Help mounting 3/4" conduit to hollow wall

Roothawg · Mar 9, 2020

I bought a new compressor and started to lay out my conduit this weekend. The problem is, I have a steel building and there is no structure where I am wanting to mount it. I covered the insulation with galvanized corrugated sheet material, bu the span is too far apart. I need to mount a J box and support about 8' of conduit.

Do they make a wall hanger similar to plumbers strap, but more substantial? Like a track of some sort?

I found this, but I am not 100% sure on how to use it. I THINK I know, but.....

https://www.grainger.com/product/GRAINGER-APPROVED-Slotted-Standard-1-5-8-x-1-45YV29

Thanks,

Root

mike93lx · Mar 9, 2020

Unistrut, what you linked.

You should be able to get 10' lengths. Lookup their catalog, you'll see hundreds of options for mounts

Roothawg · Mar 9, 2020

I assume it is designed to mount vertically?

rlitman · Mar 9, 2020

Roothawg said:
I assume it is designed to mount vertically?

You use the holes to bolt it to your structure, perpendicular to the pipe run, and then use special pipe clamps to secure the pipes to it.

BillK · Mar 9, 2020

How about a picture of where you want to mount it. The pipe shouldnt have to be supported along its entire length. I am thinking one support at each end and one in the middle. I might be wrong but that price for Unistrut looks awful high too. Check with a local electric supply house first.

BukitCase · Mar 9, 2020

Agree with Bill; Grainger is where you buy when you're using somebody ELSE's $$$ - heres same size gold colored unistrut, same price for TEN foot piece instead of 4'

https://www.homedepot.com/p/Superst...Channel-Gold-Galvanized-ZA1200HS-10/100125003

... Steve

rlitman · Mar 9, 2020

BillK said:
How about a picture of where you want to mount it. The pipe shouldnt have to be supported along its entire length. I am thinking one support at each end and one in the middle. I might be wrong but that price for Unistrut looks awful high too. Check with a local electric supply house first.

HD carries it. I just paid $20 for a 10 foot galvanized stick of the thin (3/4" depth) galvanized strut channel. The yellow stuff is a little cheaper, and the 1-5/8" tall is a little more expensive.

It cuts easily. I brought a hacksaw with me to the store and cut the 66" piece I needed on the shopping cart to fit it all in my car.

Roothawg · Mar 9, 2020

Thanks. I found some at Lowe's in my home town way cheaper.

One end goes into the fuse box, the other will be supported on the end with the J box. I don't even need the J box really. I bought a 6' conduit whip but I don't think I want to cut and tie the ends together. I like the idea on no breaks in the line. The wire from the box is long enough to reach the compressor in one continuous run, so I just need something to make the transition from the PVC flexible conduit to the end of my EMT conduit.

I don't have any pics. I'll have to snap some tonight, if I get time.

Honestly, I need the shortest stuff they make. It makes it easier to get under the conduit. I also have some previously mounted 1/2" zinc water line I use for shop air. It needs supporting as well. I'll try and capture all of it with 2 sticks. If I am lucky I can cut one in half and get what I need. Just have to measure tonight to make sure.

Bopbop · Mar 9, 2020

Search in the Grainger website site for a B-Line conduit clamp which is listed as their item #4RHZA, model number BL1410. I used these to mount my aluminum airlines to the sheet metal panels in my shop. Home depot also keeps these in stock in their stores.
The unistrut works real good but cost more. Around here home depot also stocks it and the clamps

Roothawg · Mar 9, 2020

Thanks guys. Now that I know what it's called, it makes it easier to search.

mike93lx · Mar 9, 2020

Superstrut is another brand, might help in your search. I've bought it at lowe's

rlitman · Mar 9, 2020

mike93lx said:
Superstrut is another brand, might help in your search. I've bought it at lowe's

Superstrut, Unistrut, Kindorf. There are a number of strut channels out there. They're not all 100% compatible FYI.

cybrdyke · Mar 9, 2020

Sammy's
https://www.minerallac.com/products/fasteners/hangers/sammys/?product=61202
CD

sberry · Mar 9, 2020

Conduit clip and a sheet metal lap screw.

