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Discussion Starter · #1 · (Edited)
I would first like to say this isn’t my first post here but I haven’t logged in in over 10 years so I just made a new account. (Don’t remember my login and don’t have that email any longer) I’ve missed the discussions and knowledge this forum provides, life has just been happening haha…..anyway……

I’ve searched the forum but couldn’t find anything on this. How do you guys mount Receptacle/Switch boxes in steel buildings and get the circuit to it? Im talking about the red steel buildings with I-Beam columns every 20’ - 30’ and horizontal z-channel type purlins. (Not the thin, shiny, square tubing, carport style buildings)

As you know the devices always need to be in between the purlins usually @ 4’. I’ve usually just put a vertical strut between purlins and mount the metal box to it. I just feel like there’s a better, cleaner way so I wanted to get other opinions. I’ve also tried mounting receptacles upside down on the bottom of the upper purlin but not a fan of that either. How do you guys do it? Thanks!

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Welcome back
Pictures if you can, they post real easy now.

Cowboy
 

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Are they going to cover the inside or leave it open?
If open get some metal studs, screw to top and bottom. This will give you a pretty solid mounting for the electrical box. If you need to get on the red iron then beam clamps. You will get good at offsetting.
If I can for equipment I will use the middle Z beam and run my conduit up there. Z beams are usually about 8" deep and a 1.5" lip. Makes for a longer machine connection but the boxes screwed to the Z are not going any where.
Switches are harder as the door frames are not really set up for any attachments.
Hat channel or a stud cut for a bridge works.

Hex head self tapping screws work much better into the red Z beams. Phillips are just frustrating for me. I use 1/4" bit less expensive.

If you run into an box that really needs to be where it need to be your stuck with building a frame work to support the box.

I would encourage you to purchase the materials from a building supply that does metal studs and the like materials. The box stores will eat your lunch on cost of the self tappers.

Communicate with the contractor and owner so your not running wiring somewhere it will be in the way.

I just finished my metal building 70 x 30. 1200 for living the rest for my shop/garage.
 

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Discussion Starter · #5 ·
Are they going to cover the inside or leave it open?
If open get some metal studs, screw to top and bottom. This will give you a pretty solid mounting for the electrical box. If you need to get on the red iron then beam clamps. You will get good at offsetting.
If I can for equipment I will use the middle Z beam and run my conduit up there. Z beams are usually about 8" deep and a 1.5" lip. Makes for a longer machine connection but the boxes screwed to the Z are not going any where.
Switches are harder as the door frames are not really set up for any attachments.
Hat channel or a stud cut for a bridge works.

Hex head self tapping screws work much better into the red Z beams. Phillips are just frustrating for me. I use 1/4" bit less expensive.

If you run into an box that really needs to be where it need to be your stuck with building a frame work to support the box.

I would encourage you to purchase the materials from a building supply that does metal studs and the like materials. The box stores will eat your lunch on cost of the self tappers.

Communicate with the contractor and owner so your not running wiring somewhere it will be in the way.

I just finished my metal building 70 x 30. 1200 for living the rest for my shop/garage.
I like that thanks! Your comment made me think about using the track they put the metal studs into to build walls. Seems like they would work great for this. Ever tried them? I think it would be a clean look.
 

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I. Use angle iron. Size and gauge dependant on what you are hanging on it. Notch the ends of the rearward facing flange, to get it to sit flat against the face of the purling.

Use industrial grade drill screws to mount the angle and your conduit and boxes.

If you need more mounting space use some plywood between supports.

I used this method to hang control panels for years. Buy the metal from a steel supplier, cheaper than strut and hardware.
 

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Chief Flunky
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Get strut clips. Two of them bolt the strut to the steel column. Bolt box to strut. Most have holes for this. I used to buy spring nuts but these are expensive and a pain to work with unless you need holding. Now we buy these strut nuts with a cone shaped plastic piece that is much easier to work with and cheaper. If you need to reposition or remove or do anything it’s easy to do,

Welding angle or even the strut is cheaper but depending on the customer they may frown on this as well as drilling holes not in the webbing. Strut clips don’t require welding or drilling so save time too.

You’ll find that most electrical hardware such as strut is fairly expensive for what it is but it’s a material cost/labor cost trade off.
 

