The method of using bridge grounding wire mainly includes ensuring reliable connection between bridge bodies, protective connection between metal bridge and protective conductor, and laying of grounding trunk line.
First of all, the connection between bridge bodies is the key, which is usually achieved through so-called jumper connection. For galvanized bridge, there is no need to jumper the protective connection conductor between the bodies, but there should be at least 2 connection points at each end, which can be fastened with anti-loosening nuts or washers and bolts. For non-galvanized bridges, such as cable bridges sprayed with fire retardant paint or plastic sprayed, jumper protection should be performed. The grounding hole is not sprayed or a small area of paint is broken to ensure the reliability of the conductor contact surface, or a grounding claw pad (puncture washer) is used to destroy the insulation layer during the tightening process to effectively connect with the metal bridge.
Secondly, there are two main ways to lay the grounding trunk line: one is to lay 25×4 galvanized flat steel as the grounding trunk line for the entire length, and paint it with yellow-green paint; the other is to lay galvanized round steel of not less than Φ8 for the grounding trunk line for the entire length. These methods ensure the effectiveness and reliability of the grounding trunk line.
Finally, it should be noted that the treatment of the bridge grounding trunk line should meet the following points: At the beginning and end (or in the middle, etc.) of the bridge, connect the bridge to the grounding wire with a wire to ensure that there are no less than 2 grounding points along the entire length of the bridge. These grounding points can be ground wires without cable laying, or grounding terminals reserved in the power distribution room and power inlet. The bridge itself meets the grounding requirements, but it cannot be used as a grounding wire for other equipment. If there is equipment that needs to be grounded, it is necessary to lay a ground wire to the equipment so that the equipment can be connected to the ground wire. This ground wire can be one core of a five-core cable, or a dedicated grounding flat steel laid along the bridge.