705.12(D)(2)

[Tank11]

I have a new service at 200-amps with a 200-amp MCB. In order to install a larger PV system, I want to install a 175-amp MCB. The calculated loads in the building are less than 175-amps.

Question: Can I install the service feeder to be rated at 175-amps as well instead of the 200-amps? Or does the service need to remain at 200-amps because of the bussing in the main board?

It's not a lot of money but it could be if the service were much larger and it was a long run to the utility transformer.

 

[ggunn]

I have a new service at 200-amps with a 200-amp MCB. In order to install a larger PV system, I want to install a 175-amp MCB. The calculated loads in the building are less than 175-amps.

Question: Can I install the service feeder to be rated at 175-amps as well instead of the 200-amps? Or does the service need to remain at 200-amps because of the bussing in the main board?

It's not a lot of money but it could be if the service were much larger and it was a long run to the utility transformer.

I am pretty sure that the service conductors can be smaller if the breaker that is the main service disconnect has a lower rating.

 

[jaggedben]

The NEC would allow what you want to do. I've run into one municipal utility that requires the service conductors to be rated the same as the panelboard, though.

Another option (probably) would be to install a 'solar ready' panel with a 200A breaker and a 225A busbar. That might be more to the customer's liking if the original request was for a 200A service.