Another call for electricians

[Hawkmoon]

New question:

Friends of my wife recently suffered a house fire. The house isn't totaled, but there was significant damage to a couple of rooms -- to the point that much of the main floor has to be gutted to the studs and will be rebuilt from the studs out, after any burned wood has been replaced and the rest sealed to kill the smell of smoke.

The house was built in the early to mid-1950s. Wiring is BX cable (metal armored, as opposed to Romex, for those not old enough to remember BX). My guess is that, from that era, the individual conductors are probably insulated with fabric rather than plastic. The husband asked me if I know how to test the wiring in the areas subjected to the highest heat to determine if it's still safe, or if the insulation has been compromised. I don't know -- and a review of the building code doesn't offer any guidance. I know from experience that just the heat of a couple of light bulbs in a ceiling fixture over a period of years basically "cooks" that old fabric insulation, so I have some concerns about its condition after exposure to a fire. But I don't know of any requirement to test it, nor do I have any idea how it might be tested.

Any guidance from the pros?

[never_retreat]

You would need a tool called a megger. It puts a high voltage low amperage charge on the wire to set it.
You would test between each pair of wires and each wire and the jacket. Also you would have to unhook all the devices to tell if the cable is bad. Chances are that old stuff will never pass even if it was not chard.
Rip it out and replace it.

[Hawkmoon]

Rip it out and replace it.

That's what I told him but for some reason they need to keep the cost of repairs as low as possible.

[never_retreat]

The tool will cost you at least 500 bucks to do this.
You can put in new romex and boxes in a few rooms for that price.
This is really strange because I think the code will make you replace that old stuff because of the fire.
I would not want it in my walls, kind of like buying a car that was in a flood. Nothing good can ever come from it.

[Hawkmoon]

The tool will cost you at least 500 bucks to do this.
You can put in new romex and boxes in a few rooms for that price.
This is really strange because I think the code will make you replace that old stuff because of the fire.
I would not want it in my walls, kind of like buying a car that was in a flood. Nothing good can ever come from it.

I wouldn't want it in my walls, either. Although, given that the house was built with BX and only a portion was exposed to the heat, I'd probably opt to replace the suspect wiring with more BX. In fact, I think that building code requires that. I'd need to look up the exact language, but the general sense is that repairs are allowed using "like" materials.

But I spent a considerable time perusing both the IRC and the IEBC and I could not find anything that suggested a requirement to replace wiring that was exposed to heat but not visibly damaged, nor could I find anything requiring that it be tested, or even giving the building inspector the authority to ask that it be tested. And given that the previous building inspector in our friends' town is currently in prison for accepting bribes and the current inspector was the deputy, I think he's interested in matters other than a small ranch house that was built 50+ years ago.

[zxcvbob]

Can you abandon the old wiring in place and run new Romex?

[Hawkmoon]

Can you abandon the old wiring in place and run new Romex?

The electric code is very clear that abandoned wiring must be removed. That said, what's the point of leaving it? The walls are stripped down to the studs, so there's nothing preventing removal of the old BX. Just pop the staples (I'd guess back then they used 'U' nails) and yank it out.

[zxcvbob]

The electric code is very clear that abandoned wiring must be removed. That said, what's the point of leaving it? The walls are stripped down to the studs, so there's nothing preventing removal of the old BX. Just pop the staples (I'd guess back then they used 'U' nails) and yank it out.

That must be a fairly recent addition to the code.  But if the walls are open and the old wiring is accessible, yeah rip it out.

[280plus]

much easier to ripit out and replace now while everything else is going on. Later on it could start acting up and then what would you do? Rip all the walls apart again? Tell them it's cheap insurance.  or sometimes a penny saved now equals ten pennies later to fix the part where you cheaped out.

[never_retreat]

That must be a fairly recent addition to the code.  But if the walls are open and the old wiring is accessible, yeah rip it out.

You technically leave it in the walls if all the ends of the wires are in proper boxes, caped off with wire nuts and blank covers. This of course has to be exposed, you can't bury them in the walls.
So what you would have would be a bunch of blank plates all over the place.

[Hawkmoon]

You technically leave it in the walls if all the ends of the wires are in proper boxes, caped off with wire nuts and blank covers.

Technically, if you do that you are in violation of the National Electric Code.

The following is from Mike Holt's web site, which specializes in electrical code issues: http://www.mikeholt.com/mojonewsarchive/NECQ-HTML/HTML/NEC_Questions003~20030324.htm

Q4. Abandoned cable is a big problem in my plant. Where in the NEC does is specify that abandoned cables must be removed?

A4. Abandoned cable is identified as a cable that is not terminated at equipment and not identified for future use with a tag [725.2, 760.2, 770.2, 800.2, and 820.2] and the NEC does require the accessible portion of abandoned to be removed [725.3(B), 760.3(B), 770.3(A), 800.52(B), and 820.3(A)]

Obviously, if the sheetrock is stripped off the walls down to the studs, ALL of it is accessible.