# Knob & Tube question...



## Frasbee (Apr 7, 2008)

Sure, why not.


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## oldtimer (Jun 10, 2010)

burndy said:


> I have a Knob & tube Question maybe someone can help me with. I would like to know if it is permissible to replace the exposed portion (attic) of the circuit with nm cable. My thought was to find the feed, box it and run new to all the accessible locations. I don't have much experiance with the stuff. Any help would be appreciated.
> 
> I M O I would think, NO. Check with your Electrical Inspector!
> 
> Joe Tedesco will be able to advise you, or maybe The Electrical Guru.


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## Frasbee (Apr 7, 2008)

Wait, what about everything in the walls?


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## burndy (Jul 15, 2010)

Frasbee said:


> Wait, what about everything in the walls?


 I was thinking, box were it enters attic, connected with new nm


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## thegoldenboy (Aug 15, 2010)

Is there insulation in the walls? 

Nothing in Art. 394 that outright prohibits it. Let's look a little deeper.

Are you replacing just the stuff in the attic because it's in contact with insulation? 

Knob and Tube is perfectly fine until there's insulation present. [394.12(5)]

Are you updating the the devices or leaving them as the old ungrounded type? 

Also if you're using metal boxes make sure to bring both the ungrounded and grounded conductors through the same knockout, with the proper bushing of course.

I know we can't extend two wire circuits anymore, however I'm not totally sure this qualifies as an extension or just a replacement. 

For any of the MA guys, if we were to run into this situation I think it would fall under Rule #3 which is how we would be able to get away with it.


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## Sparky3 (Nov 21, 2010)

burndy said:


> I was thinking, box were it enters attic, connected with new nm


Run a new feed from the panel and eliminate the existing knob and tube.


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## burndy (Jul 15, 2010)

thegoldenboy said:


> Is there insulation in the walls?
> 
> Nothing in Art. 394 that outright prohibits it. Let's look a little deeper.
> 
> ...


 The homeowner just asked to have the visiable k&t gone. All existing devices would stay the same, walls are not insulated, the attic is insulated (that old gray stuff) also planned on plastic boxes.


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## MDShunk (Jan 7, 2007)

Yes, and I'd say this is a very common "repair". Insurance companies are demanding that all EXPOSED K&T be removed. Sometimes it's easier to rewire the whole circiut, but other times it's just as you say; box it and replace what's exposed with romex. Finding federal bushings can be a special treat, so I tend to use those blue or black pop-in knockout bushings. You still need to relocate a knob within a reasonable distance of the new box to support the old conductor, and scare up some loom to sleeve it through the federal bushing.


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## Dennis Alwon (May 9, 2009)

I just run the loom into a plastic nail on box. The trick, as Marc stated, is to put an insulator nearby. It is a good idea to take some of the insulators when you replace K&T and save them for future use.


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## burndy (Jul 15, 2010)

Thanks for all the replies. you've all been very helpful.


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## BIGRED (Jan 22, 2007)

MDShunk said:


> Yes, and I'd say this is a very common "repair". Insurance companies are demanding that all EXPOSED K&T be removed. Sometimes it's easier to rewire the whole circiut, but other times it's just as you say; box it and replace what's exposed with romex. Finding federal bushings can be a special treat, so I tend to use those blue or black pop-in knockout bushings. You still need to relocate a knob within a reasonable distance of the new box to support the old conductor, and scare up some loom to sleeve it through the federal bushing.


What is a federal bushing?


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## RIVETER (Sep 26, 2009)

burndy said:


> I have a Knob & tube Question maybe someone can help me with. I would like to know if it is permissible to replace the exposed portion (attic) of the circuit with nm cable. My thought was to find the feed, box it and run new to all the accessible locations. I don't have much experiance with the stuff. Any help would be appreciated.


If it is permissible to connect the exposed portion, what would be the criteria? How close would your junction box have to be to where it disappears? How would you show anyone else working on it in the future that it was not EGC protected?


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## thegoldenboy (Aug 15, 2010)

BIGRED said:


> What is a federal bushing?












Federal bushings.


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## oldtimer (Jun 10, 2010)

thegoldenboy said:


> Federal bushings.


