Running Electric with Metal Studs

[HereInOhio]

I tried to gather my information before posting but still need to ask.

I framed my basement in metal studs and installed the bushings and NM wiring though the holes. I started installing the outlet boxes (plastic) and wondering two things.

1.) Besides the gourmets securing the wire to the box do you also need to secure the wire to the framing before the box? If so which ones of the many fasteners do you prefer? I'm use to running the wire through wooden studs and just out of habit I always secured the wire within a foot of the boxes so I feel awkward not securing it to the metal studs.

2.) Can you use plastic boxes? I read the issue of them not being grounded. Wondering if I ran a copper grounding wire from the framing to the ground that is connected to the main panel is all that is needed? Or I could just get metal boxes if that's better.

Thanks!

 

[wwhitney]

1) NM always needs securing within 12" of a box that has integral clamps, or 8" for a single gang box with no clamps.

2) The issue of bonding the metal framing is not one I've come across before. Certainly a good idea, probably required. If all the metal framing is screwed together, then a single metal box screwed to the framing would bond everything. Metal boxes have some advantages, so there is something to be said for using all metal boxes.

A few comments on using metal boxes: the EGC in the NM needs to be bonded to the box in a way that does not depend on the presence of a device (receptacle, switch) in the box. Then if you use a self-grounding device, you are allowed to omit the wire type EGC connecting to the device (I'm not making a recommendation either way). 4" square by 2-1/8" deep boxes are nice for lots of room. Then the mud ring depth should be 1/8" greater than the wallboard thickness, with the box set back 1/8" from the face of the studs. That allows room for the heads of the screws holding the mudring on.

Cheers, Wayne

 

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[HereInOhio]

1) NM always needs securing within 12" of a box that has integral clamps, or 8" for a single gang box with no clamps.

2) The issue of bonding the metal framing is not one I've come across before. Certainly a good idea, probably required. If all the metal framing is screwed together, then a single metal box screwed to the framing would bond everything. Metal boxes have some advantages, so there is something to be said for using all metal boxes.

A few comments on using metal boxes: the EGC in the NM needs to be bonded to the box in a way that does not depend on the presence of a device (receptacle, switch) in the box. Then if you use a self-grounding device, you are allowed to omit the wire type EGC connecting to the device (I'm not making a recommendation either way). 4" square by 2-1/8" deep boxes are nice for lots of room. Then the mud ring depth should be 1/8" greater than the wallboard thickness, with the box set back 1/8" from the face of the studs. That allows room for the heads of the screws holding the mud ring on.

Cheers, Wayne

Ok thanks. I think I will just switch out the boxes to the metal ones, believe I saw them referred to as 1900's. I appreciate the info of the mud rings, I read you mentioning this in the thread other thread I found while searching.

As far as securing the wires do you have a preference of fasteners/clips?

 

[wwhitney]

I've not worked with metal studs. Erico Cj6 (aka Colorado Jims) would work fine. Anything that you can secure with a screw instead of a staple or nail. Even a cable tie with a screw eye would suffice.

Cheers, Wayne