Patching a broken Knob & Tube neutral

[brycenesbitt]

A project I'm working on received a correction notice. Would others comment?

Not pass - at attic: single connections to existing knob&tube wiring must follow 2019
CEC article 394, 300 & 314 as required, wiring must be properly protected and secured
(see pics for current location/condition)- call for reinspection

The situation was: the project added a new subpanel, with the old fuse box turned into a junction box for two remaining old knob & tube circuits running lighting.

Late in the project it became clear something was wrong. Apparently at some point in the past the knob & tube neutral had been severed, and someone (likely not a professional) sponged a neutral from a wildly different subpanel. That lead to a potential double neutral situation of two circuits on the same phase using the same neutral.

Two solutions were considered, and option B was implemented by the electrician on the project:


I was note on site: but the crew tells me the City inspector was concerned seeing the neutrals heading in two directions, out of concern that it was a double neutral.
So now the question is try a different solution, or try to explain this to the inspector?
What do your AHJ's have you do when needing to patch knob and tube (here we generally are allowed to use the old methods on the old wires, including running modern wire through tubes when cleaning up old crap work on knob & tube).

 

[jaggedben]

If it was possible to run the patch neutral from that location, why not sever the K&T hot at that same location, cap off the live end, and run a complete new circuit to connect the downstream K&T at that location?

Also if B was possible I would have done that before doing A. The way it was done there are some legitimate concerns about unbalanced current in different locations, especially if there's a metallic wiring method involved.

Beyond offering that as another solution I have no idea how to help you navigate this. The correction notice itself is completely vague and doesn’t seem to say the same thing as the reported conversation.

 

[brycenesbitt]

If it was possible to run the patch neutral from that location, why not sever the K&T hot at that same location, cap off the live end, and run a complete new circuit to connect the downstream K&T at that location?

That would have worked also, let's call that option C.

Opton C would require a new box in the attic as modern to K&T junctions must be done in a box, where on the fly connections can be done the old school way (wrap wire, solder, tape).

The electrician chose B.

Personally, I'd have done A, using spare tubes from another job, because it seems to channel the spirit of the old wiring the best and be the least confusing for the next person to figure out. Option A is conceptually simpler because we don't really know all the wires go (the connection point is actually a mid point in the disconnected branch of the k&t).

 

[brycenesbitt]

Meaning to say: the optimal place to cut the hot may be nowhere near the necessary place to tie into the neutral.

 

[Fred B]

Personally I go with plan C, remove and put in modern wireing. Seen too many issues caused by other contractors and DIY unaware of the proper installation of K&T, that resulted in fire hazzard and burried faults, including blown-in encapsulating the K&T.
And by time you add all those GFCI for all the ungrounded receptacles, or issues caused by reversal of the L/N at a light fixture creating a hot screw shell on an Edison, just better off rewire. IMO.

 

[tortuga]

The problem is most apprenticeship programs don't teach knob and tube or even a understanding a knob and tube circuit and you can't just go buy the parts you need at the supply house, so unless your a packrat like me, one might not have the proper materials & training to make a k&t repair.
I often see illegal and unsafe knob and tube 'repairs' done by highly reputable companies, such as romex staples used to secure the type R wire or wires just run thru a romex connector without the loom.
So yeah probably option C

 

[mtnelect]

The problem is most apprenticeship programs don't teach knob and tube or even a understanding a knob and tube circuit and you can't just go buy the parts you need at the supply house, so unless your a packrat like me, one might not have the proper materials & training to make a k&t repair.
I often see illegal and unsafe knob and tube 'repairs' done by highly reputable companies, such as romex staples used to secure the type R wire or wires just run thru a romex connector without the loom.
So yeah probably option C

Please let knob & tube die a peaceful death and reduce your liability at the same time.

 

[mtnelect]

Please let knob & tube die a peaceful death and reduce your liability at the same time.

Also, add 25-year-old floor furnaces to that list.

 

[jaggedben]

Please let knob & tube die a peaceful death and reduce your liability at the same time.

Easier said than done. Somebody has to pay to replace it, plus the possible drywall work as well. And the K&T is often in older homes with fancy finishes.

 

[retirede]

Easier said than done. Somebody has to pay to replace it, plus the possible drywall work as well. And the K&T is often in older homes with fancy finishes.

And left undisturbed, isn’t much of a problem.

 

[Buck Parrish]

And left undisturbed, isn’t much of a problem.

That's right, my experiences have been, the problems with KT is when you start adapting to it.

 

[mtnelect]

That's right, my experiences have been, the problems with KT is when you start adapting to it.

Replacing a device is very challenging ... just disturbing the cloth covering, it will disintegrate before your eyes.