The utility model provides an earth connection is prevented the mistake and is torn the subassembly open, the subassembly includes a plurality of first parts and a second part, the constitution is connected by locking portion and reservation portion to every first part, and the partial other demountable installation of every locking is on the ground of earth connection subassembly wire hook and lock the earth connection, and the reservation portion of a plurality of first parts forms the structure of taking the arris or taking edges and corners after the concatenation, the second part comprises fixed part and the connection of dismantlement portion, the fixed part is for having the internal screw thread ring -shaped structure to screw the ground wire on the ground connection hook nail, be equipped with the through -hole in the middle of the dismantlement portion, shape after the concatenation of a plurality of reservation portions can be inserted through -hole and rather than the looks adaptation. In addition, still provide the ground wire device that connects who has this subassembly, dismantled the earth connection through first part in this subassembly and the cooperation of second part, made more convenient, the safety of disassembling operation of device.