sub panel mount

[HeloMech]

I'm having a sub panel installed in my metal building. The only task I have in the meter is to mount the box where I want it. The frame is 5ft on center, all metal framing. What is the best way to mount the panel? Pictures please..

 

[Charles (in GA)]

I'm having a sub panel installed in my metal building. The only task I have in the meter is to mount the box where I want it. The frame is 5ft on center, all metal framing. What is the best way to mount the panel? Pictures please..

Had to do some searching to find pics of the interior of your steel building. Basically there are three kinds, traditional steel buildings using red oxide epoxy primered C channel, Z purlins and depending on size, welded up "red iron" structure., all bolted together. The second is the corrugated building, no structure at all, the steel and 6 inch deep corrugations give it the strength, usually a "Quonset hut" design, but there are variations with straight walls, and lastly, what you have, which is a evolution of what was originally the "carolina carport" or some other similar brand, the common characteristic being the 2x2 galvanized steel tubing it is made from...................

Long intro, but getting to the point, I would use a couple of pieces of unistrut mounted horizontal between or across two uprights of the building struture. Mount the panel to these pieces and you have a good solid mount. Use galvanize unistrut® or superstrut®, and you have something that matches the structure and won't easily rust. The gold colored material is cad plated and it tends to rust much easier. The galvanize version is available at either Lowes or Home Depot, I forget which.

Do you plan on insulating the building, if so, how? and do you plan on skinning the interior of the building, if so, with what? It will make a huge difference in how you mount the electrical panel. How is the power to enter, thru the wall from outside, via a disconnect or a conduit ell ?

How will you wire the inside, using metal conduit, or PVC conduit, or ???

Won't do any good to show pics of my panel mounting, I have a different kind of steel building, and a different situation.

Charles

For the benefit of others, here is a pic of Helomech's building interior so you can get an idea of the structure and how one could mount a panel.

 

[HeloMech]

Kind of shocked me when I opened the post and my shop came up. Thank you by the way.

I don't plan on insulating or skinning the interior walls. If I were to do so, I'd use bat insulation and no clue on the skin. Shiny corrugated tin if I could afford it later.

I'll use pvc conduit. The line is entering the building from outside through conduit.

I think I know the unistrut material you mentioned. Not sure the best way to mount that and still look good.

 

[Steevo]

You'll pretty much have to screw the unistrut running horizontally to the face of two adjacent uprights.
Use two sticks, one for the top of panel and one for the bottom, and use the shallow (1"?) strut.

http://www.homedepot.com/h_d1/N-5yc1vZbm55/h_d2/Navigation?langId=-1&storeId=10051&catalogId=10053

 

[Charles (in GA)]

biggest issue is if you are going to insulate and skin inside, you need to do the area behind the panel first (assuming you are surface mounting the panel, which you almost have to). If you don't, you will be stuck trying to take everything loose and work insulation and skin behind the panel and mounts. If you are using anything corrugated, or even the skin like the outside of the building (white, best choice for inside) you will have to have spacers the thickness of the corrugations, behind the unistrut, to keep from crushing the corrugations.

If you mount the panel directly on the skin, you will have a wobbly, floppy, panel. Same issue is with the boxes, as you will go and mount a box, then a corrugation falls right under the box.

If you haven't experienced that building in the summer, you will discover its like being in a broiler. I have worked in a uninsulated steel building in west central georgia, and it is unbearable. No amount of fans or ventilation will help, you cook.

Charles

 

[HeloMech]

At this point there is no plan on insulating the garage. I've been through 2 summers here in Alabama with out a/c, just using a fan. The shop has doors on both ends, so I almost always have a decent breeze.

My electrician came out Friday and ran the wiring from my main panel in the garage to a 100 amp sub-panel in the shop. We came out through the brick and then down into a trench 2' deep coming up right outside the shop where the panel is mounted. He went up and then directly into the box. He set 2, 8' ground rods for the panel, also grounding the metal structure of the shop. We ended up mounting the box directly to the corner metal post in the shop. With self tapping screws slightly predrilled, it's mounted. It's extremely sturdy and I now have the option of coming out of the box from 3 sides.

 

[Epic Motos]

I have this same building and all my circumstances are almost identical.

@HeloMech How is that side install holding up? I thought about doing mine this way but it just seems sorta "Jerry Rigged". If anyone else would like to chime in on this method of mounting the box, I'm all ears. (My feed comes up from the floor via 3/4 PVC inside the shop which Im thinking will help give the box addtl support using this side mounting configuration. I even thought of adding a shelf bracket under it but dont want a jerry rigged looking mess. Seeking Input)

Also, To All: Ive been advised to NOT mount the panel to the structure (Or any conductive part of the structure) and to isolate it by mounting the panel to wood. Seeking input here.

BTW Nice site GJ

 

[Norcal]

This thread is from 2013 and the OP has only 39 posts doubt you’ll get a reply.

 

[Epic Motos]

@Norcal IDK it was 2013 old but also why I welcomed additional input from others

 

[grounded-b]

Also, To All: Ive been advised to NOT mount the panel to the structure (Or any conductive part of the structure) and to isolate it by mounting the panel to wood. Seeking input here.

Not mounting the panel to any conductive part of the structure makes no sense. The NEC requires you to bond the metallic structure to the equipment ground in the panel. Therefore, they are all one, electrically. It can not be "isolated"

Steve

 

[Stuart in MN]

I don't think he was talking about electrically isolated. It's typical to mount a panel on a piece of plywood, so it's not subject to condensation from being mounted directly to the metal building panel.

You are right that the building metal needs to be bonded to the panel. In any case, it all happened back in 2013.

 

[86Vette]

How does one physically bond a ground wire to the metal siding? How would you do that? A picture or link to the fitting used would be awesome. Thanks!