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1

Originally Posted By: jpeck
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Joe T., Bob B., Rob, and anyone,


House today had 600 amp service with Cutler-Hammer Commercial breakers, labeled as being only 40 degrees C.

That means that all components in that enclosure must be used at their 40 degree C rating, right?

The NEC 310-15 charts only go down to 60 degree C. What is the reduction factor to 40 degree C? Is there any?

I know that is the insulation rating, but the limitation will be the termination rating (40 degree C). Any reduction in ampacity for the conductors?

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Jerry Peck
South Florida

2

Originally Posted By: Bob Badger
This post was automatically imported from our archived forum.


Jerry it has to due with ambient temp the breakers are operating in, not the termination temp. icon_smile.gif


From the UL White Book.
Quote:
TEMPERATURE

Circuit breakers, the performance of which may be affected by a 40 C ambient temperature within the enclosure and have been evaluated for this application, are marked ??40 C.


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Bob (AKA iwire)
ECN Discussion Forums
Mike Holt Code Forum
3

Originally Posted By: jpeck
This post was automatically imported from our archived forum.


I knew my head was screwed on wrong today. I could not come up with that for the life of me.

–
Jerry Peck


South Florida

4

Originally Posted By: Bob Badger
This post was automatically imported from our archived forum.


Jerry, If I was only paid by the amount of times I have suffered from the same problem I could stop going to work. icon_redface.gif


Bob

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Bob (AKA iwire)
ECN Discussion Forums
Mike Holt Code Forum

5

Originally Posted By: Mike Parks
This post was automatically imported from our archived forum.


Jerry


What is the AIR rating?

Would you call out the older 5000 AMP rated breakers?

Do you verify with the utility in regards to the service AMP rating?

I grabbed the first breaker I could find.

It is a Siemens AFCI breaker: It states that it is 40o's. 'Ues 60/75C' Cu/Al wire.

It is HACR not HAVCR.

Mike P.

6

Originally Posted By: jpeck
This post was automatically imported from our archived forum.


Mike,


This is brand new stuff (okay, one year inspection, basically, that is brand new stuff).

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Jerry Peck
South Florida