left an air space outside the duct in which the knob and tube was left in place, and were not in the duct.

Regardless, as shown in the photo, which is in the return air duct, that knob and tube wiring needs to be removed and either relocated or replaced with a wiring method which is suitable for use in the duct.

And I NEVER said that YOU said anyone was responsible. I said that. I think that was pretty clear.

Definitely not clear to me.

I have to say, YOU read WAY more into my post than was intended.

I may have - my apologies if I did.

Would not have been an issue in New York State.

Of course that's assuming the job was permitted and/or inspected in the first place.

State code indicates that if you encounter Knob and Tube during any installation you shall remove it.

Endeavoring in an area upstate, there are numerous houses with K & T still active.

However, I have personally experienced more fires due to old BX than K & T.

And this is an area of the country where "blown in" insulation surrounds
K & T in most of those houses yet there is minimal problems associated with such.

Why is it that K & T does not overheat in light of all the talk about "bundled" NM?

Amazing that a 100 + year old wiring method is still functional albeit obsolete and inadequate for today's purposes.

Originally Posted by Richard D. Fornataro

And this is an area of the country where "blown in" insulation surrounds K & T in most of those houses yet there is minimal problems associated with such.

Why is it that K & T does not overheat in light of all the talk about "bundled" NM?

Knob and tube DOES overheat in insulation - you just don't see the effects of it ... it's buried in insulation.

Originally Posted by Richard D. Fornataro

State code indicates that if you encounter Knob and Tube during any installation you shall remove it.

Do you have a NYS Resi code section to support this? This is one I have never heard.

Originally Posted by Speedy Petey

Do you have a NYS Resi code section to support this? This is one I have never heard.

Got that from a NYS code update class attended about two years ago.

I am attempting to locate the source of that information which was provided in a handout.

Until I can locate that, I'll retract my statement but I am confident that I was apprised of that at one time.

No problem. Thanks.
in the meantime I'll see what I can dig up.

It's not like we'd extend or add to any K&T, but sometimes we do have to deal with it and leave what's there.

Speedy,

Actually, as of this composition, I cannot locate any information regarding knob & tube wiring in the NYS Code.

Presently we are utilizing the 2010 version and in both Residential and Buidling Code there is no mention of K&T whatsoever.

I believe the 2007 version used to indicate that it must be removed if it was either concealed or in contact with insulation much like the NEC, however, the 2010 version seems to have left that out entirely.

I know that I've been doing this for a while, so maybe it just seemed like recently but I know for a fact that we were told that the state mandated its removal whenever you encountered it in a previous code update class.

Now....I can't even find mention of such a thing as knob and tube.

Seems like there should be something on it.

I'll keep looking.