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#52728 06/03/05 09:39 PM
Joined: Dec 2004
Posts: 1,064
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Anyone got a site, or link, that would provide wieghts for wiring, and conduit, and maybe the static loads for various size allthread?

I have to install (5) rows of 2" Emt with (3) 3/0 , (in each 2" pipe) on the top of the strut run, and (5) rows of 1 1/2" Emt with (3) #2 under that. The strut hangers are back to back 1 13/16" strut supported by (2) 3/8" malable beam clamps each using 3/8" allthread with appropriate sq strut washers and bolts. The hangers are spaced every 5' the lentgh of the run.

Any ideas where to find the total wieght and whether this is enough support?


Dnk.....

Joined: Feb 2003
Posts: 687
A
Member
Steel EMT:
1 1/2" EMT 11.6 lbs for 10'
2" EMT: 14.8 lbs for 10' http://www.alliedtube.com/electrical-raceways/conduit/electrical-metal-tubing.asp

Or you could use AL:
http://www.alliedtube.com/electrical-raceways/conduit/aluminum-grc-emt.asp

Steel strut:

Back to back 1 5/8 strut max load for 3' span 3,130 lbs
3.78 lbs for 1 piece of above strut 1' long


1 1/2 Steel EMT 5.8 lbs for 5' x 5 runs = 29 lbs

2" Steel EMT: 7.4 lbs for 5' x 5 runs = 37 lbs

Strut 1 5/8 x 3' x 2 runs = 23 lbs

Total Steel 89 lbs for 5' of above

Here is the copper wire. I can't say if it is the right wire or accurate but I'll try the numbers. http://www.allaboutcircuits.com/vol_5/chpt_3/1.html

15 #2 x 5'= 75' #2
15 3/0 x 5'= 75' 3/0

I figured 0.2 lbs /foot is #2 x 75'= 15 lbs
and 3/0 is 0.5 lbs / foot X 75'= 37.5 lbs

Total conductor weight is 52.5 lbs for 5'

Combined weight is 141.5 lbs for 5'
devide that by 2 threaded rods =71 lbs

Threaded rod specs: http://www.alliedtube.com/electrical-raceways/strut-channel/powerstrut.asp

1/4 threaded rod is rated for 240 lbs (3.4 times your load)
3/8 rod is rated at 610 lbs (8.6) times your load)
1/2 rod is 1,330 (18.8 times your load)

Keep in mind not all threaded rod my be to this spec. I would go with the 3/8 for more strength in side to side movement. Where a 1/4 should handle a strait down load it could fail under load when twisted or pushed sideways.

I didn't figure in hardware or fittings but it would not change much. Disclaimer :I'm not an engineer, just doing it as a puzzel.

You could also reduce some of your pipes to 1 1/4.

Tom

Joined: Dec 2004
Posts: 1,064
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Member
Tom, that's awesome.
Greatly appreciated.

I could use the 1 1/4" like you stated, but I have a couple of 100' of 1 1/2" left over from another job, and I wanted to get rid of it.

Thanks again....


Dnk.........

Joined: Aug 2001
Posts: 599
N
Member
Using a spred sheet a PM of mine put together and making a few assumptions it looks like you have plenty of rack capacity. Without more info I can't tell whether you meet seismic bracing requirements. (Also I am not sure what state you live in)
Conduit is always figured to maximum capacity regardless of what you are really putting in it and based on that here is what I come up with.
Total weight per foot-33.6
At your 5ft spacing:
Remaining trapeze capacity-93.7%
Remaining rod capacity-93.1%

Things you didn't say are trapeze width. For instance I assumed 24" wide. Changing that value to 84" reduces your trapeze capacity to 84.7%
Weather you have solid strut, slotted, round holes, or oval holes.
Rod length.
Weather you are using cable bracing or rigid bracing.

Edit:
Just to add another example if you had the same configuration using a single 1-5/8" strut instead of double strut at 84 " wide trapeze capacity drops to 14.1% and in danger of failure.
My above calcs were based on Power Strut PS 200 2T3 double strut. You mentioned two pieces of single strut back to back. That would change the values as well.

[This message has been edited by Nick (edited 06-04-2005).]

Joined: Dec 2004
Posts: 1,064
D
Member
Here's more info if you want it.

Strut lentgh 36"
Oval holed strut
lenth of allthread 12-14"

I don't understand the bracing Question you asked.

All supported by malable 3/8 beam clamps connected to I-beams off the cieling. Heavy duty ones.

Siesmic area Pa, SE area.

Appreciate the Help, sounds as if I have plenty of support for the load.

It is more of curiosity for me, as I find myself getting more and more involved with this type applications, so I better find a way to do calculations now.


Thanks again....


Dnk.......


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