Running romex in C-Purlin.

penright · Dec 30, 2016

The metal building is basic poles with C-Purlin wrap around it. The size is 30' wide by 24' deep. 4 trusses, one end and two in the middle. I will include some pictures to help describe. My thought is to use some of the C-Purlin as a chase for romex or MC.
Here is my introductory thread (http://www.garagejournal.com/forum/showthread.php?t=348413

What is the best way to attach boxes to C-Purlin? I have a electrician buddy looking for 4 foot T8 good or bad ballast, I don't care. I need the non-shunted tombstones so I can direct wire some 4 foot T8 LED's that I have. I have two garage doors to consider in light placement.

To use the C-Purlin as a chase, I was going to get some 4" flashing to use as a cover. 50' of aluminum flashing is $12 a roll. That works out to about $.24 a foot. 12/2 W ground romex 250' roll is about $54 or $.21 a foot. Compatible MC is $97 for 250' feet or $.39 a foot. Thats a delta of $.18 a foot. I am making the assumption that the panel ground is bonded to the building. That would keep the building from becoming energized if a hot wire rub though in the chase. There was some discussion (among us jake-leg) about doing that. I sure the electrician will know when he makes the connection what code is, but mean while the discussion is .... This house was built in 2015, so my sub panel falls into the 2011+ rules. I will have a ground from the house with the two hots and neutral. The neutral will not be bonded to ground at the sub panel. I have two 8ft ground rods for the sub panel. The fear of bonding the building to ground, was if lightning struck the building and the ground could not carry it, would it backfeed to the house? My thought, if I screw metal boxes to the purlin then I bonded it anyway.

I think I can go horizontal 3/4 the way around. The front with the doors will trickey. The riser for the panel is about middle back wall. The other tricky part is how to go vertical? Maybe use a hole saw through the side and connect perlin above or below with conduit? I don't think the horizontal carries any load, other than siding, does it? If so what direction? Maybe a combination of romex where possible and then MC when I need to leave my chase. If I plan so there was an outlet, that would give me a transition spot.

Don't have my electrical laid out yet, still thinking out loud. It maybe another 2 weeks before I get to it. I need to get the sub panel installed, inspected, and just a couple of outlets and lights to start with. I need that to build shelfs and work in the evenings. Since I have to move stuff from various storages, it will be in the way until I can organize some.

My Home Automation supports z wave, zigbee, and IP. I plan putting the lights on it. One of the 4 windows can be seen from the house, it would be nice to be able to turn a light off that was accidently left on.

My service conduit is 1 1/2", but all I could find is 2" sweeping 90, so that is what I had to use for the riser and step it down to the 1 1/2". That other one next to it is 1" that I ran separate for any future low voltage.

This shows the purlin on the back side.

This is looking at the north bay. There is another 10' that will be shelf and storage on the other side of the overhead door. Also you see the entry door.

This is looking at the south bay. There is not any room between it and the south wall.

This is of the front so you can get idea of proportions.

matt_i · Dec 30, 2016

Code issues aside, securing the sheetmetal cover to the channel is going to be with...sheetmetal screws? I would be worried about the sharp points penetrating the chase and the NM being an easy target. The MC would be my choice.

ishiboo · Dec 30, 2016

penright said:
The metal building is basic poles with C-Purlin wrap around it. The size is 30' wide by 24' deep. 4 trusses, one end and two in the middle. I will include some pictures to help describe. My thought is to use some of the C-Purlin as a chase for romex or MC.
Here is my introductory thread (http://www.garagejournal.com/forum/showthread.php?t=348413

What is the best way to attach boxes to C-Purlin? I have a electrician buddy looking for 4 foot T8 good or bad ballast, I don't care. I need the non-shunted tombstones so I can direct wire some 4 foot T8 LED's that I have. I have two garage doors to consider in light placement.

They're thick enough that I would drill two small holes and tap to 8-32, and then use two standard electrical (machine) screws to secure the box.