Terry D · Mar 9, 2020

One hole straps for EMT or Minerallacs ( also called minnies ). Minnies holds the conduit 1/2 inch off surface, no need to bend a box offset in the conduit to bring it in the box. If you use a one hole strap, you will have to bend a 1/2 inch box offset to bring it in the box. I personally like one hole straps and box offsets. Use sheet metal screws to attach everything. Unistrut would be overkill for that small of conduit and that short off run, just my opinion.

sberry · Mar 9, 2020

Too simple,,,, ha

Jim greengo · Mar 9, 2020

Self tappers

Bert_ · Mar 9, 2020

Jim greengo said:
Self tappers

Don't use self tappers on sheet metal. You need a pointed sheet metal screw or they will strip.

sberry · Mar 9, 2020

Sheet metal screws are self tapping,, I know we are talking about drillers. A lap screw, I forget the tech name but it has a big barrel designed for sheet to sheet. Put them in laps where it's double thickness. Even use a 2 hole on the end, even common screws 10 or better works. Can even do this 1/2 pipe,,, believe it or not.

Terry D · Mar 9, 2020

Bert_ said:
Don't use self tappers on sheet metal. You need a pointed sheet metal screw or they will strip.

I agree on this, self tappers make to big of hole on sheet metal. use regular sheet metal screws

sberry · Mar 9, 2020

Self drilling is different than self tapping. But agree a common sheet metal screw will work.

Bert_ · Mar 9, 2020

sberry said:
Self drilling is different than self tapping. But agree a common sheet metal screw will work.

You're right. The terminology is often interchanged but not the same. Self drilling is the wrong choice. A sheet metal screw is fine.

TRWham · Mar 9, 2020

Agree that, irrespective of fastener type, strut is excessive here. For 8’ of EMT just use straps and drive on down the road.

teamextreme · Mar 10, 2020

Roothawg said:
One end goes into the fuse box, the other will be supported on the end with the J box. I don't even need the J box really. I bought a 6' conduit whip but I don't think I want to cut and tie the ends together. I like the idea on no breaks in the line. The wire from the box is long enough to reach the compressor in one continuous run, so I just need something to make the transition from the PVC flexible conduit to the end of my EMT conduit.

You guys are in the weeds about fasteners. I'm more concerned about this convoluted description of the conduit run. Can you post some pics or give a better description? This sounds all kinds of jacked up.
Are you running a continuous conduit from panel (not a fusebox) to receptacle box?
Are you using multiple types of conduit?
Is the conduit just short sleeves for protection of romex?
What kind of wire are you pulling?
If you are using PVC, are you running a ground wire?

Jim greengo · Mar 10, 2020

Bert_ said:
Don't use self tappers on sheet metal. You need a pointed sheet metal screw or they will strip.

The thread is what holds it in the sheetmetal,the point of the self tapper just starts the hole is all.
It's pretty tough to start a sheet metal into the heavy gauge tin used inside buildings without a pilot hole or a self tapper. :beer:

Jim greengo · Mar 10, 2020

TRWham said:
Agree that, irrespective of fastener type, strut is excessive here. For 8’ of EMT just use straps and drive on down the road.

Terry D · Mar 10, 2020

teamextreme said:
You guys are in the weeds about fasteners. I'm more concerned about this convoluted description of the conduit run. Can you post some pics or give a better description? This sounds all kinds of jacked up.
Are you running a continuous conduit from panel (not a fusebox) to receptacle box?
Are you using multiple types of conduit?
Is the conduit just short sleeves for protection of romex?
What kind of wire are you pulling?
If you are using PVC, are you running a ground wire?

Sounds like he is running EMT from the panel to a J-Box and then using a sealtite whip to go from there to the compressor. I hope he is using THWN and not Romex in the conduit. As long as the panel is only 8 ft away and in sight, the circuit breaker would serve as the disconnect

mike93lx · Mar 10, 2020

Terry D said:
Sounds like he is running EMT from the panel to a J-Box and then using a sealtite whip to go from there to the compressor. I hope he is using THWN and not Romex in the conduit. As long as the panel is only 8 ft away and in sight, the circuit breaker would serve as the disconnect

Romex is fine in conduit. Thhn is easier, no question. But if it is indoors and not a wet location romex is kosher

sberry · Mar 10, 2020

Common screws will go thru sheet. The main reason for drillers is drilling to structural steel.

nadogail · Mar 10, 2020

No matter what any one recommends, someone else will say that is the wrong choice.

Help mounting 3/4" conduit to hollow wall

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