Why not when grid connected? The problem arises when you are grid connected.
You draw 31 amps from the grid, you draw 6-7 per battery or solar installation behind the circuit breaker. The circuit never trips because the amount crossing the breaker is 31 amps, but the wires could be dealing with 37+. With battery and solar that could be 43+. Some idiot puts two or three of these in their house or puts them on an extension cord, wires are going to get warm.
You draw 31 amps from the grid, you draw 6-7 per battery or solar installation behind the circuit breaker. The circuit never trips because the amount crossing the breaker is 31 amps, but the wires could be dealing with 37+. With battery and solar that could be 43+. Some idiot puts two or three of these in their house or puts them on an extension cord, wires are going to get warm.