To use the C-Purlin as a chase, I was going to get some 4" flashing to use as a cover. 50' of aluminum flashing is $12 a roll. That works out to about $.24 a foot. 12/2 W ground romex 250' roll is about $54 or $.21 a foot. Compatible MC is $97 for 250' feet or $.39 a foot. Thats a delta of $.18 a foot. I am making the assumption that the panel ground is bonded to the building. That would keep the building from becoming energized if a hot wire rub though in the chase. There was some discussion (among us jake-leg) about doing that. I sure the electrician will know when he makes the connection what code is, but mean while the discussion is .... This house was built in 2015, so my sub panel falls into the 2011+ rules. I will have a ground from the house with the two hots and neutral. The neutral will not be bonded to ground at the sub panel. I have two 8ft ground rods for the sub panel. The fear of bonding the building to ground, was if lightning struck the building and the ground could not carry it, would it backfeed to the house? My thought, if I screw metal boxes to the purlin then I bonded it anyway.

If this is as new as it looks, probably should have used the UFER ground instead of driving ground rods.

Lightning wants to make it to ground. The building definitely needs to be grounded as does the panel. If by chance it makes it over the ground to the house, it's perfectly capable of doing the same over a hot. The 1/8" gap between hot wires and some 600V insulation is nothing for lightning, which at potentially 100 million volts has no problem traveling 100 miles in open air.

Do it right, use proper surge suppression at the panels and don't worry about it.

I think I can go horizontal 3/4 the way around. The front with the doors will trickey. The riser for the panel is about middle back wall. The other tricky part is how to go vertical? Maybe use a hole saw through the side and connect perlin above or below with conduit? I don't think the horizontal carries any load, other than siding, does it? If so what direction? Maybe a combination of romex where possible and then MC when I need to leave my chase. If I plan so there was an outlet, that would give me a transition spot.

The horizontal purlins keep the building from racking - resisting wind loads, basically. On a "C" the only part that should be drilled for anything substantial would be the back longest part, neither the top or bottom of the channel should be drilled.

Don't have my electrical laid out yet, still thinking out loud. It maybe another 2 weeks before I get to it. I need to get the sub panel installed, inspected, and just a couple of outlets and lights to start with. I need that to build shelfs and work in the evenings. Since I have to move stuff from various storages, it will be in the way until I can organize some.

My Home Automation supports z wave, zigbee, and IP. I plan putting the lights on it. One of the 4 windows can be seen from the house, it would be nice to be able to turn a light off that was accidently left on.

Remember with a metal building, Z wave may not make it between the two as you've created a giant faraday cage. If you get lucky it will due to the windows, otherwise you'll need to repeat or go over IP between the two.

ishiboo · Dec 30, 2016

matt_i said:
Code issues aside, securing the sheetmetal cover to the channel is going to be with...sheetmetal screws? I would be worried about the sharp points penetrating the chase and the NM being an easy target. The MC would be my choice.

I agree, and the other thing is that thin of metal is going to be wavy and look like **** covering the channel.

Since it's such an easy run, I would use EMT. 3/4" around the whole building in the C channel to steel boxes. I know 12/2 was planned, but i would run a MWBC with two #12 hots for two 20A duplex receptacles at each outlet location.

In the future, a second 1" could go around for higher-amperage like welder outlets.

penright · Dec 30, 2016

ishiboo said:
probably should have used the UFER ground

Never heard of a UFER ground. I actually have not driven the rods yet. I was going to drive them external to the slab.

I wonder if what I have in the building will work.
There are 10 piers. If I remember right each one is 3' deep at least a foot in diameter. The poles are welded to a plate that has 4 rebar welded to it about 3 feet long. Also there are 6 plates with about 6" of rebar welded for the door and 2 overhead doors frames. So all that rebar is enclosed in concrete per what I quickly read about CEE.

If I remember right, code just says minimum ohm for ground. How is that measured?

penright · Dec 30, 2016

ishiboo said:
but i would run a MWBC with two #12 hots for two 20A duplex receptacles at each outlet location.

