Wiring in metal building

[pocketlock]

So, now that my building is built, I’m working on doing my own wiring. I just mounted all my boxes and am planning my runs for my 12/2 MC. I have 3 switch boxes that run between my door and window requiring them to somehow pass by a horizontal support bar (not structural) and one vertical post. I’m certain it will be fine to drill a hole through it to run the wire, but I was wondering if I need some type of bushing to protect the MC (I know it has the metal sleeve on it already but I know code can be picky sometimes). just looking to answer the final few pieces before we starting pulling cable. I included some crude drawings of what I am talking about. I looked around and found some questions similar but no definite answers. I will be sheeting the walls with drywall or plywood in the future.

 

[Sumboodie]

anti-short bushing

 

[eejack]

Nothing is required to protect the mc. Personally I would use good holesaws and file the holes after drilling. Remember to sweep off the metal crumbs from anything that will be overhead ( so you don't get metal in your eyes later ).

When you go to pull the mc notice there appears to be sloped ridges in the cable and it will pull easier in one direction than the other. Make your life easy and plan around that if possible.

 

[pattenp]

There are NEC requirements as to how MC is to be run and supported. NEC 330.15,17.

 

[pocketlock]

anti-short bushing

I will have antishort bushing at the terminations I’m mainly referring to if there was a bushing needed where the metal sleeve will pass through a hole in the tube

 

[pattenp]

I will have antishort bushing at the terminations I’m mainly referring to if there was a bushing needed where the metal sleeve will pass through a hole in the tube

There is no NEC requirement to use a plastic bushing in the punch out of a metal stud so the same goes for MC passing through a metal framing tube unless there is a local requirement.

 

[sparky 1971]

anti-short bushing

Anti shorts go and inside the MC cable

Anti shorts may not be a code requirement, but use them anyway. I've seen more than my share of eff ups that could have been prevented with a $.01 bushing and two seconds of time. Most rolls of MC even come with a few bushings.

 

[pocketlock]

Anti shorts go and inside the MC cable

Anti shorts may not be a code requirement, but use them anyway. I've seen more than my share of eff ups that could have been prevented with a $.01 bushing and two seconds of time. Most rolls of MC even come with a few bushings.

Definitely using them, cheap insurance for sure! Just wanted to make sure the metal sheathing didn’t need a separate bushing when it passed through the metal framing. Looks like it shouldn’t pet the 2 codes an earlier post mentioned.

 

[sparky 1971]

I left out part of my post. You already know there isn't a code requiring a bushing, but pulling MC through holes in metal framing is a *****. The ribbing in the jacket gets stuck really easy. Some sort of bushing makes it a whole lot easier, especially when having to go through more than one hole. If you have any horizontal runs, bushings are a blessing. I listed a couple, they are either for the factory holes or for a hole that is made by a stud punch, but there is nothing that says you couldn't use them after running a hole saw through the framing. Unfortunately, I don't know what size hole is needed, I have a stud punch and just use that.

B-LINE BY EATON Metal Stud Grommet,Universal,Plastic (BM2) | Zoro

Order Eaton B-Line Metal Stud Grommet, Universal, Plastic, BM2 at Zoro.com. Great prices & free shipping on orders over $50 when you sign in or sign up for an account.

www.zoro.com

Greenlee 7/8 In. Metal Stud Punch Bushings - 100 Count

Greenlee 7/8 In. Metal Stud Punch Bushings - 100 Count - 711C

www.acmetools.com

 

[pocketlock]

I left out part of my post. You already know there isn't a code requiring a bushing, but pulling MC through holes in metal framing is a *****. The ribbing in the jacket gets stuck really easy. Some sort of bushing makes it a whole lot easier, especially when having to go through more than one hole. If you have any horizontal runs, bushings are a blessing. I listed a couple, they are either for the factory holes or for a hole that is made by a stud punch, but there is nothing that says you couldn't use them after running a hole saw through the framing. Unfortunately, I don't know what size hole is needed, I have a stud punch and just use that.

B-LINE BY EATON Metal Stud Grommet,Universal,Plastic (BM2) | Zoro

Order Eaton B-Line Metal Stud Grommet, Universal, Plastic, BM2 at Zoro.com. Great prices & free shipping on orders over $50 when you sign in or sign up for an account.

www.zoro.com

Greenlee 7/8 In. Metal Stud Punch Bushings - 100 Count

Greenlee 7/8 In. Metal Stud Punch Bushings - 100 Count - 711C

www.acmetools.com

Thankfully I only have about 7 runs in total, all vertical, and they only have to pull about 3 feet so I’m hoping I’ll be able to deal with it but I’ve seen some of those options! Thanks for the suggestions!

 

[sparky 1971]

Thankfully I only have about 7 runs in total, all vertical, and they only have to pull about 3 feet so I’m hoping I’ll be able to deal with it but I’ve seen some of those options! Thanks for the suggestions!

