Using knob and tube wiring???

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  #1  
Old 09-14-07, 04:47 AM
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Using knob and tube wiring???

Whats the scoop on this. I have never screwed around with knob and tube, nor do I plan on it, but I was curious. What if you wanted to add an outlet or move a light on a second floor that is wired in knob and tube with no feasable way of fishing a romex line from the panel? The nec gives clear guidlines about knob and tube. Kinda seams like if you could somehow get the wires used for knob and tube and solder every connection, using two prong outlets...it would be acceptable. I am just curious on this topic. Again, i wouldn't touch knob and tube wiring, as I believe its usually very safe if you don't start moving it around.
 
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Old 09-14-07, 05:51 AM
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You are not allowed to add new receptacles or extend a circuit that is not grounded. Since knob and tube is not grounded, you can't add to it. Some will argue that you could extend the knob and tube and add a ground wire. My rebuttal is that if you can add a ground wire, you can run a new circuit.

While there are ways to attach to and repair knob and tube, these are usually considered to be outside the scope of do-it-yourself, and best left to someone with experience in the area.

There is always a way of running cables from the panel. It is never not feasible. Sometimes it is not desirable, and it often requires at least some wall or ceiling holes and subsequent repair, but it is always possible.
 
  #3  
Old 09-14-07, 07:11 AM
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My standard advice for people with K&T homes is to not make any changes at all to their K&T electrical system, but begin saving their money for a complete replacement. It could be done all at once, or it could be done one circuit at a time. Often, it's better to start by replacing the panel with one with lots of extra spaces. Then add new circuits one at a time, leaving existing K&T circuits alone. Eventually you can remove and abandon the K&T, but that can wait. Of course, if you are scheduling any sort of other remodel that will be removing the wall surfaces, that's a good time to update the electrical too.

I know that more outlets would be convenient, but I recommend you live without them until you can install a new circuit. Just don't overload the existing circuits in the meantime (i.e., forgo that tanning bed).
 
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Old 09-14-07, 07:12 AM
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As the owner of an 86-yo house, I am amazed at the skill the original electrican used in installing the K&T. He was able to power an entire house off two circuits that look a little thicker than 12-awg. He ran porch lights, three way lights, baseboard receptacles, etc, all while using the width of the physical cavities to separate hot from neutral. From what I can tell, this system has survived all previous owners and has mostly met the needs of the house. Can't say that about the original heat (coal) or plumbing (lead pipe)

That said. I've been tinkering with electric for three years now, and I have nowhere near the skillset the original electrician had. So I decommision his wires and run new. But I am impressed.
 
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Old 09-14-07, 04:31 PM
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Knob & Tube

Fubar... 86 yrs ago, what were the appliances? A few lights,radio.... All the walls were open. From what I've seen, I think the devices went in then the plaster.


John: I could'nt agree more. Don't touch it work around it.
The dilema with the panel change first, Is(in MA. anyway) Now those old 2 wire ckts need to change to GFCI (no grounds), Bedrooms to AFCI.

So now it is a stand off.

Racraft; Correct aswell

"Some will argue that you could extend the knob and tube and add a ground wire. My rebuttal is that if you can add a ground wire, you can run a new circuit."

Adding a ground.. Not recommended, Compliant... arguable.

If you try you can add, sometimes the older houses are easier to snake/fish than the new ones. But thats a whole other thread.

My advice, ignor it and start new.
 
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Old 09-14-07, 04:39 PM
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How about 140 year old house with the same k&t, that has seen all kinds of remodels and electrical splicing with Romex through the years? And finding wires run for lights out on porches that go through sawdust and/or are rubbing up against metal soffit panning, with no electrical box? (need "eek" smiley face) Yet the house still stands.

In life there are a lot of accidents waiting to happen that just don't. But they do happen and we must be vigilant and cure any ills we may find to cover our bases. I'm sure there were plenty misfortunes that DID happen, but we just didn't hear about it because we didn't have the population and media coverage we do today.
 
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Old 09-14-07, 05:09 PM
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Wink Old!!!

How about a house, (my Dads) 1780s', Redone in the 1970s', (by him), I'm still fixing things. And I didn't get any training untill 1980. I'm amazed every couple of months on how far the industry has come, And how lucky the five of us were (are).
 
  #8  
Old 09-15-07, 07:53 AM
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What about when you see a house that has a tiny bit of knob and tube still operating a few two prong receptacles, but in the basement, there is a nice new panel with all romex coming out of it. Does this mean that the electrician somewhere spliced the romex to the knob and tube? Thats not too proffesional
 
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Old 09-15-07, 09:30 AM
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perspective

Originally Posted by strider380 View Post
What about when you see a house that has a tiny bit of knob and tube still operating a few two prong receptacles, but in the basement, there is a nice new panel with all romex coming out of it. Does this mean that the electrician somewhere spliced the romex to the knob and tube? Thats not too proffesional

This all depends on many factors.

The date of the upgrade and the manner in wich the transitions were made.

Alot of the "old" upgrades were made with armored cable from the "new" panel to the first K&T termination. Then the next upgrade the armored cable was replaced with NM cable to that junction.
So as a blanket statement to say it is bad, May not be true at all.

The answers given have been based on the 2005 NEC.

The 70s were QUITE different.
 
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