I recently got a couple of estimates for getting solar panels installed on our roof. (I am in Southern California.)

The first installer recommended that we get 8kW of solar, and he said it would be no problem to install.

The second installer said that the maximum amount of solar we could get is 4kW. He said that if we wanted more than 4kW of solar, this would require upgrading the wires from our house to the electric company (from 100 Amp to 200 Amp) and that doing so would be expensive and would require digging up the street to lay the new wires.

Any idea what the second installer is talking about? I don't understand why that would be needed, because if electricity is flowing from the power company to us, the amperage shouldn't be any more than it is currently. And if electricity is flowing from us to the power company, the amperage shouldn't be more than 33.3 Amps. (8kW at 240V.)