According to Technical Specification for Temporary Electricity Safety in Construction Site (JGJ46-2005), the copper conductor is not less than 25mm2. When the PE line, the phase line and the working zero line (n) are made of the same material, the minimum cross section of the PE line conforms to the provisions in Table 5. 1.8.
The main consideration in selecting the diameter of grounding wire for equipment protection is the working current of the equipment. The selection of grounding wire diameter for communication equipment protection can refer to GB 4943-200 1 Safety of Information Technology Equipment. Generally speaking, the diameter of protective grounding wire of actual equipment should be greater than or equal to the cross-sectional area corresponding to the rated current in the table.