Rates are based on the amount of power consumed, not the size (capacity) of the service. Very large consumers get a lower cost per kwh, but pay a higher customer charge and also pay a demand charge based on the largest 15 minute amperage demand. If he increases hie service size to 400 amps, the power company will also charge him to upgrade their facilities to be able to provide that amount of service. Upgrading the transformer will cost him close to $3K (in addition to what he'll pay his electrical contractor to do the service upgrade on his equipment).
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