the inverter has past the CE certificate.its input is separated from the output to protect the working machine.it can work for 24 hours all the day but not 7 hours for most of the ordinary inverter.so please feel free to contact eastsecretary(at)163(dot)com DC-AC Inverter is electrical apparatus turning direct current into alternating current 220V, 50HZ. It adapts popular international quasi-sine converting circuit, effective conversion performance, fully automatic protection, reliable and safe operation, widely used in wind energy, solar energy power generation conversion and field work, travel, lighting, computer, TV and electrical tools.