Generator Conductor Sizing

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big john

Senior Member
Location
Portland, ME
Just want some opinions on this: If the feeder breaker is set to the full load capacity of the generator, would that qualify for the 445.13 Exception that allows me to size conductors at 100% of the generator rating?

Seems like "yes," but....

-John
 
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curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
Does the generator have built in circuit breaker? If so and you are asking about the conductors after this circuit breaker 445.13 doesn?t apply.
 
cadpoint

cadpoint

Senior Member
Location
Durham, NC
Just want some opinions on this: If the feeder breaker is set to the full load capacity of the generator, would that qualify for the 445.13 Exception that allows me to size conductors at 100% of the generator rating?

Seems like "yes," but....
Click to expand...

I could only think there's something in front of the generator that's smarter...

Frankly I can't defer to a dial up breaker on a Gennie, Go look at 450.4, and it states for 125%.

OK, per the Article you should be 115% - otherwise? OK Tag I'm It!

Besides this breaks our chain of thought of a Gen/Motor less than 125%. ;)
 
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big john

Senior Member
Location
Portland, ME
cadpoint said:
I could only think there's something in front of the generator that's smarter...

Frankly I can't defer to a dial up breaker on a Gennie, Go look at 450.4, and it states for 125%.
Click to expand...
So, are you saying it's technically permissable, but maybe just not a good idea? I don't quite follow....

-John
 
ceb58

ceb58

Senior Member
Location
Raeford, NC
I would say that you must size per 445.13. Which would be 115% of the name plate since you stated that the gen set doesn't have it's own OCP. The only thing I could think of that would allow you to follow the exception would be if the gen. had a over amp shut down built into it.
 
cadpoint

cadpoint

Senior Member
Location
Durham, NC
yeah what ceb said.... if you read the article, it says what it says, what You can do, I never gave it much thought till I read the article, seems I didn't say 115% where is says to use 115%, follow the Code... take it where it leads you... wait I did say 115... I'm going to stop bumming the keyboard
 
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