Feeder Grounded Conductors

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augie47

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Location
Tennessee
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State Electrical Inspector (Retired)
(2215.2(AP)(2) Grounded Conductor.

The size of the feeder circuit grounded conductor shall not be smaller than that required by 250.122, except that 250.122(F) shall not apply where grounded conductors are run in parallel

I'm having a difficult time understanding the portion in RED.
 

luckylerado

Senior Member
(F) alows for a single grounding conductor to be installed when parallel sets are installed in a single raceway.

So if you are installing parallel phase conductors in a single raceway you must also parallel the grounded conductor.
 

jumper

Senior Member
I think Infinity has the answer, he wrote:

This is the way I'm reading the requirement:

A grounded conductor is required to be large enough to carry a line to neutral fault therefore it's required to at least as large as the minimum size grounding conductor listed in 250.122. But grounding conductors when run in parallel must be sized according to the OCPD ahead of the feeder, that rule, 250.122(F), does not apply to the grounded conductor.

For example a 2000 amp feeder would require a 250 kcmil grounding conductor in each raceway based on the 2000 amp OCPD. The sum of all the grounded condcutors run in parallel in each raceway is only required to be equal to the minimum size of 250 kcmil.

This the thread:

http://forums.mikeholt.com/showthread.php?t=117864&p=1101483#post1101483
 
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