Embedded ground terminals are widely used in areas such as electrified high-speed railways, urban rail transit, power substations, petrochemical industries, and data centers. They are generally cast in copper or stainless steel and directly灌铸 into cable trays or other concrete products. According to IEC 62305-3 specifications: copper casting requires material purity of 98% or higher, while stainless steel casting requires materials with Cr≥17%, Ni≥8%, Mo≥2%, and C≤0.06%. Ground terminals for the beams, piers, and pier caps on bridges without cables for electrical railway systems are equipped with a single hole (M16). For roadbeds and pier caps on bridges with cable requirements, double holes (M16) are typically used, with the option for multiple holes (M16) in special cases for use as extended busbars.
Technical Requirements
1. Heat-welding is employed between copper terminals and galvanized round steel bars. The copper terminals are manufactured using hot forging technology, in accordance with IEC 62305-3 standards: the material purity should reach above 98% when copper casting is used. The direct current resistance at the welding point is less than 30μΩ, the overall resistance of a single embedded grounding terminal does not exceed 200μΩ, the area through which the terminal is焊接 with the lower material is not less than 800mm², and the current carrying capacity is not less than 600A.
2. The grounding terminal top features an M16 bolt hole. The M16 anti-theft bolt hole threads comply with the general threads required by GB3934. Additionally, the M16 bolt holes must be fitted with a plug and a plastic protective cap not exceeding 1mm in height to prevent concrete grout from entering during installation. The hole depth is 25mm, the galvanized round steel diameter is not less than Ø16, and the length is not less than 120mm. The specific length of the round steel is determined according to actual conditions.
3. The grounding terminal features anti-torque measures, such as side wings, to prevent the embedded grounding terminal from rotating synchronously and damaging the concrete or loosening the lower welds when the bolt is tightened.
Each embedded grounding terminal includes an M16 stainless steel anti-theft bolt, a stainless steel flat washer, and a spring washer.
