securing outlets in metal building

[CrashTestDummy]

I'd like to start wiring our 3200 sq. ft. shop. I've read the books, and searched online, but haven't found an answer to one question that keeps nagging me. It seems that most electrical books want to help you wire your _house_. I want to wire a steel building. I guess it is simpler than I think it is, so no one sees the need to mention it.

I plan to run the wiring inside EMT, and into metal outlet boxes. What I am wondering is, how do you _physically_ secure the outlet boxes? Do you screw them directly to the building's vertical framework? Screw them directly to the horizontal framework? Secure the conduit with anchor clamps near the outlets and let the outlets just hang off the EMT? My apologies if this is a simple query, but I just don't know. Thank you.

Regards,

Gene Beaird,
Pearland, Texas

 

[Charles (in GA)]

Screwed some of mine to wall girts, some are screwed thru the I beam columns, some are secured to C channel columns. All have two 1/4-20 bolts or self threading screws holding them to the structure.

Below is the panelboard and light switches and receptacles that are located right at the panel. Light and fan switches are mounted on a piece of horizontal unistrut that runs the full width between the c columns.

Will try to get pics of receptacles later.

Charles

 

[CrashTestDummy]

Thank you very much, Charles. I can't wait to see the pictures. I'm trying to get an electrician friend to come by and give me pointers, but with his 5 kids, his after-work life is a bit hectic.

Gene Beaird,
Pearland, Texas

 

[MR P BODY]

I used the same screws that hold the building together(self tapping)zip screws... I put a
220 and 4 110 outlets(double box) on every vertical column .... plus a 220 outside the big
door and 2 110s outside(one to plug my race trailer into).... on the outside ones I backed
up the metal with a piece of 2x4 to spread the load when plugging or unplugging(it felt too
wimpy with just the metal panels

 

[mustangmccance]

I had the same question. I had the electrician that I had wire the main panel also wire 4 8 foot lights and 3 switches as well as the garage door openers all on separate circuits to get the project started. these were all run in conduit and attached to the horizontal supports. the circuit box was framed in with 2x4 and attached to the horizontal support and the floor. then I have framed in the walls in my wood shop with 2x4 again anchoring to the horizontal support and the floor. then I wired it just like a house. I use pegboard as my wall covering so it is very easy to unscrew it and get to the wiring if I want to add new circuits or whatnot. I need to get a conduit bender one of these days because I want to add new circuits in my main shop and all that wiring will need to be run in metal conduit http://community.webshots.com/photo/2870423140101642786VovjjD

thats just another way to do it.

 

[MR P BODY]

I had the same question. I had the electrician that I had wire the main panel also wire 4 8 foot lights and 3 switches as well as the garage door openers all on separate circuits to get the project started. these were all run in conduit and attached to the horizontal supports. the circuit box was framed in with 2x4 and attached to the horizontal support and the floor. then I have framed in the walls in my wood shop with 2x4 again anchoring to the horizontal support and the floor. then I wired it just like a house. I use pegboard as my wall covering so it is very easy to unscrew it and get to the wiring if I want to add new circuits or whatnot. I need to get a conduit bender one of these days because I want to add new circuits in my main shop and all that wiring will need to be run in metal conduit http://community.webshots.com/photo/2870423140101642786VovjjD

thats just another way to do it.

I ran all 12-3 w/ground for everything (it comes in the flex conduit... forget
what its called) most on it lays on the Z channel thats at 7'... if I needed to
go up and over the main beams I used zip screws and conduit clamps... makes
for real quick job. I have quite a few 220 items in my shop, lathe, mill, hoist,
compressor and multiple welders plus with the 12-3 w/ground you get 2 110
circuits per run if needed.

 

[CrashTestDummy]

Mr. Mustang,

I do plan on framing out a wall where the workbench is planned on being put, but I was thinking of just taking the EMT across the front and surface-mounting the outlets to the drywall (or OSB, or plywood, whatever I use when I get to that point). The rest of the place, though, is just insulated steel building, thus my query about how to secure the outlets to the framework, or whatnot.

Thanks, though, it's a great idea.

Gene Beaird,
Pearland, Texas

 

[Charles (in GA)]

Here are some shots of my box and conduit installation.

First one is of a 4 inch square deep box with two receptacles in it, These are wired completely separate, not multiwire, each has its own neutral and ground. There are six like this on the six columns in the building. I drilled and mounted using two 1/4-20 bolts and nuts.

Second is the same box setup mounted on a purlin seven feet off the floor. I put a shallow 4 inch box in the conduit run and pigtailed the wires in it thru a ****** to the receptacle box. It is mounted with left over self drilling screws from the building construction, as is the box in the conduit run. Later I decided I had way too much wire packed in that shallow box and added extension boxes and pulled the wire bundles apart somewhat.

