Feeder Calculation

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shockrocker68

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what is the proper feeder for a 3p4w 1200A breaker?, I have seen several responses saying Parallel 500kcmils conductors are not sufficient
 
Re: Feeder Calculation

Are you asking what conductors, in parallel, have an ampacity of 1200 Amps?
 
Re: Feeder Calculation

3 sets of 500kcmil is good for 1140 amps. 240.4(C) does not permit rounding up once the device is above 800 amps. You could use 3 sets of 600kcmil or 4 sets of 350 kcmils.
One of the reasons they do not permit rounding up for larger than 800 amps is, the heat of the conductor is relative to the square of the current.

Pierre
 
Re: Feeder Calculation

I have also heard that the OCPD Is only rated up to 80% of its actual FLC rating, Please shed some light on this issue.
 
Re: Feeder Calculation

This 1200 Amp breaker is for the panel.

What is the size of overcurrent device ahead of the feeder?
 
Re: Feeder Calculation

Shock
Your breaker is rated at 1200 amps for noncontinuous load. IF all the load was continuous
then you would have keep the load to 80% of the rating.

[ March 28, 2004, 10:13 PM: Message edited by: bob ]
 
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