YRO Solar electric components were used for 20KW Solar Roof Project in Ho Chi Minh, Vietnam. The AC and DC combined IP65 waterproof distribution boxes are used for this project. Our TUV and CE certificate DC circuit breaker and DC SPD were used to project the solar system from the short circuit and lightning strike. The YRQ4PC-125 Series automatic transfer switch can install on the din rail and the transfer time is less then 30ms which can make the electric uninterrupted.