Using my jake-leg understanding ....
MWBC, is that romex with the red wire? For example what they used for the dishwasher/garbage disposal? In my example they switched the red wire.

I think I hear what you're saying. By having two duplex, which I was thinking anyway, that gives me a chance to balance the load at any given spot.

250' of 12/3 with ground is $102 almost twice the cost of 12/2. Who would have thought that one extra wire would double the price? They have to be making a great margin on the 12/3 or the 12/2 is priced somewhat as a leader item.

AndyA · Dec 30, 2016

ishiboo said:
They're thick enough that I would drill two small holes and tap to 8-32, and then use two standard electrical (machine) screws to secure the box.

The drilling then tapping is going to be a pain. The self-driller self-tapper screws will be fast and easy.

I'm assuming your perlins are 14ga or thicker. Anything thinner will likely strip the thread. I'd switch to drill and pop a rivet for thinner stuff.

penright · Dec 30, 2016

matt_i said:
I would be worried about the sharp points penetrating the chase and the NM being an easy target.

Good point.

ishiboo said:
I agree, and the other thing is that thin of metal is going to be wavy

I agree. I was in my mind think which way to "un-roll" so it would lay flat. The fact that someone else brought up the concern is enough to forget it.

ishiboo said:
1" could go around for higher-amperage like welder outlets.

I can't remember the exact length, because of restrictions at the old house, when I made my welding cart, I wired up 30ish feet of #6 SO cord. I forget what the letters were exactly, but it was grease resistant, so it was SOxxxx. The cart carries the old Lincoln cracker box, mig, and bottle. There was enough room, that I wired the SO so that it passed through the Lincoln to an outlet, for the mig to plug into. I say all that so probably will store the welder and compressor in the area of the panel. So the "welder" outlet will not be a far run. Also, like I did at the old house, I will use a peice of #10, for the compressor outlet. My old house the porch outlet was about as far from the house panel as you can get, with who knows how many other on that circuit. It would not carry the smoker. So, the garage shared the outer wall with the porch and the compressor outlet was a short run and it was #10, so I just punch through the wall and put a outlet there. Never had another issue with the smoker.
At the new house, I will store the smoker in the shop, but I have not tested the outlet that on the porch. If I needed an outlet outside for the smoker, then it would have to be on the front, then I would have a decent run from it's panel. The old house was out in the country (no permits), so the outlet may have been overloaded with the smoker. The new house may not have the same issues.

ard · Dec 30, 2016

Just drive two ground rods, much easier than getting the proper equipment to meausre ground resistance. You can look it up, code says 'if you cannot prove under 25ohm, drive a second'... im paraphrasing.

I would run EMT. Its not that hard to work with, buy a bender, or two, have at it. It will create more value, plus should you need future circuits you can easily add wires. As above, one or two 'rings' around the building, then a box where you need a drop, or to go up. Maybe need to ask: will you be covering the walls or any improvements planned on the walls?

penright · Dec 30, 2016

ishiboo said:
Remember with a metal building, Z wave may not make it between the two as you've created a giant faraday cage. If you get lucky it will due to the windows, otherwise you'll need to repeat or go over IP between the two.

I hear you. You and my realtor are dream killers. Her when she said I was not be realistic about building a 2000 sq foot house, land, and drive for $100 a foot. Ok, maybe I am leaving in the 90's.

The good news, is distance will not be a problem. Controller is in the room, whose window looks out toward the building. The building has a window there also. Bad news they are not line of sight. So I don't know what going to happen. :dunno:

You do have my curiosity up enough, I have a power strip I made with a dry contact switch. It may be worth plugging it into a extension cord and moving it around the building and see if I can switch it.

penright · Dec 30, 2016

ard said:
Just drive two ground rods, much easier than getting the proper equipment to measure ground resistance

Done, back to plan A.

ard said:
Maybe need to ask: will you be covering the walls or any improvements planned on the walls?

Not at this time. It has 3" of insolation, for me to add more, doing the ceiling would be fun. Not sure what value there would be in doing just the walls.
I will put up some peg board and I have these bolt bins that flip open.

