Metal cable trays and their supports, as well as metal cable conduits introduced or led out, must be reliably grounded (PE) or grounded (PEN) and comply with the following regulations:
1. The total length of metal cable trays and supports should be connected to the grounding (PE) or neutral (PEN) main line at no less than 2 points;
2. The two ends of the connecting plate between non galvanized cable trays shall be connected by a copper core grounding wire, and the minimum allowable cross-sectional area of the grounding wire shall not be less than 4mm2;
3. The two ends of the connecting plate between galvanized cable trays shall not be connected to the grounding wire, but there shall be no less than 2 connection fixing bolts with anti loosening nuts or anti loosening washers at both ends of the connecting plate.