Third is a four inch deep box with receptacles mounted in the back corner of the building (which is an endwall), this same setup is also in the other back corner. The other end of the building is clear span, with doors (aircraft hangar). I highly suggest NOT doing what I did. I now want to skin the walls from the purlin to the floor (by adding an extra floor angle, and skinning with 29 gauge white corrugated sheetmetal) but I am going to need to remount this box and re-bend this last section of conduit, I think these are mounted with the 1/4-20 bolts and nuts.

Fourth is a shot up the back end wall of my electric panel and conduits. Looks like a plumbing maze. To the left of the panel is a box with a single GFCI and a light switch. This is the original installation in the building to get the permit. The light switch controls two cheap 500 watt quartz flood lamps. You can see one of the floods in the upper RH edge of the pic. There are two on the back end wall, 30 ft apart. The amount of light they give off is amazing. I used this system for eight years until I mounted the metal halide lighting last year. The receptacles below are for a welder, a 240v/20amp portable air compressor I no longer have, a 120v/20 amp receptacle for those rare cases where I might actually need to plug in a 20 amp plug (I do not even own anything with one on it) and as an afterthought I added the two receptacles in the four inch square box.

The last pic is a shot of the other 500 watt quartz flood and the conduits coming across the top of the 14 ft garage door (on the right). The feed receptacle circuits, that light, and the stationary air compressor circuit.

You can see my lighting installation thread here.....................

http://www.garagejournal.com/forum/showthread.php?p=275442#post275442

And my ceiling fan installation at the bottom of this thread on 60 inch ceiling fans.............here................................

http://www.garagejournal.com/forum/showthread.php?p=303048#post303048

Hope this helps, Charles

 

[CrashTestDummy]

Yes, very much. Interesting. The purlins (horizontal framework) on our building are upside down, compared to yours. That is, the end that faces inside the building turns up, creating a little shelf, instead of down. To get what you have, I'd have to clip the conduit to the bottom of the purlins.

That's great info, though, thanks.

Gene Beaird,
Pearland, Texas

 

[GeorgiaHybrid]

Nice looking install Charles. It looks like you might have used a conduit bender a few times in the past before starting this project.

 

[CrashTestDummy]

We have power!! I added two dual outlets today, one GFCI and the other a simple 20A dual outlet. Ran conduit under the perlins, secured with single-screw clamps, and screwed the outlet boxes directly to the perlin faces. Ran 12-3 romex (just because it was easiest to buy) in 1/2" conduit. I bent the conduit so it would turn out to meet the boxes. It only took me 6 hours and $175 (well, we did get some other stuff at the hardware store) to run everything, but we got it all hooked up. I was annoyed that nothing worked after hooking it all up and throwing the BIG SWITCH, but after chasing voltage out of the breaker box and pressing the reset button on the GFCI outlet, I could recharge the battery on my cordless Makita drill.

Next step? Drag the shop vacuum to the shop so I can vacuum out my 86 SVO tub before installing the new carpet I got for it. Thanks for ALL the help!!

Gene Beaird,
Pearland, Texas

 

[Charles (in GA)]

Nice looking install Charles. It looks like you might have used a conduit bender a few times in the past before starting this project.

Not.............. I mis-bent quite a bit. Seemed I had to re-learn it each time I started over after a long hiatus away from it. While I did not find it in time to be of much help, I think this paper is the best help for bending conduit I've found......................

http://www.mikeholt.com/documents/freestuff/BendingRoundRaceways.pdf

Its a paper put together by an instructor at Albany Technical College in Albany, Georgia.

Gene, go ahead and spend the money, buy a 500 ft reel of black, white, and green and one of those reel holders. Also get a large bottle of wire pull lube. Get a pile of DEEP 4 inch boxes, face plates, covers, etc. A big bag of end fittings, another big bag of conduit connectors, a big bag of one leg conduit clamps, a huge bag of wirenuts, and a box of green screws to ground wires or jumpers to the boxes. It seems like alot, but it will be there anytime you take a notion to run a new circuit. I did mine one circuit at a time, and quickly realized it was a waste to keep buying stuff over and over, so I bought quantities of everything.

Charles

 

[CrashTestDummy]

Yeah, I pretty much bent a stick of conduit up. I guess I should have bought an extra stick just to practice bending on. I ended up using it anyway, out of disgust, and really not caring because the conduit would be out of sight anyway.

