Question on size of service conductors for multifamily bldg.

[aksparky]

I have a 5 unit bldg I need to hang a service on, the 5 unit service pack I am getting carries a 400 amp rating.
When I did the load calculation for all 5 units it computes to approx. 215 amps (all gas appliances and laundry is house panel).
Questions is, doesnt the load calculation dictate the size of the wire pulled up the mast for the service point not the rating of the gear?
Thanks in advance for any input

 

[raider1]

I have a 5 unit bldg I need to hang a service on, the 5 unit service pack I am getting carries a 400 amp rating.
When I did the load calculation for all 5 units it computes to approx. 215 amps (all gas appliances and laundry is house panel).
Questions is, doesnt the load calculation dictate the size of the wire pulled up the mast for the service point not the rating of the gear?
Thanks in advance for any input

The service entrance conductors are sized in accordance with 230.42(A).

If you load calculation is 215 amps and that includes 100% of the non continuous and 125% of the continuous load then that is what you can base your conductor size on.

Chris

 

[Buck Parrish]

Both,
Just have the poco install the service undrground...

 

[suemarkp]

But don't forget 230.90. If that 5 meter pack has a 400A main, then the conductors have to be rated for 400A (or at least 351 amps or more if you round up to the 400A standard size).

 

[aksparky]

thanks for the replys,
I had a discussion with another electrician who is more experienced than myself and he was adament that they had to be sized for the gear which made me second guess myself.

Thanks again

 

[aksparky]

But don't forget 230.90. If that 5 meter pack has a 400A main, then the conductors have to be rated for 400A (or at least 351 amps or more if you round up to the 400A standard size).

No main, there will be 5- 60 amp breakers, 1 for each unit.

 

[suemarkp]

With 5 separate grouped disconnects, you're fine. Just provide conductors that meet or exceed the calculated load.

 

[iwire]

To follow up with what the others have been saying

230.90(A)

Exception No. 3: Two to six circuit breakers or sets of fuses
shall be permitted as the overcurrent device to provide the
overload protection. The sum of the ratings of the circuit
breakers or fuses shall be permitted to exceed the ampacity
of the service conductors, provided the calculated load
does not exceed the ampacity of the service conductors.

 

[M4gery]

No main, there will be 5- 60 amp breakers, 1 for each unit.

What about the house panel?