 Older ones were made of porcelain. I think I still have a few.:laughing::laughing:


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## thegoldenboy (Aug 15, 2010)

oldtimer said:


> Older ones were made of porcelain. I think I still have a few.:laughing::laughing:


Actually the website that I got the picture off of said those were porcelain, they still make them. Don't date yourself. :thumbup:


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## ratrod56 (Jan 21, 2011)

I changed a kitchen fixture at an old k&t house. There werent any hots at the switch. I turned switch off and opened old fixture and rechecked for power. :001_huh: Holy smokes everything was still hot with my ticker. But you cant really trust those voltage testers. anyways they switched the noodle instead of hot. First time I ever saw it like that.


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## RIVETER (Sep 26, 2009)

ratrod56 said:


> I changed a kitchen fixture at an old k&t house. There werent any hots at the switch. I turned switch off and opened old fixture and rechecked for power. :001_huh: Holy smokes everything was still hot with my ticker. But you cant really trust those voltage testers. anyways they switched the noodle instead of hot. First time I ever saw it like that.


That's the way it was done then. They also fused the neutrals which actually was safer.


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## doubleoh7 (Dec 5, 2009)

burndy said:


> I have a Knob & tube Question maybe someone can help me with. I would like to know if it is permissible to replace the exposed portion (attic) of the circuit with nm cable. My thought was to find the feed, box it and run new to all the accessible locations. I don't have much experiance with the stuff. Any help would be appreciated.


 

Just rewire the whole thing and be done with it. You will not be in compliance with the NEC if you have it buried in insulation at the top of every wall where it iis spliced. Just do it right and be done with it.


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## jefft110 (Jul 7, 2010)

doubleoh7 said:


> Just rewire the whole thing and be done with it. You will not be in compliance with the NEC if you have it buried in insulation at the top of every wall where it iis spliced. Just do it right and be done with it.


I agree. Here they make you replace all the exposed k&t in the attics and crawl spaces when you do a service upgrade. 

I won't do it. If I touch it, I replace the whole circuit. If the HO doesn't want to pay for it, fine, let the next guy do the upgrade and be liable for the k&t that enters the top and bottom plates.


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## doubleoh7 (Dec 5, 2009)

jefft110 said:


> I agree. Here they make you replace all the exposed k&t in the attics and crawl spaces when you do a service upgrade.
> 
> I won't do it. If I touch it, I replace the whole circuit. If the HO doesn't want to pay for it, fine, let the next guy do the upgrade and be liable for the k&t that enters the top and bottom plates.


 
The homeowner is not spending their money wisely by paying for piecemeal repairs. I see part of my job as to select the most cost effective method to deal with their homes electrical problems. By "most cost effective" I mean that my work will last for 80 or more years just like their K&T did, probably longer.

I don't loose sleep at night thinking about piecemeal jobs coming back to bite me in the ass.


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## electricmanscott (Feb 11, 2010)

doubleoh7 said:


> Just rewire the whole thing and be done with it. You will not be in compliance with the NEC if you have it buried in insulation at the top of every wall where it iis spliced. Just do it right and be done with it.


Not practical or realistic.


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## doubleoh7 (Dec 5, 2009)

electricmanscott said:


> Not practical or realistic.


 
It certainly is. Not only realistic, but it is the right thing to do. You are not thiknking about the exposed K&T on the top plate where you have to splice. K&T is not supposed to be buried under insulation.


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## MDShunk (Jan 7, 2007)

doubleoh7 said:


> It certainly is. Not only realistic, but it is the right thing to do. You are not thiknking about the exposed K&T on the top plate where you have to splice. K&T is not supposed to be buried under insulation.


I'm selling whatever it is that they're buying. 

Naturally, any good businessman is going to try to upsell more work, but if it comes down to it, I'm perfectly happy to do whatever portion they want done. I can do it safely, legally, efficiently, and profitably. 

Not everyone that walks on to a car lot wants, needs, or can afford a Cadillac. Some people just need the Malibu. What if the salesman was to say, "Sorry, I only sell the Cadillacs today. The Cadillac is much safer than the Malibu, and I can't bring myself to sell you the Malibu. Besides, you'll have a much more comfortable ride in the Cadillac, and I'll sleep better at night knowing I will only sell you the safest car in the dealership's lineup". Pretty silly, huh?


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## electricalcj (Feb 9, 2011)

burndy said:


> I have a Knob & tube Question maybe someone can help me with. I would like to know if it is permissible to replace the exposed portion (attic) of the circuit with nm cable. My thought was to find the feed, box it and run new to all the accessible locations. I don't have much experiance with the stuff. Any help would be appreciated.


 
Yes. Once u enter the box, keep in separate holes.


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## thegoldenboy (Aug 15, 2010)

electricalcj said:


> Yes. Once u enter the box, keep in separate holes.