I figure the next step is to get case counts of stuff before starting the whole wiring project. I have an electrician friend who said he'd come by and help me map out what I need, and even let me get the parts I need under his company name, give me some pointers and even loan me some tools. I was getting pretty frustrated needing just a single outlet to plug some simple tools into that I just ran out and got the stuff and did it. I ran romex through the conduit, instead of getting rolls of separate wire, again, hoping that my friend will soon come through.

And yeah, even the 2" deep outlet boxes I got weren't deep enough for the gfci outlet. I'll have to replace that one. I also discovered that even thought they have all the parts and bits out in boxes in the same area, stuff doesn't necessarily go together, and you really need to test fit before you make a big purchase. I got some nice wallplates, but they don't work without a wall to install them against. So, I'll have to search for something else next time.

But, I now have power in the shop!! I'm so jazzed.

Gene Beaird
Pearland, Texas

 

[Charles (in GA)]

You want the stamped industrial face plates like I have. I have one box on the opposite side of the garage door from the light switches, that has two GFCI receptacles in it, in the stamped steel 4 inch box cover. No extra face plates are needed.

Charles

 

[Falcon67]

Thanks very much for the link to the paper - I can build engines, transmissions, garages, paint cars, weld - can't bend tube for s$&t.

 

[GeorgiaHybrid]

Falcon,

It's an arcane art form that is only practiced by electrical wizards. They arive in the dead of night, make sacrifices to the electron gods that invoke the ground, copper metal and lightning from above. They can then have their way with helpless homeowners after killing their pet wallets and they answer to no one except the highest power in the land.... The dreaded tax collector... The most evil of all......

 

[ixlr8]

Charles... as we have no zoning laws in my small town, I was just going to run 12-2 wire from one box to the next and not bother with the EMT. Your well laid out, neat, organized setup has shamed me into spending the time to do it right!

 

[Falcon67]

Falcon,

It's an arcane art form that is only practiced by electrical wizards. They arive in the dead of night, make sacrifices to the electron gods that invoke the ground, copper metal and lightning from above. They can then have their way with helpless homeowners after killing their pet wallets and they answer to no one except the highest power in the land.... The dreaded tax collector... The most evil of all......

I hear that - and I mean any kind of tube. You have no idea how much brake tubing and fuel line I've sacrificed at the Alter of the Mangling Bender.

 

[Charles (in GA)]

Charles... as we have no zoning laws in my small town, I was just going to run 12-2 wire from one box to the next and not bother with the EMT. Your well laid out, neat, organized setup has shamed me into spending the time to do it right!

Even if you are not required to adhere to codes, your insurance company will expect you to, and might look hard at denying claims related to non-code fires, and other incidents.

I think I may have overdone the conduit, but I wanted something that would last and never have to worry about damage from either humans or animals.

You will actually spend more time standing in the building, staring and thinking, running various possibilities in your head, than you will doing the work.

Buy a cheap bandsaw if you don't have one. I have a Northern Handyman band saw, and used it extensively for this. Makes square cuts, exactly where you want them, and excellent for cutting unistrut.

Get a multi step conduit reamer tool. Klein makes one with a screwdriver like handle. I found the same tool, designed to slide over a screwdriver and lock with a set screw, on clearance at Home Depot (its Klein also) and I bought it and put it on an old screwdriver that was no good for anything else.

Get a 1/2" EMT bender, and also get a fish tape, and get a good one, greenlee or Klein or other name brands. They tend to work easier than the cheaper ones. Get several tape measures, I never remembered to pick up mine when I got off the scissor lift, or back on it, you need several laying around on ladders, lifts, bandsaw, etc.

Having a helper is well worth it, especially when doing the wire pulls. You need someone to feed the wire and spread lube on it. I did it by myself, and made many trips back and forth from the pulling end to the pushing end. Lots of time wasted.

Charles

 

[andrew22]

its always a good idea to have all the major outlets of electric wire outside the metal buildings

 

[Charles (in GA)]

its always a good idea to have all the major outlets of electric wire outside the metal buildings

I'm sorry, but I don't understand what you are trying to say. Would you try again?

Welcome to the board too!

Charles

 

[protegeV]

This is amazing info. Just what I needed. The crazy part is I searched and searched via GJ and couldn't find this thread, but I found it through google.

I'm having an electrical company run the main line from the house down to the shop tomorrow and install a panel. My neighbor convinced me I could do all the wiring inside the shop myself with his help.

 

[alfredeneuman]

Ran 12-3 romex (just because it was easiest to buy) in 1/2" conduit.

The Code says a single NM cable only can use 54% of the area of the conduit.

A 12-3 exceeds that by far in a 1/2 EMT