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Discussion Starter · #10 ·
I. Use angle iron. Size and gauge dependant on what you are hanging on it. Notch the ends of the rearward facing flange, to get it to sit flat against the face of the purling.

Use industrial grade drill screws to mount the angle and your conduit and boxes.

If you need more mounting space use some plywood between supports.

I used this method to hang control panels for years. Buy the metal from a steel supplier, cheaper than strut and hardware.
What gauge would you use for receptacles? We talking something you can notch with snips or does it require a cutoff wheel or bandsaw?
 

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Hackenschmidt
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You could always use 2x4's screwed into the purlins with Tek screws, let the 2x go all the way to the floor.
 
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I hate that type of building. Its hard to do anything in them. I would use steel beam clamps and 1 hole straps with threaded holes or bolts and nuts. You also have a nice flat ceiling grid. Try to use that. Then you can come down for your box.
The motor shop I worked in was this type of building. Seems every motor shop within a 100 mile radius has the same type of structure.
 

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Standard angle iron thickness is 1/8", needs to be cut with a band saw. I took a quick look at online pricing in my area, 1/8 x 1.5 x 1.5" angle iron was $ 1.50 per 10' cheaper than 1 5/8" strut. Iron from steel suppliers comes in 20 or 21' lengths. You can get better pricing if you know a fab shop or contractor that buys steel from the steel vendor, and piggyback on one of their orders. Depends on how much you need. And cabbage can be your friend when buying small quantities from other shops.

I feel that the advantage to angle iron is it's much easier to run the pipe and boxes. No need to offset out onto unistrut or 2x4's extra depth. No expensive strut hardware, strut clamps. All that is required is quality drill screws, a portable band saw and some one hole straps. Iron is also customizable, longer lengths if needed, can make the horizontal connections just as easy, can be welded together to make a rack for equipment and panels. Can also easily weld feet on to anchor to the floor when required.

Something else that can be obtained from sheet metal duct-work suppliers is sheet metal angle. They use it for legs to support duct runs. It's lighter and likely cheaper and made of galvanized metal. I haven't used it on my jobs because I normally do industrial equipment and it's not sturdy enough, but for a switch or outlet box it may be sufficient, it could be used in the same fashion. It would depend on your span length.

Here is an example, you would need to do some homework in your own market. A tin knocker could advise you where to find it or order it for you. Networking with other shops or fabricators is a decent way to cut your costs on this type material.
Angle 1.5" x 1.5" x 10' 16GA

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Hackenschmidt
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Check out the Dakota Receivers might be a quick easy way to do what you are looking to do. DAKOTA RECEIVERS
These are definitely something I'd try out. I am curious what they cost compared to a regular spring nut or cone nut. Spring nuts can be a real pain in the ass and you have to keep two sizes on hand for the regular strut and the shallow strut. Cone nuts are easier but they do twist out of the desired position. These can't twist out.

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I just looked up one brand of regular spring nuts, the 1/4-20 are rated for 450# pull out load. These 1/4-20 receivers are much less metal and are rated for 200#, but I don't see that as a deal breaker, that is adequate for most of what I do with 1/4-20 hardware. Certainly adequate for mounting boxes. The 3/8 receiver is rated for 250, that would be less useful - usually if I am using 3/8 I want the extra strength.

With this the box wouldn't be touching the strut, just the receiver - the receiver creates a little gap between the strut and the mounted equipment. You could still slide the equipment with the 1/4-20 screw tight. I could see that being a good thing in some situations, a bad thing in some situations. Now that I think of it, in this particular application, mounting a box on vertical strut, I think it would be a bad thing - is the box really secured if it can slide? But I still want to try them.

I checked the "where to buy" links on Dakota's web site, like most where-to-buy's, half of them I couldn't even find this product. This one had them for $1.20 which is a bit much even for a made in USA strut nut, but I think that store's pricing is high all around, I am betting I could find them cheaper. But at that price I'll buy at least 25 or 50 just to try them out and have on hand.

A similar product would be the Caddy MFA4I which is pretty cheap, < $0.50, but is only rated for 100#. I never tried them, they look a bit flimsy for 1/4-20 hardware. Although two or four 100# rated fasteners would be adequate for mounting a lot of things. It snugs the box to the strut, so it would not slide.
 