Now I am picturing the boxes to the on the open/face part of the C. To get vertical, if I put one below the panel, from the panel I can bend in toward the wall, then bend out for the box. For horizontal, then bend into the perlin till I get to the next box.
Of course to your point, then I would have the short distance on either side of the EMT coming out of the wall. They don't make a T for EMT do they?

Unless someone points something else out, I kind of like that in my mind. Of course the biggest issue of picturing in my mind, there is a lot of room for it to rattle around. :willy_nil

penright · Dec 30, 2016

ishiboo said:
but i would run a MWBC with two #12 hots for two 20A duplex receptacles at each outlet location.

After doing some research, I think I understand. Here is a link that I am basing my questions on. http://inspectapedia.com/electric/Multi_Wire_Electrical_Circuits.php
This link reminded me that I needed GFI http://www.garagejournal.com/forum/showpost.php?p=6201154&postcount=6

Now if I understand how GFI works correctly, you can not have a Multiwire Branch Circuit (MWBC) and GFI. Would not the GFI see the load imbalance on the neutral and trip?

ishiboo · Dec 30, 2016

penright said:
After doing some research, I think I understand. Here is a link that I am basing my questions on. http://inspectapedia.com/electric/Multi_Wire_Electrical_Circuits.php
This link reminded me that I needed GFI http://www.garagejournal.com/forum/showpost.php?p=6201154&postcount=6

Now if I understand how GFI works correctly, you can not have a Multiwire Branch Circuit (MWBC) and GFI. Would not the GFI see the load imbalance on the neutral and trip?

A GFCI would work at each outlet location, or a GFI breaker would work for the whole MWBC. (In addition, you can split off a single circuit protected by one up-stream GFCI receptacle on the MWBC, but let's not go there.) A two-pole 240V GFCI looks at both hots and the neutral.

A MWBC would let you run two hots (and both black are fine since you'll probably be doing THHN in conduit it would be cheaper/easier, though you could do 12-3 NM-B in the conduit as well) as well as a single neutral. I don't do a lot with steel boxes with conduit, but I believe you are still allowed to use the boxes/conduit as the ground, so you would just need the hot/neutral wires, but let one of the more knowledgeable folks confirm that. I would personally run a ground anyway.

Then at each outlet location, you could either do a split duplex so the top was on one leg and the bottom on another, or (my preference) two side-by-side duplex receptacles with one on each leg of the MWBC.

penright · Dec 30, 2016

ishiboo said:
(and both black are fine since you'll probably be doing THHN in conduit it would be cheaper/easier

I did not think of that. You can get whatever color $43 for a 500 foot spool. That would go around the whole building 5 times. To compare apples to apple (500/(3*43)) comes out to $.144 a foot compared to the romex at $.21 a foot. But when you jump to the MWBC (500/(4*43)) comes out to $.344 a foot compared to the romex at $.40. Like you said, THHN would take up less conduit space.

Edited: 12/30/2016 2:45pm cst.
I forgot to ask, does it matter as far as solid or stranded?

ishiboo said:
A GFCI would work at each outlet location, or a GFI breaker would work for the whole MWBC. (In addition, you can split off a single circuit protected by one up-stream GFCI receptacle on the MWBC, but let's not go there.) A two-pole 240V GFCI looks at both hots and the neutral.

I am assuming you are talking breaker. Did some searching, I have a Eaton BR, a 20amp is $111 and a 50amp is 103.
Also the panel came with some breakers, but they are not GFI. Only the outlets would have to be GFI, correct? Lights and welder would not have to be, correct? Somewhere I read if the outlet is dedicated to a device. Now I not sure if that means hardware in or not.

dw1 · Dec 30, 2016

penright said:
I did not think of that. You can get whatever color $43 for a 500 foot spool. That would go around the whole building 5 times. To compare apples to apple (500/(3*43)) comes out to $.144 a foot compared to the romex at $.21 a foot. But when you jump to the MWBC (500/(4*43)) comes out to $.344 a foot compared to the romex at $.40. Like you said, THHN would take up less conduit space.

