MC or NM for exterior masonry wall?

Redline77

I am replacing some old ungrounded circuits on a 20A breaker. Two of the runs go from the basement, up through the exterior masonry wall about 10" to a floor outlet on the first floor.

Currently, the old ungrounded wire is MC, but most of the house is, so i dont know if they used it because they had to or because thats what the rest of the house was. my question is, should this be MC where it goes through the basement ceiling into the exterior wall, or will 12-2 NM be allowed?

Andy in ATL

My interpretation of the code is that you can use nm-b(romex). Any one else?

Stubbie

If your in Chicago or anywhere that has their codes you can't use nm, other wise I agree with Andy.

EDIT: NEC 334.10(b)(2) allows nm inside masonry block walls

Stubbie

Redline77

ahh, thanks guys, I wasnt having any luck sifting through the NEC codes.

For anyone interested in the particulars;

334.10 (A) Type NM. Type NM cable shall be permitted for both exposed and concealed work in normally dry locations. It shall be permissible to install or fish Type NM Cable in air voids in masonry block or tile walls where such walls are not exposed or subject to excessive moisture or dampness.

Stubbie

Yep you got the correct code, Personnally I would use UF in that small of a guage or some NMC if you can find it...probably have to go to a professsional electrical supply. If you think it has any chance of getting excessively damp inside that block I would not use nm-b which is meant for normally dry locations.

Stubbie

Redline77

welp, i went to go pull the old MC out of the wall and....it will not budge.

I disconnected the outlet it was attached to, and looked for any lockrings or MC connectors to the metal outlet box...nothing....so i head into the basement, and grab on to the 8' section, put some weight on it....nothing....not even an inch.

The outlet is about 5" off of the floor, and from the basement, i can see the subfloor, so that means im trying to pull through maybe 7" of MC....

I can see where it goes into the cinderblock from the basement...theres no way they would have wired the outlets *before* they finished building the walls would they?

do i have any options? I put some serious torque on it, and not an inch....although the MC started to stretch at the joints.....arghh.

J. V.

When they laid the block they always get lots of mud in the wall. It's stuck and you may not be able to pull it out.
Looks like you may have to run a new one. Hopefully you can find an open cavity.

Redline77

hrm, thats bad news.

there is a joist about 2" from the wall running parallel, so i dont see how i could get any angle on a drill to put a new hole in, and there are no existing holes other than the one currently occupied by the MC.

what is the *correct* way to replace this if I were an electrician....open up the wall? I have the mudding ability, i just really dont want to....

should i just leave it as non-grounded MC and call it good, or is it a better idea to just do it right while im replacing all of the other circuits