Knob and Tube wiring replacement

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ernie hodgson

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Can anyone give me a reference in the NEC code concerning wether the knob and tube panel must be replaced when replacing the K&T wiring? I inspect weatherized homes which sometimes involves insulation, which can't come in contact with K&T wiring. Thanks
 
Moderator Note: Members, the OP is not an EC but is not asking how to do his own electrical work so we can help him out.

Ernie, the site rules prohibit us from helping you do your own work but we can answer general code questions.
 
There are two distinct parts to the answer; it's really a topic that calls for a professional, on-site opinion.

There are no limitations as to wiring methods and panels. Any recognized wiring method can be used with any panel. The details of the wiring method must be followed.

If you're re-wiring a house, that is almost certain to be a major enough job that modern code requirements will have to be met. This means a complete re-arrangement of the circuits, more circuits, different devices, etc. Only your AHJ can give you the 'right' answer.

If you're responding to restrictions from insurance carrieir, they'll probably want the old fusebox and 60-amp service replaced as well as the K&T.

Finally, if you're thinking of just replacing the sections of K&T that run through the attic, I cannot think of any way for you to do that - and still comply with rules regarding the accessibility of junction boxes, grounding, etc. There's no quick and easy fix.
 
Ernie, welcome to the forum! :)

I'm curious as to what makes the existing panel a knob-and-tube panel, other than it's being existing.
 
ernie hodgson said:
Can anyone give me a reference in the NEC code concerning wether the knob and tube panel must be replaced when replacing the K&T wiring?
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The 1987 National Electrical Code 324-4 Uses Not Permitted for concealed knob and tube is the beginning of the requirement. The history of enforcement by the local Authority Having Jurisdiction will determine your local beginning date for enforcement. Any insulation of Knob and Tube prior to the date of local enforcement of the 1987 NEC is allowed.

A Knob and Tube panel has concealed knob and tube wiring entering it. One is prohibited, by the modern NEC, from placing new insulation in the uninsulated wall cavities, including the panel's location, that contain the concealed knob and tube wiring entering the panel.
 
Knob and tube Panel

Knob and tube Panel

Thanks for all the advice I am trying to give guidance on a simple course of action for multiple agencies who will be insulating homes with knob and tube. As far as the panel being K&T, I am thinking of the older panels wirth edison(?) type glass fuses, I am concerned about combining modern wiring with these older boxes.
 
The new wiring will likely be circuits that require arc fault breakers. So that pretty much forces the use of a new panel. Best thing to do is get the electrical inspector to pay a visit. We can not see what he will.
 
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