1200 amp feeder

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JOSEELECTRICAL

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Location
new york
Occupation
electrician
I have a real problem on a job site and I need to know how you would solve it using the most inexpensive option



  • We need to feed a 1200AMP service switch from a Con-Ed box underground.
  • The service switch has only (4) 500MCM lugs for each phase
  • The conduit run is only around 30’ so no need to calculate voltage drop


Question

  1. Need to know how many conduits from end box to SW
  2. Size of conduit
  3. Size of wire
  4. Size of EGC (Equipment ground wire)
 
4 conduits
3" PVC or RMC
4-400 kcmil in each
No EGC required since this is not a feeder
 
JOSEELECTRICAL said:
4 conduits or just 1 4” conduit?
Click to expand...
JOSEELECTRICAL said:
We running PVC between the gal 90
So you definitely ECG
250.122
We need Parallel the sets how many?
Why 400mcm ?
What the smallest wire we can use if you ran 4 sets that adds up to 1200amps
Click to expand...
See post #2.

There is no EGC on the line side of the service disconnect. If you're using a metallic raceway it gets bonded to the neutral.
 
infinity said:
See post #2.

There is no EGC on the line side of the service disconnect. If you're using a metallic raceway it gets bonded to the neutral.
Click to expand...
we need to parallel the set how many
why 400mcm
what is the smallest wire we can use if you ran 4 sets that adds up to 1200 amps
 
JOSEELECTRICAL said:
we need to parallel the set how many
why 400mcm
what is the smallest wire we can use if you ran 4 sets that adds up to 1200 amps
Click to expand...
The number of sets is 4 which is right there in post #2.

Regarding conductor ampacity do you have access to the NEC? Look at T310.15(B)(16).

400 kcmil=335 amps * 4=1340 amps.

You can also use 350 kcmil but the 400's might be more readily available. So to answer your question 350's would be the smallest conductors if using 4 sets in separate raceways.

350 kcmil=310 amps * 4=1240 amps.
 
infinity said:
The number of sets is 4 which is right there in post #2.

Regarding conductor ampacity do you have access to the NEC? Look at T310.15(B)(16).

400 kcmil=335 amps * 4=1340 amps.

You can also use 350 kcmil but the 400's might be more readily available. So to answer your question 350's would be the smallest conductors if using 4 sets in separate raceways.

350 kcmil=310 amps * 4=1240 amps.
Click to expand...
so i need how many parallest set i need
 
JOSEELECTRICAL said:
thank you infinity for taking your time to help me
Click to expand...
Glad to help. There are many different ways to do this. One guy might pull multiple sets in each raceway but then you need to derate for the CCC's, etc. Some guys like big conductors some like lots of smaller conductors. Ask three people and you'll probably get three different opinions. :)
 
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