Steel building wiring idea

[bdog]

You may recall my previous thread about how to place the outlets in my steel building when the girts were at seven foot. I decided to buy 6" C's and make another run around the perimeter of the shop at four foot. There was no need to screw the outer panels to the girt since it was only for the outlets so I chose to run it with the 6" side vertical and the opening of the C flush against the panels.

My initial idea was to fasten 4" boxes to the girt and run EMT between the boxes but then I realized the the C girt itself was esentially like a conduit as it was enclosed. Certainly anything inside of it would be well protected from damage.

SO.... my idea was to just run the wires inside of the c channel and use a hole saw to cut holes for the wires and bring them in from the back of the boxes. I was planning on using either romex or maybe mc. I am in a rural area with no inspections or anything like that to worry about. Safety is my only concern. It seems like the wiring would be better protected this way than in conduit plus it would look really nice as the wiring would be invisible.

 

[mrb]

personally I would not run romex in a metal building. MC cable, I dont know if you could make the bend into the back of the box.

 

[GeorgiaHybrid]

Bad idea in a metal building. You are not protecting the wires, you are hiding them. That is not good when someone sees that nice pretty channel and drills a hole in it to mount something and runs a bit into the wire. Run the wiring where you can see it in EMT or use MC cable. If you have the channel in place, we used to have our guys run EMT on the bottom flange of the channel and come up into the bottom of the box.

That way someone can set something on the top flange, hang off of the flange or drill and bolt to the web of the channel if needed without bothering the wiring.

 

[Aceman]

I'd go with MC in a steel building. Another thing too, is rodents can't chew the sheath off MC like they can Romex. I personally wouldn't have any issue running it inside the C channel where it's hidden, I'd think that's a lot better than running it on top of the girt where it may be damaged.

personally I would not run romex in a metal building. MC cable, I dont know if you could make the bend into the back of the box.

They make 90 degree MC connectors.

 

[mrb]

I'd go with MC in a steel building. Another thing too, is rodents can't chew the sheath off MC like they can Romex. I personally wouldn't have any issue running it inside the C channel where it's hidden, I'd think that's a lot better than running it on top of the girt where it may be damaged.



They make 90 degree MC connectors.

i dont think those can be concealed.

 

[Aceman]

You can conceal them. MC is a cable, not a conduit.

 

[mrb]

You can conceal them. MC is a cable, not a conduit.

ah ok. I was remembering not being able to bury 90deg flex fittings, and incorrectly applying it to 90deg MC fittings. Thanks for clearing it up.

 

[sberry]

I want emt, want to be able to push or pull a new wire in if needed. One of the benifits of pipe.

 

[BoydS]

bdog ... not sure if you have decided on MC or EMT, but if not I would like to provide a bit of input that may help. I would suggest you do a cost comparision between the 2 before making a decision with which material to install. I would think the MC is more costly and doesn't allow for future wire pulls, therefore you'd need to run another MC cable if you decided to add something down the road.

I see that you are planning to add a 6" channel turned on it's side around the perimeter of your building at 4' off the floor. Not knowing the distance you have to span between columns, just make sure the channel you buy can make that span without flexing. From reading your earlier post (just went back to check), I see your columns are 25' apart. If that's the case, you'll need a pretty heafy c channel to make that span.

Although my installation may not be the best, this is how I am running EMT inside my steel building along the girts that are 4' off the floor.

 

[BigBlue1]

Hey Boyds can i see pictures of your breaker box to see how all the wires come in. Thanks Jason

 

[GeorgiaHybrid]

A small channel or Z purlin can be used as a girt. You will need to add a few sag rods from above to keep things level. Normal useage is a 1/2" rod at the third or quarter points depending upon the span. You generally don't want to exceed 6' to 7' between them.

 

[Aceman]

I can't understand all the back-back 4 sq boxes?? One facing down and another facing out as well as using pulling els instead of 90's. Do you have a bender? They're not very expensive, it only takes a little practice to start making decent offsets and 90's with one.

If you want to run your conduit under the z-channel, the easiest, cheapest way would be to run it straight under there and offset out to the box on the face of the z-channel, then come out the other side and offset back under and on to the next recep box. Pulling wire will be considerably easier than pulling through a bunch of ells and upside down 4 sq boxes.

I also run 3/4" emt as a minimum in shops. I've tried 1/2" and it works right up until the customer decides to add or change something. There isn't hardly a price difference between 1/2 and 3/4 and it isn't that much harder to run.

 

[nehog]

First time I've seen girts installed that way around, I was taught to "flip 'em over" with the inside lip facing down.

 

[Charles (in GA)]

I can't understand all the back-back 4 sq boxes?? One facing down and another facing out

I did this same thing in about three places, on a girt that was 7 ft high and the EMT on top of the girt. I did splices in the box the conduit was connected to and from the splices I used pigtails thru the close ****** to the box where the receptacles were. I don't think I could have done it all in one box (two grounds, two neutrals, two hots, both in and out, and same for pigtails to the receptacles. On the columns, the junction box is on the girt and the receptacles are down the column at about 4 ft, so its some real long pigtails to the receptacles. Makes the receptacle box very uncluttered.

First time I've seen girts installed that way around, I was taught to "flip 'em over" with the inside lip facing down.

Thats the way mine are done (inside lip down) and I don't think I've been in a unfinished metal building that had them done any other way.

Charles

 

[JBurgess]

Thats the way mine are done (inside lip down) and I don't think I've been in a unfinished metal building that had them done any other way.

