AFAIK all inverters (except off-grid models) will refuse to work without mains power. it's also technical requirement, you have to synchronize to existing sine

AFAIK all inverters (except off-grid models) will refuse to work without mains power. it's also technical requirement, you have to synchronize to existing sine wave. the main reason such device is bad idea is that you might have power at exposed pins. In this case inverter will not produce any power until you already plugged into socket.