Edited: 12/30/2016 2:45pm cst.
I forgot to ask, does it matter as far as solid or stranded?

I am assuming you are talking breaker. Did some searching, I have a Eaton BR, a 20amp is $111 and a 50amp is 103.
Also the panel came with some breakers, but they are not GFI. Only the outlets would have to be GFI, correct? Lights and welder would not have to be, correct? Somewhere I read if the outlet is dedicated to a device. Now I not sure if that means hardware in or not.

If its a receptacle in your "Garage" it has to be gfi protected, gfi must be accessible. Stranded is easier to pull. If you use MWBC and have gfi receptacles on them, sometimes you can get nuisance tripping from them sharing a neutral. You can use regular circuit breaker, feed gfi recept and then run up to 4 outlets off load side, that would probably be the most economical way. You could run 2 pieces of vertical unistrut to mount your panel, you could mount directly to strut or sometimes I will put a piece of 3/4" plywood on it (cut it down to size needed) Looking good!!

ard · Dec 31, 2016

penright said:
Done, back to plan A.

Not at this time. It has 3" of insolation, for me to add more, doing the ceiling would be fun. Not sure what value there would be in doing just the walls.
I will put up some peg board and I have these bolt bins that flip open.

Now I am picturing the boxes to the on the open/face part of the C. To get vertical, if I put one below the panel, from the panel I can bend in toward the wall, then bend out for the box. For horizontal, then bend into the perlin till I get to the next box.
Of course to your point, then I would have the short distance on either side of the EMT coming out of the wall. They don't make a T for EMT do they?

Unless someone points something else out, I kind of like that in my mind. Of course the biggest issue of picturing in my mind, there is a lot of room for it to rattle around.

Words dont work for this stuff.

555177d1287851192-surface-mount-electrical-igshop-076.jpg

You can see a box with a blank plate is a "T". Some of the pipes bend up to head to lights, some go up into the attic for other stuff... just to give you an idea.

If you run a ring of 1", you can run multiple receptacle circuits, plus larger cables for 220 stuff- compressor, saws, welders. The point is once the ring is installed, the added cost to add a 50Amp circuit to the other side of the room is whatever a few strand of #6 cost.

Hope that helps rattle stuff around!

Chewy13 · Dec 31, 2016

AndyA said:
The drilling then tapping is going to be a pain. The self-driller self-tapper screws will be fast and easy.

I'm assuming your perlins are 14ga or thicker. Anything thinner will likely strip the thread. I'd switch to drill and pop a rivet for thinner stuff.

If they're thick - possibly could you use beam clamp conduit hangars? They come in all different shapes and sizes. Just an idea.

walrus · Dec 31, 2016

Romex in a metal building?

jeff000 · Jan 2, 2017

dw1 said:
Stranded is easier to pull.

You know I see people say that all the time. But having pulled MILES and MILES of solid and stranded I would pull solid all day every day over stranded.

And I would pull T90 over RW90 all day long.

penright · Jan 2, 2017

ard said:
Words dont work for this stuff.
.....
Hope that helps rattle stuff around!

Unfortunately there is plenty of room for rattling.

The top, picture makes me what to finish off the walls. :lol_hitti

Do have a questions/point of clarification on the bottom picture. I see what looks like insulation at the top, then some corrugated panels. Up by the light the corrugated looks like it's under the purlin, then the middle looks like it on top of the purin. Then the EMT is ran in the C purlin channel behind the pole. Is the part of corrugated I am looking at the back of the outside skin or is it on the inside?
I see what you are talking about as T boxes. If I am right and the corrugated is on top of the purlin, then the bends where it had to leave the channel and meet the box is what I am talking about. I was wondering if there was a way of mounting the box on the purlin then have the conduit meet it from behind. I think it might be too tight of a bend. Just asking.

Here is a close up picture of my horizontal purin.

