The utility model provides a secondary short circuit device used in maintenance. An insulating shell is sleeved outside the air switch with the air switch handle; an air switch nesting screw is arranged at the lower part of the air switch; A mechanical baffle plate is arranged at the middle part of the insulating shell opposite to the air switch handle; the insulating shell is connected with the ground wire and the air switch nesting screw through fixing screws; The other end of the grounding wire is connected with a grounding wire handle. The five-prevention locking device is easy to operate,stable in connection and capable of achieving the five-prevention locking function, improves safety and saves labor cost, and a mechanical structure is locked. The device is suitable for being used as a secondary short circuit device during maintenance.