Are These Feeders Overfused ?

[ramsy]

50+ year old 125A meter center, with #10cu on 40A breakers

* Was the 83% factor ever allowed for 40A feeders, similar to NEC 310.12 for =>100A feeders ?

* Were #10cu feeders @ 75C allowed at their 35A rating, some time before T.310.16 foot Note: referenced 240.4(D) for small conductors ?

 

[LarryFine]

Not to mention derating for eight (or seven) CCCs in a single conduit.

 

[ramsy]

Not to mention derating for eight (or seven) CCCs in a single conduit.

Yes, now that you mention it, the ampacity is only good for 28 Amps, with 7-9 CCC's

1" raceway can handle fifteen #10cu THHN

With 120v to ground, the bonding busing may not be required

 

[LarryFine]

With 120v to ground, the bonding busing may not be required

I don't see one.

 

[don_resqcapt19]

Was the 83% factor ever allowed for 40A feeders, similar to NEC 310.12 for =>100A feeders ?

There have rules for reduced size dwelling unit feeder and service conductors in the code for a long time. In the past it was just a table without any reference to 83%.
The oldest code book I have is the 1975. In that edition, the rule was found as Note 3 to Tables 310-16 through 310-19. Like now, the rule started at 100 amps.
Do the feeders in the picture carry 100% of the dwelling unit load? c