knob and tube wiring

[weatherize01]

I am unclear if we are allowed to remove knob and tube wiring in an attic in order for us to insulate the attic. Can we terminate in a box and run new romex to the existing fixtures or are we required to run a homerun to the box in the basement?

 

[Dennis Alwon]

You may splice K & T wiring into a junction box and you are correct that the K&T needs to be remove before you insulate. Many insurance companies will not give you insurance with K&T so I would remove as much as I can.

 

[weatherize01]

Where in the NEC code can I find that it tells you that you can or cannot splice into Knob and Tube?

 

[weatherize01]

Problem is we have instructors telling our agencies that you may not splice into K&T wiring and that you must run a home run from the panel, in order to do blow insulation in the attic. We always thought you could snip and tap from a junction box in the attic and continue from there? Need to find clear direction in the NEC to put this to rest..

 

[Dennis Alwon]

Right here

300.16 Raceway or Cable to Open or Concealed Wiring.
(A) Box, Conduit Body, or Fitting. A box, conduit body, or terminal fitting having a separately bushed hole for each conductor shall be used wherever a change is made from conduit, electrical metallic tubing, electrical nonmetallic tubing, nonmetallic-sheathed cable, Type AC cable, Type MC cable, or mineral-insulated, metal-sheathed cable and surface raceway wiring to open wiring or to concealed knob-and-tube wiring. A fitting used for this purpose shall contain no taps or splices and shall not be used at luminaire outlets. A conduit body used for this purpose shall contain no taps or splices, unless it complies with 314.16(C)(2).
(B) Bushing. A bushing shall be permitted in lieu of a box or terminal where the conductors emerge from a raceway and enter or terminate at equipment, such as open switchboards, unenclosed control equipment, or similar equipment. The bushing shall be of the insulating type for other than lead-sheathed conductors.

 

[stew]

which code section tells us that k &t cannot be covered by insulation?

 

[krispy fingers]

splicing romex to knob and tube wiring

splicing romex to knob and tube wiring

Weatherize01

Dennis Alwon's post should look familiare, Its the same one we thought applied when we talked this morning

I looked for hours and couldnt find any prohibiting verbiage

 

[al hildenbrand]

which code section tells us that k &t cannot be covered by insulation?

The Concealed Knob and Tube article, Article 394. Read the Uses Not Permitted.

394.12 was changed in the 1987 Code to include envelopment with thermal insulation. Prior to the 1987 NEC there was no such restriction.

Given that the installation of concealed K&T effectively ended by 1950, and, given the large quantity of buildings, wired with K&T that were insulated prior to 1987, IMO, most K&T was legally insulated.

 

[stew]

thanks for the direction.

 

[Dennis Alwon]

which code section tells us that k &t cannot be covered by insulation?

Article 394.12(5)
Edit-- When I replied I did not see the last 2 posts-- seems like they were not there first time but I probably didn't scroll down enough.

 

[al hildenbrand]

Article 394.12(5)
Edit-- When I replied I did not see the last 2 posts-- seems like they were not there first time but I probably didn't scroll down enough.

I had a similar experience. Krispy Finger's post (8:56 PM) wasn't visible to me until after I posted (11:59 PM) my response to Stew.

Some serioous server lag.

 

[al hildenbrand]

Welcome to the Forum, Weatherize01 and Krispy Fingers.

Seems to me the real issue is how to reliably energize the "modified or replaced" branch circuit wiring that replaces the K&T. 2011 NEC 210.12(B) is very different than it was.

If you are under the unmodified 2011 NEC, and, since there are no "outlet branch-circuit type AFCIs" being sold yet, one must install combination type AFCI breakers. Neutral integrity of old K&T installations is usually not good. That means the average AFCI combo breaker, with its ground fault sensitivity, will be a problem (with the exception of the GE MOD 3 combo AFCI).

And, since many legacy K&T circuits are overloaded, just giving in to the NMB homerun seems like an all around win to me.

 

[weatherize01]

Thanks Al, I totally agree with you, a home run is the safest. But,If we are only going to refeed the existing devices that are there now is this really necessary. We are funded through the fed's with very stringent requirements, and someone is always looking at costs. Not having to fish a homerun to the basement, and keeping all the work in the attic can save lots of money. :happyyes:

 

[al hildenbrand]

If we are only going to refeed the existing devices that are there now is this really necessary. . .- Not having to fish a homerun to the basement, and keeping all the work in the attic can save lots of money. :happyyes:

That's the roll of the dice. Will a given structure require less labor to slap an AFCI breaker on the existing K&T branch circuit, or will it be less labor to run a homerun? Each structure will have its own unique solution.

 

[ptonsparky]

Thanks Al, I totally agree with you, a home run is the safest. But,If we are only going to refeed the existing devices that are there now is this really necessary. We are funded through the fed's with very stringent requirements, and someone is always looking at costs. Not having to fish a homerun to the basement, and keeping all the work in the attic can save lots of money. :happyyes:

My brother works for a Weatherization company that gets fed funding. He was attending a meeting where a speaker stressed the importance of being more productive. The next speaker informed them that they had 28 days of required training to get in before the end of the year.:blink:

 

[realolman]

seems like a lot of older houses that would have K and T wiring also have studs that run from the basement to the attic with no firestops or nuthin in them. (there is a specific name for that kind of construction, but I can't remember what it is ) I have been able to drop a piece of chain on a string from the attic and go down into the basement and there it lays on top of the basement wall.

For wiring... it's a good thing.

 

[ptonsparky]

seems like a lot of older houses that would have K and T wiring also have studs that run from the basement to the attic with no firestops or nuthin in them. (there is a specific name for that kind of construction, but I can't remember what it is ) I have been able to drop a piece of chain on a string from the attic and go down into the basement and there it lays on top of the basement wall.

For wiring... it's a good thing.

Open Frame, I think

 

[Riograndeelectric]

seems like a lot of older houses that would have K and T wiring also have studs that run from the basement to the attic with no firestops or nuthin in them. (there is a specific name for that kind of construction, but I can't remember what it is ) I have been able to drop a piece of chain on a string from the attic and go down into the basement and there it lays on top of the basement wall.

For wiring... it's a good thing.

I think it is called balloon framing. my house was built in 1945 a contractor friend of mine called it Balloon framing .

I am sure there are several other names for this type of framing
( back in the days when studs were not dementional lumber. got to love those old pine 2X)

 

[al hildenbrand]

I think it is called balloon framing.

I agree. I've always known it as Balloon Framing.

The outer envelope of the building was framed from sill plate to rafters with un-cut studs, even if the house was a tall ceiling-ed two story. This outer envelope was the "balloon".

Then the floors were put in. Commonly a 1 x 4 was notched into the inside of the balloon 2 x 4s so the floor joist could rest on it, before it was nailed to the 2 x 4 stud. The floors were followed by the interior walls.

The open attic to basement stud bay exists only in the exterior balloon. In my area, with its cold winters, finding those stud bays not filled with insulation is extremely rare.

 

[LEO2854]

seems like a lot of older houses that would have K and T wiring also have studs that run from the basement to the attic with no firestops or nuthin in them. (there is a specific name for that kind of construction, but I can't remember what it is ) I have been able to drop a piece of chain on a string from the attic and go down into the basement and there it lays on top of the basement wall.

For wiring... it's a good thing.

That really helps..:thumbsup:

I have done a lot of jobs where we just remove all the K&T for insulation company's..