500MCM in 3"

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arnettda

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I have done the math and I can put three 500's and a 2/0 in a 3" pipe. I would like a little advice from those who have done this alot, would I be better off going up one pipe size or not? My longest run is say 30' with 3-90's. Thank you .
 
IMO if the calculation allows it then it should be no problem. Are you pulling with a machine?
 
Was your math just for conduit fill, or did you also do a cable pulling tension calculation?
 
arnettda said:
I have done the math and I can put three 500's and a 2/0 in a 3" pipe. I would like a little advice from those who have done this alot, would I be better off going up one pipe size or not? My longest run is say 30' with 3-90's. Thank you .
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I have put four 500s and an EGC in 3" EMT, no problem as long as the person feeding does not let anything cross. If they do let them cross you will get stuck.

Here is what it looks like, you can see it is tight.

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Sometimes a larger conduit will allow the conductors to cross which can cause a jam. A smaller conduit will sometimes prevent conductors from crossing. Of course, if the conduit is so large that a cross doesn't cause a jam that is the easiest pull. There is a math formula for figuring out the likelyhood of jamming but I can't remember it.
 
Lube it up

Lube it up

Usually the guy that runs the conduit gets to (has to) pull the wire, that keeps everyone honest. I don't know what method you've got for attaching the cables to the pulling rope but make sure you've got a good mechanical (pulling) connection to each one of the wires, as earlier, keep the cables from crossing, let er rip.
 
mkgrady said:
Sometimes a larger conduit will allow the conductors to cross which can cause a jam. A smaller conduit will sometimes prevent conductors from crossing. Of course, if the conduit is so large that a cross doesn't cause a jam that is the easiest pull. There is a math formula for figuring out the likelyhood of jamming but I can't remember it.
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It's in IEEE 576-2000.
 
charlie b said:
Was your math just for conduit fill, or did you also do a cable pulling tension calculation?
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Charlie,
The pulling tension calculators that I have used do not use the conduit size in tension calculation. They only use it for wire fill and jam ratio.
 
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