Side Note: When I was Previewing this post before I submitted it, I notice the screw holding the siding on. Those are going to be random up and down, I may just need to lay the EMT on top of it. Going down this path for a minute, let me ask for thoughts. Could I mount the box on top of the side (see picture)? @ishiboo mention, you do not want to weaken the sides, which in the horizontal would be top and bottom. Would a couple of #8 self drilling be too big of a hole? I would be worried about welding melting the insulation. Would that put too much leverage pushing/pulling plugs? Maybe make L by having a piece of horizontal plate to screw to the purlin and weld two plates vertically to screw the box to. This may be more work but it would keep all the connection behind the inside face of the purlin and if I ever did finish the walls, which I have no plans but who knows in 10 years....

sberry · Jan 2, 2017

It isn't going to hurt the steel to screw to it but forget all the MWBC **** for this garage and stay simple. You don't need to worry about balancing loads when the next circuit is a few ft from the panel. BTW, that is not a purlin, its a girt. It doesn't hold a lot and the sheet stiffens it, all the girt on the walls does is hold the sheet on the building. At the top the channel holds the roof line at the eve. It wont hurt a thing to put a raceway cover on that girt.

penright · Jan 2, 2017

walrus said:
Romex in a metal building?

The original question was using the C-Purlin as a chase. There was a lot of reasons that was a bad idea. There would not have been any "expose", but again from screws nicking, to the cover flashing being too wavy, just a bad idea. At least it get to reach the stupid idea virtually and not in reality

.

penright · Jan 2, 2017

jeff000 said:
And I would pull T90 over RW90 all day long.

What is T90/RW90.

sberry · Jan 2, 2017

Stick with as much standard stuff as you can. I do use a few handi boxes for dead ends and switches where I don't want someone to be able to fool with it or its simple duples outlets at the end of a pipe.
There is a lot of nonsense about wiring a building like this, did a couple and really made some mistakes and in hindsight would walk around and look at a couple if I could but first hook up a couple outlets and cords to get work wise.
I am a fanboy of some handi and some simple 4 inch combo boxes but care needs to be taken where it needs Gfci and a welder outlet as they need to be deep, new gfci have been changed and many do not fit in a shallow box.
I would bite the bullet and gfci the lights and plug them in.

penright · Jan 2, 2017

sberry said:
BTW, that is not a purlin, its a girt.

Thanks, my miss-use maybe where there is a lot of confusion in my question. I remember back in the day helping a buddy do some framing, when we braced off the rafters on cut roofs, I thought we called that purlin. At church when I needed some clips for hangers, they asked if it was C or Z purlin. That is why I was calling it that.

sberry said:
the MWBC **** for this garage and stay simple

I am kind of leaning that way. If it was not for GFCI, a MWBC would save on a wire, but I still am concerned that i would have GFCI issues. The only way I see it could work would be to use a GFCI outlet and let it protect downstream outlets. I know that GFCI works when it sees more current on the hot than the neutral, hench power is flowing through something else other than the design circuit. I don't know enough to feel comfortable that a MWBC sharing a neutral would work. I may not know enough to articulate my concerns.

sberry said:
It doesn't hold a lot and the sheet stiffens it, all the girt on the walls does is hold the sheet on the building.

I see how the sheet keeps the building from racking, and it would probably take a lot, but I could see if weakening a girt, with the right gust of wind, could fold in on you. To see the stress I talking about, look at an extremely unrealistic example. If you cut the sides and pushed on the middle, it could fold in. I am with you, I don't think two #8 holes would allow that.

sberry · Jan 2, 2017

penright said:
The original question was using the C-Purlin as a chase. There was a lot of reasons that was a bad idea. There would not have been any "expose", but again from screws nicking, to the cover flashing being too wavy, just a bad idea. At least it get to reach the stupid idea virtually and not in reality .

You know I hate to go here but I would consider getting some foam pieces and stabbing over screws and laying cables in to this in to the back of boxes with cable clamps and covering it with a sheet. I think the channel is a gift for simple diy and certainly acts as the ultimate raceway would be as good or better than some cable tray work I have see It would be super simple and instead of wiing a whole bunch you didn't need everywhere simply uncover it and add. Buy a box of blunt cover screws.

penright · Jan 2, 2017

sberry said:
I could but first hook up a couple outlets and cords to get work wise.

