Tesla Motors Club
Duke Energy Florida's interconnect process for systems with greater than 10kW includes a verification that the PV system does not produce more than 90% of the rating for the service cable and transformer. If it does, we pay for service cable and transformer upgrades as applicable.
We have a 150 amp main service disconnect outside next to the meter with other breakers for improvements made by the former owners. The indoor panel is full and has cheaters, that's likely why the breakers for the improvements are in the outdoor panel, it had room.
So if I math right, 150 amps, 120 volts, that's 18kW. I've ordered XL. It's not the 16.32 vs. 16.2 (90% of 18) that concerns me, it's that I want to add panels. I only have bills since we moved in April, 2300kWh used in May and again in June, and the current XL layout first year production estimate is 24MWh.
I have the roof to add 8 panels for a total of 19.04kWh. I might need to pay for at least a service cable upgrade and possibly a transformer upgrade, but I won't know for sure until permits are submitted and the Duke engineer reviews the interconnect request. Ideally I don't want to wait that long to find out.
I expect that the main breaker is 150 amps because that is what is specified to protect the service cable based on the cable's wire gauge. In 2003 construction, I would not expect that my service cable is oversized for my main breaker.
Are my math and assumptions right? Anything I'm missing? Main panel upgrade? Sounds like I need to hire an electrician to look at the service cable before I expand the system and run into fees from Duke. Should I be able to get Duke to come out and advise me before I proceed with a design?
We have a 150 amp main service disconnect outside next to the meter with other breakers for improvements made by the former owners. The indoor panel is full and has cheaters, that's likely why the breakers for the improvements are in the outdoor panel, it had room.
So if I math right, 150 amps, 120 volts, that's 18kW. I've ordered XL. It's not the 16.32 vs. 16.2 (90% of 18) that concerns me, it's that I want to add panels. I only have bills since we moved in April, 2300kWh used in May and again in June, and the current XL layout first year production estimate is 24MWh.
I have the roof to add 8 panels for a total of 19.04kWh. I might need to pay for at least a service cable upgrade and possibly a transformer upgrade, but I won't know for sure until permits are submitted and the Duke engineer reviews the interconnect request. Ideally I don't want to wait that long to find out.
I expect that the main breaker is 150 amps because that is what is specified to protect the service cable based on the cable's wire gauge. In 2003 construction, I would not expect that my service cable is oversized for my main breaker.
Are my math and assumptions right? Anything I'm missing? Main panel upgrade? Sounds like I need to hire an electrician to look at the service cable before I expand the system and run into fees from Duke. Should I be able to get Duke to come out and advise me before I proceed with a design?