Residential feeders

[RicardoC77]

When sizing residential service “feeder” on a multi-family dwelling unit, from the meter center to each unit interior panel; NEC 310.12 ( B ) applies.
“shall be permitted to have an ampacity not less than 83% of the feeder rating.”

Question is:
Does voltage drop is has to be considered and wire size adjusted per VD calculation?

I have some feeders that range between 220-380’ long.

 

[infinity]

There is no voltage drop compensation required in the NEC for these feeders. It's a design issue.

 

[RicardoC77]

There is no voltage drop compensation required in the NEC for these feeders. It's a design issue.

My project plans just indicate by a key note; “provide 125A aluminum service feeder to respective living unit panel.”

My assumption based on the 83% factor on 125A, aluminum feeder wire is 1/O. Just wanted to make sure since some of the unit panels are very long distance.
Is my assumption correct?

 

[infinity]

Are they paying for 125 amps or 83% of 125 amps?

 

[rc/retired]

My project plans just indicate by a key note; “provide 125A aluminum service feeder to respective living unit panel.”

I would send the plans back to the designer/engineer and have them provide the information.

Ron