This was in my plan from the start. Because I don't have a plan.

What I mean, I want to get in and see where things fit first. I have to dump a bunch of tools and stuff. I need to build shelf for some storage. I need some light to work in the evenings. I planned on these be tempory till I get the "lay of the land" so to speak.

sberry said:
I would bite the bullet and gfci the lights and plug them in.

Interesting thought, what are the pros and cons?

sberry · Jan 2, 2017

Another thing, I got 14000 sq ft, all pipe, not a single piece of branch bigger than 3/4 and a lot of it 1/2. Most of it, its been a decade since I fundamentally added a switch loop I can recall and never need to come back and shove another fist full of big wires thru a pipe let alone a light circuit in a garage. The truth being I could pull 1/2 of it out today and wouldn't miss it a single time.
The big panel is nice and you can cluster a couple extra outlets around it for convenience, its cheap and safe but you do not need a whole bunch of branch circuits to every corner. Start right there before running a lot extra, do the short work and by then you will get a better feel for the branches. 90% of it be on 2 walls and around only 1 corner.

penright · Jan 2, 2017

sberry said:
90% of it be on 2 walls and around only 1 corner.

That is so true. It describes my old garage to a T.

I have a lot of respect for "farmboy". I will take one over a truck load of engineers. You know the song, a "country boy can survive" My old house was in the country, never had to pull a permit. New house has to survive city inspections.

sberry · Jan 2, 2017

In my case the ceilings are hi and 20 ft. I hang some fixtures at 14 and buy a box of beam clamps here, short 1/4 bolts etc and good selection of drillers. A 4x4 box across that channel with a couple screws wont weaken it and maybe even strengthen is. put them in opposing corners with 10 or 12. It would be a simple matter to add a connector to a box in any place.
You can tailor a fixture, do anything to it and hang the thing, move it, hang it with a new chain or simple pipe strap.

sberry · Jan 2, 2017

Ok, this would go bisexual. Get some angle iron and make a nice frame to bolt the panel to, bolt them as bars across the girt and eve strut, panel bolted to steel frame to steel building. A pipe out the top maybe but a piece of 3/4 out each side to a 4x4 where I could gfci and hook anything I wanted after that, screw a box to the channel at any point and heat to the ceiling with a piece or 2 of pipe.
I don't even use the switch by my door. Its as I walk thru on a desk lamp and use a night light. The switch wouldn't probably be legal as it is behind the door, I could move it but the tailor I have for it is way more ergonomic especially considering the traffic.

ard · Jan 2, 2017

First, those pics aren't mine- just stuff I found on the Internet.... Looks like GJ pictures actually. So I can't speak to why stuff was done.

As to your picture- you cannot curve EMT that is running IN that C channel into a box that would be mounted on the face. The minimum radius varies with pipe size, but even 1/2" needs 5,6 inches (as I recall)

Looking at your installs, I see the threads from the fasteners... Is that simple sheet metal? Not an insulated panel of something with 'meat'. I'm asking if you can screw an EMT clamp into the back of the Cchannel, and have 1/4" of thread beyond? If not, then you wouldn't be able to clamp them that way. There are other ways, I expect there are clips .... I'll google that in a second.

Edit- couldn't find it, but enter "b-line EMT purlin clip" into google and click on "image search"...will give you an idea of what is available. It's not a menards or homedepot buy, but could save some time. Or regular clams and attach it to the top of bottom part of the purlin (on the inside)....

The box could very nicely be attached with a self-drilling #12x1 sheet metal screw to they 1/2" friont facing flange, top and bottom. You would need to bend the EMT to make an. 'Offset' of looks like 2" or so. Like this:

There are a zillion you tube videos, pictures, websites, guides, how tos, etc, etc. You will F up a bunch at first, then you will have it dialed in.

