Feeder sizes for 6 units

[dcooper]

I am sizeing up a 400 Amp service.400 amp switch, 6 meter/discos w/ a house meter. Can someone explain to me the the words' Individual Dwelling UnitS' as used in 310-15 for my overhead. It seems to me the word 'Individual' cotradicts multi family dwelling.

 

[Volta]

I am sizeing up a 400 Amp service.400 amp switch, 6 meter/discos w/ a house meter. Can someone explain to me the the words' Individual Dwelling UnitS' as used in 310-15 for my overhead. It seems to me the word 'Individual' cotradicts multi family dwelling.

Yup, the 'main power feeder' to each 'individual dwelling unit' can make use of 310.15(B)(6), one by one, but not for any feeder or service that supplies more than one dwelling unit, nor for any feeder that supplies less than one entire dwelling unit's load.

You may be able to take advantage of 220.84, though.

 

[dcooper]

310.15(6)
For individual dwelling units of one family, two family, and multi family dwellings..................
So I can still use 310.15b(6) table, correct for the service lateral

 

[OTT2]

310.15(6)
For individual dwelling units of one family, two family, and multi family dwellings..................
So I can still use 310.15b(6) table, correct for the service lateral

Yes, you may use Table 310.15(B)(6) for service entrance conductors and service-lateral conductors

 

[Volta]

310.15(6)
For individual dwelling units of one family, two family, and multi family dwellings..................
So I can still use 310.15b(6) table, correct for the service lateral

No, not for a lateral to multiple residences.

It can only be used when the entire load - of only one dwelling - is carried on one set of conductors.

Otherwise use T310.16.

 

[OTT2]

No, not for a lateral to multiple residences.

It can only be used when the entire load - of only one dwelling - is carried on one set of conductors.

Otherwise use T310.16.

Thanks Volta, I see my error!!

 

[erickench]

If you had six dwelling units then each unit would have it's own feeder. Each feeder would be sized according to NEC 310.15(B)(6).

 

[dcooper]

i'm looking for the wires for the 400amp main switch........

 

[Volta]

i'm looking for the wires for the 400amp main switch........

600 kcm if you do not know the load, 500 kcm is ok if your calc shows not more than 380 amps and will not be exceeded in the future T310.16 (copper, of course) 110.5.

Or paralleled 3/0s for a full 400 amps.