I would like you to explain that one to me, I've always been told to bring them into the same KO or remove material between the KO's if it's a metal box to prevent inductive reactance. I think it's inductive reactance, it's been some time since I've discussed this topic in any great depth. So please, enlighten me.


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## hooch (Sep 18, 2010)

what is the code on service upgrade and k&t?$$$


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## nrp3 (Jan 24, 2009)

I thought it was the same hole in metal or you were supposed to put a slot between the two holes. Go plastic, then it doesn't matter, nail or plastic four square, no bonding either.


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## thegoldenboy (Aug 15, 2010)

hooch said:


> what is the code on service upgrade and k&t?$$$


It would have to be a local thing, nothing in the NEC says you have to update the wiring methods when changing or upgrading the service equipment. Actually in MA we have rules in place protecting us from "rogue" inspectors who may want to enforce something as silly as that.

527 CMR 12.00 

Rule 3: 

Additions or modifications to an existing installation shall be made in accordance with this Code without bringing the remaining part of the installation into compliance with the requirements of this Code. The installation shall not create a violation of this Code, nor shall it increase the magnitude of an existing violation.


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## tquick79 (Apr 30, 2011)

If your gonna do it, do it right......just run a new feed from the main or sub panel and be done with it. Once you get the new feed going just eliminate the circuit that the k&t in on and then tear it out if you want, it's that simple....that's what I would do, then you know it safe and done right!!!!


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## captkirk (Nov 21, 2007)

Oh man Ive made some real good money on Knob and tube removal jobs...


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## nitro71 (Sep 17, 2009)

What this thread has deteriorated to is whether or not to do this type of job. Just replacing the knob and tube in an attic. I'm gonna pass on that that joy of job unless the money is really good. I fail to see why exposed knob and tube is dangerous but what's in the wall isn't. I also feel that disturbing knob and tube creates more problems than it solves.


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## tquick79 (Apr 30, 2011)

nitro71 said:


> What this thread has deteriorated to is whether or not to do this type of job. Just replacing the knob and tube in an attic. I'm gonna pass on that that joy of job unless the money is really good. I fail to see why exposed knob and tube is dangerous but what's in the wall isn't. I also feel that disturbing knob and tube creates more problems than it solves.


That's why he should just bypass it with a complete new circuit. In my opinion it's the only way to do it. It could be labor intensive but it's just the right way to do it.


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## captkirk (Nov 21, 2007)

nitro71 said:


> What this thread has deteriorated to is whether or not to do this type of job. Just replacing the knob and tube in an attic. I'm gonna pass on that that joy of job unless the money is really good. I fail to see why exposed knob and tube is dangerous but what's in the wall isn't. I also feel that disturbing knob and tube creates more problems than it solves.


 totally agree. either get rid of it or leave it alone...If your doing work in a home that has it in some sections and they dont want to remove it ,dont bother it. Just run a new circuit and call it a day. I have seen so many problems with people messing with it.


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## HARRY304E (Sep 15, 2010)

captkirk said:


> totally agree. either get rid of it or leave it alone...If your doing work in a home that has it in some sections and they dont want to remove it ,dont bother it. Just run a new circuit and call it a day. I have seen so many problems with people messing with it.


Get rid of all of it..:thumbup:


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## 76nemo (Aug 13, 2008)

tquick79 said:


> If your gonna do it, do it right......just run a new feed from the main or sub panel and be done with it. Once you get the new feed going just eliminate the circuit that the k&t in on and then tear it out if you want, it's that simple....that's what I would do, then you know it safe and done right!!!!


 
K&T is extremely deadly. That wiring method can literally cause tornados and deep water flooding. K&T can proove Jesus a po*n star and Mary Magdeline a sl*t.

By the sake of Christ, report anyone who still has K&T in a household


Yeah, Ozzy is the antichrist, smash all your stereos:surrender:


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## crazymurph (Aug 19, 2009)

doubleoh7 said:


> The homeowner is not spending their money wisely by paying for piecemeal repairs. I see part of my job as to select the most cost effective method to deal with their homes electrical problems. By "most cost effective" I mean that my work will last for 80 or more years just like their K&T did, probably longer.
> 
> I don't loose sleep at night thinking about piecemeal jobs coming back to bite me in the ass.


 One of your best statements I have read. As much of the old K&T needs to go, it has seen it's time.


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## HARRY304E (Sep 15, 2010)

:thumbup:


crazymurph said:


> One of your best statements I have read. As much of the old K&T needs to go, it has seen it's time.


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