1. The metal frames and base steel of cabinets, screens, tables, boxes, and panels must be reliably grounded (PE) or connected to neutral (PEN); for operable doors equipped with electrical appliances, the grounding terminals of the door and the frame should be connected with bare braided copper wire and clearly marked.
2. Low-voltage switchgear, control cabinets (panels, consoles), and power and lighting distribution boxes (panels) shall have reliable electric shock protection. The protective conductor inside the cabinet (panel, console, box, panel) shall have exposed terminals for connecting to the external protective conductor. When there are no design requirements, the minimum cross-sectional area Sp of the protective conductor inside the cabinet (panel, console, box, panel) shall not be less than the specifications in Table 2.
3. Handcarts and withdrawable switchgear should slide smoothly without jamming or collision. The center lines of the moving and stationary contacts should be aligned, and the contacts should be in close contact. When engaging, the grounding contact should engage before the main contacts; when disengaging, the grounding contact should disengage after the main contacts.
4. High-voltage switchgear must pass the acceptance test according to the relevant specifications and should meet the following requirements:
① Individual relay protection components, logic elements, transmitters, and control computers passed the individual verification, the overall test operation was correct, and the setting parameters met the design requirements;
② New high-voltage electrical equipment and relay protection devices that have been approved through legal procedures and put into use in the market shall be handed over and tested in accordance with the requirements of the product technical documents.
5. The handover test of low-voltage switchgear must comply with the relevant specifications.
6. The insulation resistance values between lines and between lines and ground for wiring in cabinets, screens, platforms, boxes, and panels must be greater than 0.5MΩ for feeder lines and greater than 1MΩ for secondary circuits.
7. For the AC power frequency withstand voltage test of the secondary circuits between cabinets, screens, tables, boxes, and panels, when the insulation resistance value is greater than 10MΩ, use a 2500V megohmmeter to test for 1 minute, and there should be no flashover or breakdown phenomenon; when the insulation resistance value is between 1 and 10MΩ, perform a 1000V AC power frequency withstand voltage test for 1 minute, and there should be no flashover or breakdown phenomenon.
8. For DC power supply testing, electronic components inside the power supply should be disconnected from the circuit. The insulation resistance between main circuit lines and between lines and ground should be greater than 0.5MΩ. The charging and discharging of the battery pack attached to the DC power supply should meet the requirements of the product technical documents. The control adjustment and output characteristic test of the rectifier should meet the requirements of the product technical documents.
9. The installation of lighting distribution boxes (panels) shall comply with the following regulations:
① The wiring inside the box (panel) is neat and there are no twisted joints. The wires are tightly connected without damaging the core wires or breaking strands. The cross-sectional area of the wires pressed on both sides of the screw under the washer is the same, and no more than two wires are connected on the same terminal. Anti-loosening washers and other parts are complete;
② The switches inside the box (panel) operate flexibly and reliably, and the circuit is equipped with leakage protection. The operating current of the leakage protection device is not greater than 30mA and the operating time is not greater than 0.1s.
③ Inside the lighting box (panel), there are separate busbars for the neutral wire (N) and the protective earth wire (PE), and the neutral wire and the protective earth wire are distributed through the busbars.