Charles

It would seem dificult to put up bypass girts like these with inside flange down. It would require holding them up and bolting to the bottom of the tab on the colum.

 

[GeorgiaHybrid]

Thats the way mine are done (inside lip down) and I don't think I've been in a unfinished metal building that had them done any other way.
Charles

It would seem dificult to put up bypass girts like these with inside flange down. It would require holding them up and bolting to the bottom of the tab on the colum.

First time I've seen girts installed that way around, I was taught to "flip 'em over" with the inside lip facing down.

Generally the girts are done with the inside lip "down" and bolting to the bottom side of the column clip. This allows you to keep the top surface clean and to "hide" something behind the flange if required. I have done them with the inside lip up to make a "shelf" for cans, bottles, etc that will not fall off but about 6 months later the guy let me know that he wished he would have listened to us... He had to vacuum the "tray" that was formed every 2 or 3 weeks.

 

[Charles (in GA)]

It would seem dificult to put up bypass girts like these with inside flange down. It would require holding them up and bolting to the bottom of the tab on the colum.

Yep, mine are bolted to the bottom of the tab. Some cheap buildings don't use the tab, they drill holes in the girt flange and in the column and bolt directly to the column, but the girts sag and this is a cheaper way to do it. Mine is an MBI building out of Thomasville, GA.

Looks like you didn't install all of the bolts at the girt to tab connection, I only see one, and can see a couple of empty holes.

After my contractor left, I wondered why I had such a large amount of bolts and nuts left over, and started looking. I found about 75 places where bolts were not installed, and then I took the impact and started checking and found that about a quarter the bolts in the building were loose and never tightened up correctly.

Charles

 

[JBurgess]

After my contractor left, I wondered why I had such a large amount of bolts and nuts left over, and started looking. I found about 75 places where bolts were not installed, and then I took the impact and started checking and found that about a quarter the bolts in the building were loose and never tightened up correctly.

Charles

While that's not my building, it might as well of been. Here's a portion of my erection drawings showing to only use bolts in 2 of the 4 holes on the girt and purlin tabs.

Here's another portion of the erection drawings showing the girt flange up on the inside. I guess this going to be one those ground up or down on receptacle discussions.

 

[BoydS]

Ya'll got me thinking about the girt installation on my building, so I checked my construction drawings from the mfg. I found that the girts are installed per the mfg drawings, that being the inside lip up. I also consulated an architect at work who specializes in steel buildings and ask if one installation or the other was better structurally. The answer was no, both methods provide the same strength. He also stated it all depends on where the clips are located. I agree that it may be easier to clean the girt if they were installed with the lip down. One of the reasons I like the installation of mine is that the self tapping screws that protrude the girt are underneath vs above. To me this is a safer installation, instead of having the screws exposed above the girt.

As for the bolts, they were installed as well per the mfg drawings. I also had a box of bolts/nuts left over after the building was erected, so I did install additional ones. There were several that were installed that were not tightened, so I made sure they were. Not sure why 2 bolts instead of 4 bolts, but the mfg engineered the building and found this the minimum requirements to meet code and customers specs.

 

[Silvervic99stang]

i also have a steel building that i built, BoydS. could you share a picture of how your main electric panel is installed on the wall i am having trouble deciding on how to install it... flushed or on top of the purlin wich will make it stick out 4 inches... thanks

 

[green.bubbly]

What about grey schedule 80 pipe? Would there be any problem using this in a metal garage? I am wrapping up the erection of a 24,24 Mueller steel garage. I am not fond of working with metal pipe and the MC cable looks like it would be a pain in the ****.

PVC on the other hand, I am familiar with cutting, gluing and the fittings that are needed.

 

[Charles (in GA)]

i also have a steel building that i built, BoydS. could you share a picture of how your main electric panel is installed on the wall i am having trouble deciding on how to install it... flushed or on top of the purlin wich will make it stick out 4 inches... thanks

Here is pics of mine. The two 4 square boxes for switches was later replaced with one long 5 position box. I mounted on unistrut. Place looks like a "plumbers" nightmare.

Charles

 

[fletchccc]

It's been a while but thought I'd post here. We are erecting steel building and our area allows ROMEX to be used inside the walls (we are going to use hat channel and sheetrock the interior walls). Question is, what is the best, fastest and most cost effective way to attach the romex to the girts every 4 feet per code? (bypass girts).
I can't seem to find a clip that would perform what I need. Ideally a stacker where I could stack bundle (3) 12/2 cables in the center of the girt. But if that doesn't exist, a Caddy clip of some sort? although I can't find one that looks like it would work for my application..
Thanks in advance!

 

[Aceman]

It's been a while but thought I'd post here. We are erecting steel building and our area allows ROMEX to be used inside the walls (we are going to use hat channel and sheetrock the interior walls). Question is, what is the best, fastest and most cost effective way to attach the romex to the girts every 4 feet per code? (bypass girts).
I can't seem to find a clip that would perform what I need. Ideally a stacker where I could stack bundle (3) 12/2 cables in the center of the girt. But if that doesn't exist, a Caddy clip of some sort? although I can't find one that looks like it would work for my application..
Thanks in advance!

The reason you most likely can't find any straps is because no one I know runs Romex in steel buildings whether it may be allowed or not.

There are a variety of clips and fasteners for MC when used in steel OR wood framing.

 

[penright]

I went though the same questions here http://www.garagejournal.com/forum/showthread.php?t=348687

Some other threads that might help ...
http://www.garagejournal.com/forum/showthread.php?t=350415

http://www.garagejournal.com/forum/showthread.php?t=350751