If RCCB (residual current circuit breaker) is selected for the lighting electrical Ready Board Box, its parameter settings must strictly follow the International Electrotechnical Commission standard IEC008-1 "Installation and Operation of Residual Current Operated Protective Devices" and low-voltage distribution design specifications.
1. Leakage action current:
For lighting electrical ready boards, which are usually terminal distribution lines, the rated residual operating current of their leakage protectors should be set to 30 mA.
This is a standard value that balances the safety of preventing electric shock and avoiding misoperation. 30 mA is defined as the "safety threshold" because the risk of ventricular fibrillation in the human body is controlled at an extremely low level when passing through this current. If the lighting circuit involves damp places (such as bathrooms, outdoor lighting, water pump rooms) or handheld/mobile devices, 30 mA must be selected. If used for overall protection or mainline protection (to prevent electrical fires), it can be set to 100 mA to 300 mA, but 30 mA should be preferred for the final lighting electrical ready board.
2. Action time:
For the action time (maximum interruption time), it is set to not exceed 0.1 seconds (i.e. 100 milliseconds).
Specifically, for residual current devices with a rated current ≤ 30 mA, it belongs to the auxiliary protection of direct contact protection, and the maximum breaking time requirement is:
Under I Δ n: ≤ 0.1 s
Under 5 times I Δ n: ≤ 0.04 s
Summary and Precautions:
Selection: It is recommended to use electromagnetic or electronic leakage protection circuit breakers (usually integrated with miniature circuit breakers, i.e. RCBO) with a rated residual operating current of 30 mA and a maximum breaking time of ≤ 0.1 s for lighting electrical ready boards.
Anti misoperation: Due to the possibility of electronic ballasts or LED driver power supply in the lighting circuit, there may be normal leakage current. To prevent frequent tripping of the main switch, the operating current of the leakage protector at the main incoming line of the electrical ready board can be appropriately amplified to 100 mA~300 mA (only for fire protection), but the end lighting circuit must strictly follow the standard of 30 mA/0.1 s.
In practical engineering, it is necessary to ensure that the operating current of the protector matches the normal ground leakage current of the circuit (usually requiring no more than 50% of the normal leakage current), in order to avoid unnecessary tripping and affecting lighting safety.