ECN Forum Forums Code Related Discussion NEC & other Code issues MC Cable/ Concrete bsmt. wall

My feeling is that MC is subject to physical damage because of the aluminum casing. It could very easily be damaged. Certainly more subject to damage than EMT or RNC.

FWIW I get MC in aluminum, steel and lightweight steel.

It is not always aluminum.

NM cable is often run down basement walls on a running board so it is a tough sell IMO that MC is more likely to be physically damaged.

Personally I like EMT on minnis in damp basements.

Being the AHJ in my municipality here’s my slant on this one. I don’t have as much of a problem with the MC cable being mounted on a block wall as long as it is a dry location. We all have seen people use MC cable when they punch a hole through a block wall to feed a wall pack and usually it passes as long as it’s a dry location. Where I have a problem is with the physical protection. Surface mounting MC cable on a basement wall in a residential application is just asking for little Billy to come down and see how much damage he can reek on it while he’s playing alone down there. The point I’m trying to make if it’s okay to use it for a laundry circuit then you would also be saying it’s alright to use it for surface mounted wall plugs on a cement block basement wall and this I would have a problem with. Just my two cents worth. Hi George.

The only real issue I see is physical damage and that is a local call that varies widely across the country. Some AHJs see utility and basement areas as damage prone, others don't seem to. I tend to lean toward the "can be damaged" side.

Most MC is listed "wet location" these days.

Someone explain to me why it's not permitted to have aluminum wire in contact with masonry (250.64(A) but it's okay to have an aluminum jacketed MC cable in contact with masonry. Are the chemistry issues the same? It's okay to have copper in contact with masonry. I need to be educated here.

George IMO the difference is it's of less concern to have the armor get some corrosion than it is to have a conductor suffer corrosion.

I have nothing to back that up, it's just a guess.

The question of it being damaged is as Greg said a local call.

In my area almost every basement has NM running down the cellar walls into the panel and will have few NMs running all the way down on running boards to outlets.

This is how its done here, this is what passes inspection and yo know what....it works fine.

I don't see these getting damgaed very often.

Can they be damaged? Sure.

Do they often get damaged? No.

We also use SE for services and if any place little Johnny is going to swing a bat a cable it seems it would be outside.

It's just a local thing, you can bet if it was causing problems it would change.

I guess I'm not concerned about
Johnny's basebaall bat. I was thinking more about the corrosion. Guess I can sleep better now after reading "Uses Permitted" a little closer.