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When its a residential/lite commercial customer : i use treated 1x4 wood for plugs and switches. Screw it directly to the face of the purlins top and bottom. More often i screw the top to a purlin and use an angle bracket plate on the floor. Hammer drill and anchors to cement floor. The angle brackets are available at the blue box store in the carpentry section. I use a piece that is 3" by about 6" long and 90 bend across the middle, it lets you get 2 or more screws in the board and the floor, usually sturdy enough for just a plug. If the panel is small i use 1x4 for that too. I use treated because of condensate/sweating issues.
i use strut for heavy or industrial, preferably i get the mill welder to make two vertical pieces of purlin, weld or bolt to building purlin and then bolt my strut to that horizontally.
 

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We have full fab capability and will do up nice racks for lots of gear or mechanical equipment but for just a single box or watever I usually just take some plain ol slotted strut and my portaband and zip off the sides leaving just the back. Either do that on the other end if I have 2 girts to mount between and zip it on with teks and fender washers or use a strut foot on the bottom if you just have concrete.
 

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These are definitely something I'd try out. I am curious what they cost compared to a regular spring nut or cone nut. Spring nuts can be a real pain in the ass and you have to keep two sizes on hand for the regular strut and the shallow strut. Cone nuts are easier but they do twist out of the desired position. These can't twist out.

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I just looked up one brand of regular spring nuts, the 1/4-20 are rated for 450# pull out load. These 1/4-20 receivers are much less metal and are rated for 200#, but I don't see that as a deal breaker, that is adequate for most of what I do with 1/4-20 hardware. Certainly adequate for mounting boxes. The 3/8 receiver is rated for 250, that would be less useful - usually if I am using 3/8 I want the extra strength.

With this the box wouldn't be touching the strut, just the receiver - the receiver creates a little gap between the strut and the mounted equipment. You could still slide the equipment with the 1/4-20 screw tight. I could see that being a good thing in some situations, a bad thing in some situations. Now that I think of it, in this particular application, mounting a box on vertical strut, I think it would be a bad thing - is the box really secured if it can slide? But I still want to try them.

I checked the "where to buy" links on Dakota's web site, like most where-to-buy's, half of them I couldn't even find this product. This one had them for $1.20 which is a bit much even for a made in USA strut nut, but I think that store's pricing is high all around, I am betting I could find them cheaper. But at that price I'll buy at least 25 or 50 just to try them out and have on hand.

A similar product would be the Caddy MFA4I which is pretty cheap, < $0.50, but is only rated for 100#. I never tried them, they look a bit flimsy for 1/4-20 hardware. Although two or four 100# rated fasteners would be adequate for mounting a lot of things. It snugs the box to the strut, so it would not slide.
Hey sorry for late response but here is a couple of answers to your questions... You can find them on McMaster Carr for around $1.38. Though you are prolly better off going to Graybar or CED and asking the counter as they are usually around $0.85.

As for the load rating as we are UL certified they require all of our loads be listed as 3 times safety factor. So our load on the 1/4 is listed at 200lbs but in realty that is 600lbs pull force before failure. Same goes for the 3/8 receiver which is 250lbs but with 3 times safety factor allowing for 750lbs of pull force before failure.

So there is a small gap between the box the receiver. We do have two sperate receivers one with barbs and one without barbs. The barbs on the surface of the receiver are there to reduce spin when screwing the box into place as the barbs lock into the back of the box. This does result in a little larger of a gap though (roughly a 3 mm gap). To answer your question the receivers do slide but does take a fairly hard push to slide as the receivers are designed with locking barbs to dig into the strut. The slide is useful as it allows for quick fixes to mistakes when making alignments, but does minimize your ability to mount boxes on a vertical placed strut.

I would be happy to send you some samples if interested in seeing how the product works in person if so please just message me on my profile or leave a message with your address on our website on the contact page and I will send you a few to try for yourself.
www.dakotasystemsusa.com

Thanks
 

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Hackenschmidt
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Thanks for the detailed reply, I appreciate it and appreciate the offer for some samples, I will PM you.
 
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