Ampacity Reduction

W

wwhitney

Senior Member
Location
Berkeley, CA
Occupation
Retired
bkg73123 said:
In this article by Mike Holt why aren't the primary conductors ampacity reduced by 20% as well as the secondary conductors?
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The secondary conductors include a neutral, and the rather old article includes the assumption that a majority of the loads supplied are non-linear, so that the neutral counts as a CCC. [I believe that in practice these days, that is almost never warranted, so you'd only have 3 secondary CCCs.] With 4 CCCs on the secondary, you need an 80% ampacity adjustment factor.

The transformer primary is delta, so there are just 3 line conductors run to it, no neutral. With only 3 CCCs, there's no need to apply any ampacity adjustment factor.

Cheers, Wayne
 
B

bkg73123

Member
Location
TX
Occupation
Estimator
wwhitney said:
The secondary conductors include a neutral, and the rather old article includes the assumption that a majority of the loads supplied are non-linear, so that the neutral counts as a CCC. [I believe that in practice these days, that is almost never warranted, so you'd only have 3 secondary CCCs.] With 4 CCCs on the secondary, you need an 80% ampacity adjustment factor.

The transformer primary is delta, so there are just 3 line conductors run to it, no neutral. With only 3 CCCs, there's no need to apply any ampacity adjustment factor.

Cheers, Wayne
Click to expand...
So according to current code requirements 600kcmil conductors would work, since neutral not considered ccc, correct?
 
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