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Old 04-12-2019, 10:19 PM   #1
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Default Code for dropping conduit from the ceiling in a factory?

Hello all,

I am mounting an outlet box to a 42" tall 4x4 steel post thats anchored to the ground. I have to bring 3/4" EMT down to it from the ceiling, about 20ft total. There is nothing around to anchor the conduit to. Am I required to run a piece of unistrut up from the post and clamp the conduit to it? If so, how high do I have to run it?
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Old 04-12-2019, 10:40 PM   #2
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The usual drill is to jump to 20' sticks of IMC, RMC. ( 20' stuff is special order but if you can wait for it to come in may be dreamy for you.)

I'd forget EMT in this situation. You're in a factory.

Usually you'll get a pass on conduit support IF you properly anchor it top-side and at the floor.

Many guys will anchor the run in RMC -- a short stub up -- set an FS box -- then take the rest of the run all the way up in IMC. The bottom RMC never gets any wire. It's strictly for support to some ideal height.

Other guys go with a cord drop, with strain relief and all the rest. That's a super popular option.

If necessary, toss in a foot-rig of strut.

3,000 miles away -- I really can't see your factory floor.
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Old 04-12-2019, 10:58 PM   #3
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Originally Posted by telsa View Post
The usual drill is to jump to 20' sticks of IMC, RMC. ( 20' stuff is special order but if you can wait for it to come in may be dreamy for you.)

I'd forget EMT in this situation. You're in a factory.

Usually you'll get a pass on conduit support IF you properly anchor it top-side and at the floor.

Many guys will anchor the run in RMC -- a short stub up -- set an FS box -- then take the rest of the run all the way up in IMC. The bottom RMC never gets any wire. It's strictly for support to some ideal height.

Other guys go with a cord drop, with strain relief and all the rest. That's a super popular option.

If necessary, toss in a foot-rig of strut.

3,000 miles away -- I really can't see your factory floor.
Unfortunately all they give us is EMT, and they wont special order anything for just a 2 gang outlet box.

I think a cord drop is out of the question, since there are pallets and product being moved around in the vicinity and they wouldnt want anything that can catch on a hanging cord.

As it is right now, Im being told attach a stick of unistrut to the post and clamp the EMT to that, then attach the box to the unistrut. I just wanted to be sure there isnt a glaring problem with this method.
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Old 04-12-2019, 11:06 PM   #4
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Quote:
Originally Posted by benwinch07 View Post
Hello all,

I am mounting an outlet box to a 42" tall 4x4 steel post thats anchored to the ground. I have to bring 3/4" EMT down to it from the ceiling, about 20ft total. There is nothing around to anchor the conduit to. Am I required to run a piece of unistrut up from the post and clamp the conduit to it? If so, how high do I have to run it?
Are you saying the ceiling is 20' high, or it's 20' of conduit from the box to the ceiling?

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Old 04-12-2019, 11:10 PM   #5
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Are you saying the ceiling is 20' high, or it's 20' of conduit from the box to the ceiling?

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Just shy of 20' from the box to the ceiling
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Old 04-12-2019, 11:43 PM   #6
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You don't do this very much, I can see.

Just because it's a cord drop does NOT mean that the box is free to swing in the breeze.

Take a gander at the back threads on this EXACT topic here at ET.

It's been brought up at LEAST a dozen times.

Beaten to death, it has been.
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Old 04-12-2019, 11:56 PM   #7
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I understand that a cord drop isn’t free swinging, but the plant engineer has specified no cord drops on this, but rather EMT. I’m mostly experienced with running EMT along existing structures that it can be anchored to. I’m just wondering if using the unistrut is approved in this free standing situation.
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Old 04-13-2019, 02:26 AM   #8
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Quote:
Originally Posted by benwinch07 View Post
As it is right now, Im being told attach a stick of unistrut to the post and clamp the EMT to that, then attach the box to the unistrut. I just wanted to be sure there isnt a glaring problem with this method.
The glaring problem is you have to secure the EMT every 10' and you are going 20'. You can span 20' vertically between supports with RMC but not EMT.

If you are going to run EMT, you have to run some structure to that 10' point. You could run back to back strut from the floor to the trusess, that would be fine, 50' of strut, strut fittings, some nuts and bolts, some time with the wrenches and sockets and portaband and hammerdrill and a few anchors, and

they'll really wish they just bought you RMC.
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Old 04-13-2019, 02:27 AM   #9
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You can get 20' lengths of strut pretty readily, you could fasten that between the top of the post and the ceiling, and run your pipe on that.

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Old 04-13-2019, 02:55 AM   #10
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Thank you guys!! I appreciate all of the input!!
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Old 04-13-2019, 09:33 AM   #11
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Quote:
Originally Posted by benwinch07 View Post
Unfortunately all they give us is EMT, and they wont special order anything for just a 2 gang outlet box.

As it is right now, Im being told attach a stick of unistrut to the post and clamp the EMT to that, then attach the box to the unistrut. I just wanted to be sure there isnt a glaring problem with this method.
This is what you should do,:
Im being told attach a stick of unistrut to the post and clamp the EMT to that, then attach the box to the unistrut.

and find a way to do a nice job with it
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Old 04-13-2019, 08:52 PM   #12
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20+ feet of unsupported emt? No thanks. Get 2 or 3 sticks of GRC, supported at least once above the outlet box and twice in the ceiling.
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Old 04-13-2019, 09:07 PM   #13
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7Meters up?

humm with EMT that is not the best choice at all unless you got 8 meter strut or 20 footer if you can get it. but for myself I would just run rigid conduit and be done with it. less thing can go wrong with it. especially with flying dolts like to hit the conducts.,,

But some factories I have see that arrangement from time to time as long it dont hit anything that set up is ok.

and oui the strut can be used for support for emt conduit but make sure you get it secured good.
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Old 04-13-2019, 10:04 PM   #14
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The OP is battling management over materials and some supervision over methods.
I would put a 3/4" floor flange on the deck. Put a 3/4" tee, pipe up to the ceiling.
Use a 3 hole box and a close nipple out of the box. 6" nipples out of the top and bottom. Back to back mini straps between the nipples and the vertical 3/4
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Old 04-14-2019, 05:46 AM   #15
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You can get 20' strut but it is a bit of a pain since it will take a couple days to come in and you'll have to have it delivered, and nobody is going to be thrilled to deliver your one 20' stick.

If you double up regular 10 strut back to back staggered - two 10' pieces on one side, 5' + 10' + 5' on the other side - one cut, eight nuts and bolts, and you're done - it's probably faster.

However I'd like to change this answer, you can buy 2x4's and spikes for much less and you'll be well under $100 of butchered wood.
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Old 04-14-2019, 05:57 AM   #16
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Relocate the equipment to be served by the "outlet box" against a wall or a ceiling to floor pier.
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Old 04-14-2019, 05:41 PM   #17
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Quote:
Originally Posted by splatz View Post
You can get 20' strut but it is a bit of a pain since it will take a couple days to come in and you'll have to have it delivered, and nobody is going to be thrilled to deliver your one 20' stick.

If you double up regular 10 strut back to back staggered - two 10' pieces on one side, 5' + 10' + 5' on the other side - one cut, eight nuts and bolts, and you're done - it's probably faster.

However I'd like to change this answer, you can buy 2x4's and spikes for much less and you'll be well under $100 of butchered wood.
My favourite fastener supply place has 20' strut in stock, and free next day delivery with no minimum order. I would still throw some other stuff on the order just because.

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