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#216019 09/07/15 08:47 PM
Joined: Jan 2004
Posts: 171
M
Merlin Offline OP
Member
Looking for some suggestions.....I am quoting a job to install a 2500 amp, 480/277V service. This will be feed from a pad mount transformer about 30 feet into a building. Obviously it will be parallel conductor fed. What combination would you all use? 750kcmil, 1000kcmil,.....any thoughts?

Merlin #216020 09/07/15 08:56 PM
Joined: Mar 2004
Posts: 947
T
twh Offline
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Aluminum. Then, all sizes are easy.

Merlin #216021 09/07/15 09:35 PM
Joined: Apr 2002
Posts: 7,279
Likes: 3
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Merlin:

Common is 6 sets of 600 KCMil Cu THHN/THWN in 4" PVC

You have to check the secondary 'window' of the pad mount xfr., as that limits the quantity of conduits you can install.


John
Joined: Jan 2004
Posts: 171
M
Merlin Offline OP
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Correct me if I'm wrong, but 6-600's would be
6 x 475 = 2850.
Derated for 4 conductors in conduit(480/277) at 80%
2850 x .8 = 2280.

Wouldn't it be 6x750kcmil?
6 x 535 = 3210
3210 x .8 = 2568

Merlin #216045 09/16/15 11:35 AM
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Merlin:
I stand corrected....I did not 'see' 2500 amps.



John
Merlin #216073 09/22/15 02:10 AM
Joined: Oct 2000
Posts: 2,721
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If this Installation is for Service Feeders (from a Poco Transformer to Service Equipment), you need to verify the requirements with the Service Planner before bidding this Project (or before commencing the actual work!)

If the Installation is on the LOAD side of the Service Disconnect, then (6) 4" Ducts with 4-750MCM CU. per duct is sufficient... if NO Equipment Grounding Conductors are installed!

If an EGC is to be installed, that will be a minimum of (1) 350MCM CU. per duct, so now the Ducts would be 5" (???)
dunno

--Scott (EE)


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

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