BX sheathing reuse to house THHN

[Fred B]

I have a residential job with a highly finished ceiling that has a bad and VERY old BX powering a light fixture. Question is "IF" old wire can be pulled out of the BX, can I reuse the sheathing and pull in new THHN to provide power for light fixture and not damage the ceiling? Any NEC requirement that would prohibit this?

 

[infinity]

Short answer no. Type AC cable is a cable assembly that as the conductors installed during the manufacturing process. The sheath is not listed to be used as a raceway so the sheath would need to be listed as FMC to be used as you've described.

 

[Fred B]

Short answer no. Type AC cable is a cable assembly that as the conductors installed during the manufacturing process. The sheath is not listed to be used as a raceway so the sheath would need to be listed as FMC to be used as you've described.

What was BX listed as

 

[ActionDave]

Cable assembly.

Besides not being a listed conduit it's smaller than half inch which is the smallest diameter allowed by the NEC. Even if that was not an issue you would not have any luck pulling the existing conductors out. It's impossible, they just break. I know because I have tried.

 

[infinity]

What was BX listed as

Type AC cable, Article 320.

 

[Eddie702]

Unless by chance it's really 3/8 FMC but then the size would still be an issue

 

[LarryFine]

If there's any paper filler, it's a cable, not a conduit.

 

[Fred B]

If there's any paper filler, it's a cable, not a conduit.

This one has no paper, 2 cloth wrapped conductors, installation size equivalent to modern10-8 AWG with a 14AWG actual internal wire.

 

[winnie]

I've encountered very old BX with cloth and rubber insulation, where the conductors were over wrapped with cloth, where the conductors could be easily pulled out. The overall diameter was larger than modern BX as well.

Doesn't really change that the sheath is not suitable for new conductors.

Jon

 

[infinity]

The ironic part of this question is that if you could pull out the old conductors and replace them with THHN the wiring would be much safer than leaving the old junk.

 

[winnie]

One other point: where I've encountered similarly really old BX, it was often fished into walls rather than new construction. Bit is very likely that this old cable could simply be pulled out while pulling in a complete new cable.

Also, note that cable assemblies are installed in a different fashion than raceways. You can have lots of bends in a cable assembly but not in a raceway.

Jon