IMO there is something satisfiung and robust about an exposed EMT job in a utility structure- shop, garage, mfg. Very satisfying. (But I'm odd)

sberry · Jan 3, 2017

You will not hurt the channel with a little screw. Those buildings are installed by amateur butchers all the time screwed all over, do not fall down. It's not that sensitive. Bend a challel cover and forget if it looks a little wavy, wtf?

sberry · Jan 3, 2017

Btw, you have a 6 for the welder, it runs from a 12 legal and even a 10 cable though. Yes, there are a lot of vids, a lot of ideas here but it often leads to more confusion than it solves.

sberry · Jan 3, 2017

Multi - wire has its place, big homes and shops with long runs and or heavy load. Here it would add to the cost and no savings to be had in a 30 ft building. just another level of complication and snot in boxes should and could be simple with many single circuits in them.
I did that **** early on, put everything I know or could find in a every one.

ishiboo · Jan 3, 2017

It adds to the cost but it gives you twice the capacity for less money than if you did it without a MWBC. There is no increase in complexity if you use a GFCI breaker. To each their own, in a shop if I have a choice of two 20A outlet circuits in the whole thing, or a single 20A outlet circuit... I'm going to pick the two!

checkthisout · Jan 3, 2017

Didn't read the thread carefully but this building has EMT written all over it.

I would not use Romex period.

Your first "project" in your shop will be learning to use a conduit bender or bite the bullet and hire an electrician to help you.

EMT and metal boxes along with the proper bracketry will look killer in that structure, not to mention the convenience conduit provides in adding circuits down the road.

jeff000 · Jan 3, 2017

penright said:
What is T90/RW90.

Single conductor insulation types. The two most common.

penright · Jan 4, 2017

What a priority, 32 degree F, dragging close to 175 pounds (guessing) cable, through nearly 200 feet of 1 1/2 conduit. Wife needs something outside, maybe it's too cold.

The green and black #10 spool is not for the service. While I punched through the brick, we put a 8 x 8 box on the outside. The 1 1/2 service conduit terminate there. Also I ran 3/4 conduit for a "future" portable generator inlet on the backside of the fence. The house panel is on the other side of the brick wall and there is a 2" between the panel and box. That way I can kill two birds with one hole. The neutral and ground are hard to see but they are off in the picture. Never pulled wire that big or that distance before. As I rolled it out across the yard, I was thinking this is not going to work. Started out with the electrician pulling and my feeding. Then it went to a couple of neighbor kids, one lifting, the other pulling for slack, that way I could push more. The finial 25 feet, neighbor kid dad pushing, me and the electrician pulling. Oh and I forgot to mention there were 4 90's. Would have had to have 5 except went back and recut the trench to give a big sweep. I remember asking the electrician why does code limit it to 4? He said, wait till we pull the wire, sometimes rules are just practical. I understand now.

sberry · Jan 4, 2017

ishiboo said:
It adds to the cost but it gives you twice the capacity for less money than if you did it without a MWBC. There is no increase in complexity if you use a GFCI breaker. To each their own, in a shop if I have a choice of two 20A outlet circuits in the whole thing, or a single 20A outlet circuit... I'm going to pick the two!

You may but is it needed and especially since this is a 30 ft building, big difference here than in a 3000 ft ranch or 60x60 with tall ceilings in a machine shop. The point is to have enough not to see how much one can jam in it. A guy doesn't have to go more than a few feet if he does find he needs to add something. He wont need 2 20A circuits at every door, only 2 will be used on occasion in the whole building. Most real power a few ft from the panel.
As I mentiomrd. zzzzzi been at this a while, I used to do all that stuff and don't anymore as I found when I look back havnt used really any of it and it wouldn't have made any difference or saved any money,,, although the pipe was a nice place to store some copper wire for decades.
Not such an issue in my shop as I wired a lot as I went but where I pre plan it all have half a dozen circuits in my storage never have had anything plugged in to them.
Those ae a couple first simple fix I put in when there was nothing, I don't use them much.

Running romex in C-Purlin.

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