You will be fine

 

[readhead]

We wire some sheds for customers before delivery. The inspector is okay with either NM or MC for buildings without interior wall finish as long as there are no horizontal runs below eight feet that could be damaged. He cited the code but I couldn’t tell you what it is.
We take the same tact on metal buildings and don’t have any horizontal runs below eight feet. So far the inspectors have been satisfied.

 

[pocketlock]

We wire some sheds for customers before delivery. The inspector is okay with either NM or MC for buildings without interior wall finish as long as there are no horizontal runs below eight feet that could be damaged. He cited the code but I couldn’t tell you what it is.
We take the same tact on metal buildings and don’t have any horizontal runs below eight feet. So far the inspectors have been satisfied.

No real horizontal runs beyond a loop to come into a box from underneath in 1 or 2 spots.

 

[wyliesdiesels]

anti-short bushing

Not required for MC.

 

[wyliesdiesels]

Anti shorts go and inside the MC cable

Anti shorts may not be a code requirement, but use them anyway. I've seen more than my share of eff ups that could have been prevented with a $.01 bushing and two seconds of time. Most rolls of MC even come with a few bushings.

That happens when someone doesnt cut it properly.

Get an MC rotary cutter and you wont have that issue

 

[sparky 1971]

That happens when someone doesnt cut it properly.

Get an MC rotary cutter and you wont have that issue

True. I have a couple of roto splits but I still am going to use bushings. It's just cheap insurance.

 

[Norcal]

True. I have a couple of roto splits but I still am going to use bushings. It's just cheap insurance.

Bought a Klein MC cutter, still prefer the Roto Split.

 

[sparky 1971]

I had a Klein but finally threw a fit and tossed it in the trash the week before last after I took the knob off and put it on the roto split. I actually liked the Klein better when it worked. The problem was it didn't work very often. I was constantly having to adjust the handle because the blade was slipping.

 

[wyliesdiesels]

I have the curved version of the roto-split which forces the wire, inside the MC, down away from the blade, to prevent it from getting cut. works great... i cant find a picture of it online...

 

[dougf]

OP, your building looks great. I have a similar building and its been a shitshow finishing. It looks like your metal studs are at least 4' on center instead of the 5' mine is. Good luck and im sure it will turn out great.

 

[pocketlock]

OP, your building looks great. I have a similar building and its been a shitshow finishing. It looks like your metal studs are at least 4' on center instead of the 5' mine is. Good luck and im sure it will turn out great.

They are like 50” on center. I was told they were going to be 4 foot on center with 3 foot on center on the ends but they ended up evenly spacing them throughout the run. It passed inspection just going to be a slight headache sheeting it later on.

 

[dougf]

yeah, thats going to be a little bit of a pain, but maybe not too bad if you sandwhich the metal studs with a 2x4 and secure your siding to that. This was my plan prior to giving up on that idea due to the headache.

 

[pocketlock]

I think between that and some strategic use of 12’ drywall I’ll make it work I think I’m planning to do unfinished drywall on the lower 8 feet for now and haven’t decided above that.

 

[Toolfool]

I framed out the entire building and hung plywood on all the walls.

 

[pocketlock]

I framed out the entire building and hung plywood on all the walls.

I may do this but set them inside of the wall to keep it from encroaching into my floor space too much.

 

[Toolfool]

I may do this but set them inside of the wall to keep it from encroaching into my floor space too much.

My framing is flush with the steel framing. Being over 30' wide pushed my building into "commercial" design where they double the 2-1/2" x 2-1/2" legs, making them 5" deep. Plenty of room for 2x4 framing and insulation.

 

[pocketlock]

My framing is flush with the steel framing. Being over 30' wide pushed my building into "commercial" design where they double the 2-1/2" x 2-1/2" legs, making them 5" deep. Plenty of room for 2x4 framing and insulation.

Mine unfortunately isn't, but putting a 2x4 in the wall and having it come out 1 inch is better than losing the full 3-1/2" if it were to sit on the floor. Plus it will keep any sheeting off the ground. Sheeting will come much later though. First will be floors, a lift and a loft.

 

[TRWham]

I think between that and some strategic use of 12’ drywall I’ll make it work I think I’m planning to do unfinished drywall on the lower 8 feet for now and haven’t decided above that.

You can get 54” wide drywall (normally used horizontally for walls with 9’ ceilings) or 108” drywall and run it horizontally. I would run the 48”x 108” horizontally.

 

[Toolfool]

Mine unfortunately isn't, but putting a 2x4 in the wall and having it come out 1 inch is better than losing the full 3-1/2" if it were to sit on the floor. Plus it will keep any sheeting off the ground. Sheeting will come much later though. First will be floors, a lift and a loft.

Check around your area, I used to be able to buy 2x3's at my lumberyard back in NY.

 

[acer66]

Check around your area, I used to be able to buy 2x3's at my lumberyard back in NY.

Big box stores normally also carry 2x3’s.

 

[readhead]

Or put hat channels on the wall and screw to that. Cheaper and quick.

 

[pocketlock]

Well I passed my inspection! Thanks for all of the help!