The removable metal plate in the combiner box is not connected with the protective ground wire system, which is a common installation problem of the combiner box.

Consequence: the detachable metal plate in the combiner box is equipped with various electrical accessories and is not connected with the protective ground wire, which is easy to cause electric shock accidents.

Measures: the detachable metal plate in the combiner box shall have reliable grounding protection. Therefore, it is required that the metal plate shall be provided with non detachable special grounding screw, and the protective ground wire shall be effectively connected with it. The wire diameter of protective ground wire shall be configured according to the requirements of specifications and standards to ensure safe use.