parallel feeders in same conduit

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U-tube-bender

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Hi All! New to the site but not to the trade. I'm looking to upgrade a 300 amp service to 600 amps via parallel feeders. We currently have 4- 350's in 1 - 4" conduit. I wanted to install 4 more in the same conduit but the engineer I talked to at the utlity company said no. The code book allows 8- 350's in 1 conduit. why wouldn't i be able to parallel throught the same conduit? Or can I? :confused:
 
Rule 1: POCO can make there own rules.
In regard to the NEC, what is your calculated load ? You won't have 600 amps worth of conductor ampacity.
 
augie47 said:
Rule 1: POCO can make there own rules.
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To a degree, yes. However, their's in this regard is usually less conservative than the NEC.

In regard to the NEC, what is your calculated load ? You won't have 600 amps worth of conductor ampacity.
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Well that depends on several system factors which have yet to be divulged... but you are likely correct. In addition to calculated load, we need to know the entire configuration of the main to say with absolute certainty.
 
For the 8 conductors (6 CCC's) in one raceway you'll have a derating issue. 350 kcmil Cu @ 90 degrees C = 350 amps,

2 * 350 * 80% = 560 amps ampacity.
 
jrannis said:
Next OCP size up is 600amps. Looks like its good.
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possibly, but as Smart$ pointed out, we don't have a load calculation. It might exceed 560 and as Pierre points out, I'm assuming Cu.
 
Thankyou to all who replied. The answer is that it is copper and the utility company will not allow it. I must do a separate conduit for the additional 4- 350's. And you're right on with the derating of 80%. Eventhough my calculated load is less than 560, as augie47 stated, they make their own rules. they were even trying to get me to run an additional empty 4" conduit, but i won that fight! This was PSE&G in south jersey.
 
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