Table 250.102(C)(1)

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david luchini said:
There is nothing to add. You have two conduits with 500kcmil ungrounded conductors in each. 500kcmil in the first conduit requires a 1/0 min grounded conductor. 500kcmil in the second conduit requires the same.
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infinity said:
It clearly says in the raceway.



If all of the parallel conductors where in a single wireway then you would add them, if they were in several separate raceways then you only need to use the size of the underground conductor in each raceway.
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I'm as lost as tkb on this.

The size of the grounded conductor in each raceway or cable shall be based
on the total circular mil area of the parallel ungrounded conductors
in the raceway
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There's two 500MCM conductors in each raceway totaling 1000MCM
 
ActionDave said:
I'm as lost as tkb on this.

The size of the grounded conductor in each raceway or cable shall be based
on the total circular mil area of the parallel ungrounded conductors
in the raceway.

There's two 500MCM conductors in each raceway totaling 1000MCM
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There are two raceways. In the first raceway there is one set of 500mcm. In the second raceway there is one set of 500mcm.

The total circular mil area in the first raceway is 500mcm...that requires a 1/0 minimum grounded conductor.

The total circular mil area in the second raceway is 500mcm...that also requires a 1/0 minimum grounded conductor.
 
david luchini said:
There are two raceways. In the first raceway there is one set of 500mcm. In the second raceway there is one set of 500mcm.

The total circular mil area in the first raceway is 500mcm...that requires a 1/0 minimum grounded conductor.

The total circular mil area in the second raceway is 500mcm...that also requires a 1/0 minimum grounded conductor.
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Are you saying that there are two raceways and in each raceway there is one 500mcm and one neutral?
 
Are you saying that Table 250.102(C)(1) applies to parallels in the same conduit and not separate conduits?
 
Since we've went round and round on this deal, I went back to read the original post to see if I'm missing something here.

In your first post, you mentioned you were trying to find the size of the grounded conductors for ungrounded conductors in parallel.

Our next step should of been to ask you, "are these paralleled conductors all in the same conduit or separate conduits?"
 
tkb said:
Are you saying that Table 250.102(C)(1) applies to parallels in the same conduit and not separate conduits?
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It applies to both, but it applies to the total area of the largest ungrounded conductor in each conduit separately.
 
Well the paralleling is just an exercise and i just wanted show the way but agreed that usually the 1/0 AWG will be the resolve in the OP's example.

Interesting enough and while not overly practical I have seen some exam questions in committees such as six (6) sets of 1000 kcmil where it would be 6,000,000 cm × 12.5% = 750,000 cm /6 = 125,000 cm so 1/0 would not work as it would be 2/0 AWG in each raceway.

But I am glad the CMP resulted in T250.102(C)(1) but that's just my opinion.

Paul W. Abernathy
Electrical Code Academy, Inc.
CMP #5 and #17
 
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