Knob and Tube

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Re: Knob and Tube

I have not seen a house wired in 1969 using the knob & tube wiring method. I have herd of such a thing. I guess that some areas didn't adopt the NEC and didn't even require an inspection. I worked on a commercial building in AL. that they said was wired by the carpenters in the 1960's. After seeing the way that place was wired nothing will ever surprise me again.
 
Re: Knob and Tube

I guess anythings possible! But I would think knob and tube would not be on the market in 1969.
The houses Ive seen with K and T were wired
(I think)in the early part of the 20th century. BX and NM were available soon after.
 
Re: Knob and Tube

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Wasn't it in 1967 that the code mandated the ground wire in the cable? (reduced ground NM).
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I believe it was before then on the ground wire. My parents house was built in 1962 and all the circuits have a reduced size ground in the NM.
 
Re: Knob and Tube

One of the last houses I worked in that had the reduced-ground in the silver-and-tar sheath, during a remodel, had the ground only as far as bath and kitchen outlets near the sinks, etc.

Beyond those boxes, they transitioned to a non-ground version of the same cable. In other words, the circuits' home runs went to the sink areas first; i.e., lights, switches, recep's, etc.
 
Re: Knob and Tube

The 1962 NEC was the first NEC to require the grounding of all receptacles.

Prior to the enforcement of the '62 NEC, there was a list of specific situations that required grounding that left most general receptacles as two wire ungrounded.
 
Re: Knob and Tube

ju,

Go to Google and type in "Knob & Tube" (without the quotes). Before you hit enter, or click on the Search button, click on Images above what you typed.

Then hit enter, or, click on the button labeled "Search Images".

I got 649 hits when I did it.
 
Re: Knob and Tube

Jim,

Right back at ya!

Sundial Wire looks to be selling porcelain post and tubes for $35 apiece. . .I may just have a new retirement nest egg in those couple boxes of salvage I've gathered over the years.

:D
 
Re: Knob and Tube

:) If this house was near Cadillac, MI, I was involved in wiring of house in knob & tube in about that time frame. I was thinking it was 68 though.

There was quite a controversy over whether it met current code. Final determination was that it did.

Gentleman having it built was familiar with code and swore by knob & tube. He said he had never heard of a fire caused by knob & tube wiring, other than when being extremely overloaded.

He got inspector to agree to it and was willing to pay for job on time and material basis. There is a lot more labor involved.

How many of you have seen residential wiring in rigid conduit. Now that is a real pain in the ???. :)
 
Re: Knob and Tube

Originally posted by dlhoule:
I was involved in wiring of house in knob & tube in about that time
Click to expand...
Fascinating!

Do you recall if the receptacles were grounded? or was it all true to two-wire ungrounded?

If the receptacles were grounded, do you recall how that was done?
 
Re: Knob and Tube

Service came off of pole mounted xmer 240/120.

No ground anywhere.

As far as I know the only problem he had was convincing inspector to allow him to install Knob & Tube in the 1st place.

I might add that knob & tube is much more labor intensive than romex.
 
Re: Knob and Tube

Originally posted by al hildenbrand:
Originally posted by dlhoule:
I was involved in wiring of house in knob & tube in about that time
Click to expand...
Fascinating!

Do you recall if the receptacles were grounded? or was it all true to two-wire ungrounded?

If the receptacles were grounded, do you recall how that was done?
Click to expand...
I have seen grounded knob and tube. I do believe it was a "homeowner" refit. Whoever did it fished a #10 thhn ground to each of the electrical openings and back to the panel. You know, open joints in the attic, etc. I suppose this arrangement would at least provide minimal protection so long as nothing got cut or broken, but seems to me it would have been easier and safer to just rewire in romex.

I am also unsure of the legality of this. I havent researched it, but I am of the opinion that 250.64(B) would be a reasonable application even though it is regarding the grounding electrode conductor. I am also fairly sure that there is a code reference about making joints without an enclosure inside a building.
(If I am wrong about the enclosure thing, please tell me. Boxes cost money .)
 
Re: Knob and Tube

There were absolutely no type of electrical grounds in the building. The tests I did with a meter showed no more than .4 volts to water pipe, gas pipe, and furnace ductwork.
 
Re: Knob and Tube

Originally posted by dlhoule:
Gentleman having it built was familiar with code and swore by knob & tube. He said he had never heard of a fire caused by knob & tube wiring, other than when being extremely overloaded.
Click to expand...
I wonder how many romex fires were started with wiring that was NOT overloaded?

That is such a lame statement by that man. Insulation was not common back then, so the knob and tube system ventilated well.

I would wonder though, if devices were actually built more durably back then.
 
Re: Knob and Tube

Originally posted by Matt Harp:
I havent researched it, but I am of the opinion that 250.64(B) would be a reasonable application even though it is regarding the grounding electrode conductor.
Click to expand...
You can't apply that section to that problem. They perform different functions, they're called different things, it doesn't work.

Why bother, when you have 250.120(B) and 300.3 to throw out there? :D
 
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