Running multiple grounded conductors in parallel

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aelectricalman

aelectricalman

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Location
KY
We have 5 -4 in rigid conduits. 2000A. We ran in each 4-500kcmil and 1#3 awg to each conduit. The combination of tjhe 5 #3 is more than enough. The question is, can they be parrelleled like the ungroinded conductors
 
P

petersonra

Senior Member
Location
Northern illinois
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engineer
I think the answer in general is yes, how ever the grounded conductor can't be smaller than the EGC. I am not sure that you can count the total size of the paralleled grounded conductors as the grounded conductor size or not.
 
david luchini

david luchini

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I may be misunderstanding the post, but he seems to be asking about the EGC, not the grounded conductor.

aelectricalman said:
We ran in each 4-500kcmil
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3 phase and one neutral conductors?

aelectricalman said:
and 1#3 awg to each conduit. The combination of tjhe 5 #3 is more than enough.
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5*52620cm (#3) = 263,100cm. Minimum size of egc for 2000A = 250,000cm, so 5#3 is "more than enough"?

As Dennis notes, the EGC should be 250mcm in each conduit.
 
Dennis Alwon

Dennis Alwon

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david luchini said:
I may be misunderstanding the post, but he seems to be asking about the EGC, not the grounded conductor.



3 phase and one neutral conductors?



5*52620cm (#3) = 263,100cm. Minimum size of egc for 2000A = 250,000cm, so 5#3 is "more than enough"?

As Dennis notes, the EGC should be 250mcm in each conduit.
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My original post was about the egc then I saw Bob's post and I re-read the OP and saw he wrote neutral. I changed my post-- maybe he did mean egc as that seems to be the question everyone has.

250.122(F)
 
Smart $

Smart $

Esteemed Member
Location
Ohio
aelectricalman said:
I tjought it had to be sized for 2000 A. 250 in one conduot or spaced among all the conduits as #3 in 5 conduits.
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The code section is...

250.122 said:
(F) Conductors in Parallel. Where conductors are installed
in parallel in multiple raceways or cables as permitted in
310.10(H), the equipment grounding conductors, where used,
shall be installed in parallel in each raceway or cable. Where
conductors are installed in parallel in the same raceway, cable,
or cable tray as permitted in 310.10(H), a single equipment
grounding conductor shall be permitted. Equipment grounding
conductors installed in cable tray shall meet the minimum
requirements of 392.10(B)(1)(c).
Each equipment grounding conductor shall be sized in
compliance with 250.122.
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Smart $

Smart $

Esteemed Member
Location
Ohio
curt swartz said:
Your 500's are also undersized for a 2000 amp feeder. 380 amps * 5 = 1900 amps.
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Typically so... but not in all instances, as termination temperature limitations at 75?C is overemphasized. IMO, there are instances where 90?C termination temperatures can be used, but other than transition junction boxes, pretty much limited to busbar-type terminations with 90?C or better rated compression lugs on wire ends.
 
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