Dwelling Unit Feeder Size

[Urko]

Good day,
Happy Independence Day!
I am working on renovation project with multiple dwelling units -120/240V, 1ph service.
Per NEC 220, I have calculated loads for:
1BR (single bedroom) -72 Amps,
2BR (two) -74 Amps,
3BR (three)-79 Amps.
There is existing feeder and 100 Amps circuit breaker/meter bank for each dwelling unit, with #2 Al, THHW in EMT.
The owner would like to reuse existing electrical feeder and wires from the service to the electrical panel located in the dwelling unit. The electrical panel and service will be new ones.
Per Table 310.15 (B)(6) #2 Al is good for 100 Amps. Per 110.14 we shall use 60 degree Al THHW ---- >> 75 Amps.
I am not still completed clear for the items below:
1. Shall I comply with 110.14 or only with Table 310.15 (B)(6)?
2. Are there any other code wire considerations that will require to upsize the feeder wires (voltage drop is not an issue)?

 

[Dennis Alwon]

IMO, 310.15(B)(6) can be used. Also the 60 C rating would only be in effect if the terminals or wire was rated 60C. THHW is good for 75C so if the terminals in the panel are rated 75C then you could use 75C.

Assuming that the #2 going to the apts carry the entire load of the apt. then I see no issue as T. 310.15(B)(6) clearly states THHW in the heading.

 

[Urko]

Thank you!

Thank you!

IMO, 310.15(B)(6) can be used. Also the 60 C rating would only be in effect if the terminals or wire was rated 60C. THHW is good for 75C so if the terminals in the panel are rated 75C then you could use 75C.

Assuming that the #2 going to the apts carry the entire load of the apt. then I see no issue as T. 310.15(B)(6) clearly states THHW in the heading.

Thank you for your clarification.