Dropping pipe from a 40' ceiling?

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Bloose

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We are starting to look at installing some small machines in a manufacturing building. The machines will essentially be in the middle of a large open area and we need to get power to them. We will likely be dropping 480 in 1/2" or 3/4 pipe from the ceiling. Does any one have suggestions for supporting the pipe between the ceiling and floor? These are small machines so I don't think a large 40' posts at each location are going to work. In the past we've used 20' pieces of Unistrut nailed to the floor. In those cases though the ceiling was only 25' tall so there was no problem clamping the pipe at 10' intervals.


TIA,
B-loose
 
I would suggest using IMC or RMC type conduit for the drops. You are permitted to support the conduit at intervals not exceeding 20 feet if the conduit is made up with threaded couplings and the conduit is supported at the top and the bottom of the riser.

Take a look at 342.30(B)(3) and 344.30(B)(3) for IMC and RMC.

Chris
 
barbeer said:
With conduit sizes that small, why not think of flexible cord or cable with cord and plug connections?
Click to expand...

That is exactly the way I've done it in auto shops for ther car lifts...don't forget the strain relief connectors...and twist lock plugs.
 
IMO it wold be a violation to use cord for this.

The fact that running pipe is more difficult is not one the listed permissions in 400.7
 
Depending upon the type of machine to be installed it could possibly meet

400.7(6) Connection of utilization equipment to facilitate frequent interchange. Or

400.7(8) Appliances where the fastening means & mechanical connections are specifically designed to permit ready removal for maintenance and repair, and the appliance is intended or identified for flexible cord connection.

-Ed
 
This could turn out to be an interesting thread.

I agree with the use of cord and not permitting the use of cord...;) :grin:
I am sure you love to hear that. One screwed up inspector....


Cords would be permitted to be installed if they are installed as "pendants". But, one has to be careful of the environment and whether the AHJ will deem the area subject to physical damage. Also does your plant permit cords for drops.

Otherwise, as has been mentioned, you can follow the requirements of 344.30(B)(3).
 
ed downey said:
Depending upon the type of machine to be installed it could possibly meet

400.7(6) Connection of utilization equipment to facilitate frequent interchange. Or

400.7(8) Appliances where the fastening means & mechanical connections are specifically designed to permit ready removal for maintenance and repair, and the appliance is intended or identified for flexible cord connection.

-Ed
Click to expand...

That is true. But, these machines do not fall into this catagory. They are bolted down and they are repaired in place. So it's not an option in this case.

I do like the RMC and IMC idea, I didn't think of that. I will have to measure and see if that will help us out.

Thanks,
B-loose
 
Pierre C Belarge said:
This could turn out to be an interesting thread.

I agree with the use of cord and not permitting the use of cord...;) :grin:
I am sure you love to hear that. One screwed up inspector....


Cords would be permitted to be installed if they are installed as "pendants". But, one has to be careful of the environment and whether the AHJ will deem the area subject to physical damage. Also does your plant permit cords for drops.

Otherwise, as has been mentioned, you can follow the requirements of 344.30(B)(3).
Click to expand...

We do not ever run cord drops here. It is very rare for us to have cord connected equiptment but if we do we would drop pipe from the ceiling to an outlet or outlet/disconnect and keep the cord use as low as possible. In a very few cases we could by code use cord drops but in most we cannot anyway. But on the old side of the plant our ceilings are about 20' lower than the new side.

In a previous plant I was in I was told to use cord drops to supply power to some lathes and mills. I refused to do it unless the AHJ OK'ed it. I was told every place the engineer came from that's how they did it, every place he had ever seen was like that, etc. I told him I didn't do those installs so I didn't care what they did, if he got the AHJ's blessing I was fine with it but otherwise, no. The next day he said "hard pipe it". :)

So I guess I'm saying that even though it is common to see it that way there are many cases where I think it shouldn't be.

Thanks,
B-loose
 
Use two 20' pieces of 1" galvanized pipe with deck flanges for support and back to back minerac straps for your conduit.
 
How many of these things do you have? What about chopping the floor and running the conduit up a wall?
 
Bloose said:
We are starting to look at installing some small machines in a manufacturing building. The machines will essentially be in the middle of a large open area and we need to get power to them. We will likely be dropping 480 in 1/2" or 3/4 pipe from the ceiling. Does any one have suggestions for supporting the pipe between the ceiling and floor? These are small machines so I don't think a large 40' posts at each location are going to work. In the past we've used 20' pieces of Unistrut nailed to the floor. In those cases though the ceiling was only 25' tall so there was no problem clamping the pipe at 10' intervals.
TIA,
B-loose
Click to expand...

It seems like a perfect application for a modular busway with CB taps. Suspend it from the ceiling with 3/4" threaded rods at about 10' above floor level and use plug and cord to connect if flexibility is needed or just conduit with floorplate support.

GE Spectra
Square D I-Line II Busway,

Etc.
 
chris kennedy said:
I've never heard this. You mean like a cable tray?
Click to expand...

No, not like cable tray 392, like a raceway 384. :smile:

You can get strut with KOs instead of slots on the back and you add snap on covers to the front to make it enclosed.
 
infinity said:
But how would you support it? Can that be run 40' without support?
Click to expand...

When used as a raceway it must have a support every 10'

But you could run 40' of empty strut then secure a raceway to that.
 
iwire said:
But you could run 40' of empty strut then secure a raceway to that.
Click to expand...


That I agree with. But trying to kill two birds with one stone, (using the strut as the raceway and the support) brings you right back to the problem you would have with conduit. The support issue.
 
I have done this before by dropping allthread down to unistrut. Then come off the first piece of strut with more allthread and another piece of strut. I would still recommend using rmc or imc.
Then screw mineral lite straps to the unistrut. But when I did it we had more than one drop so it worked really well.
 
B-loose,

Any other systems needed for the equipment, air, water, etc. , just thinking

of a group type drop.

second idea, have you ever made, what we call, strut telephone poles??

What they are: back to back double strut, double strut floor plate anchored

with drop-ins, 10,15, or 20 ft. high what ever the situation allows, put a 24"

"T" on the top using "L" brackets.

Bring your home runs down a column to the hieght of the strut poles, place

the poles out of the way best you can, run pipe on top and drop down to

the equipment.
 
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