The safety of rural lighting electrical ready boards, as the end link of low-voltage distribution systems, directly affects the electrical safety of residents. In response to the high risk of lightning strikes, aging power lines, and large fluctuations in electricity load in rural areas, it is necessary to construct a protection system from three aspects: lightning protection, short circuit prevention, and overload prevention.

1、 Lightning protection: graded interception, multi-stage leakage

External lightning protection

Install independent lightning rods above the electrical ready board or use building lightning protection belts to ensure that lightning current is introduced into the grounding device through the down conductor, avoiding direct strikes on the electrical ready board. The grounding resistance should be ≤ 4 Ω, regularly tested and recorded.

Internal lightning protection

Install surge protectors (SPDs) at the incoming end of the electrical ready board, using a combination of "voltage limiting type+switch type" to discharge lightning current in stages. The first stage SPD (10/350 μ s waveform) is installed in front of the main switch, and the second stage SPD (8/20 μ s waveform) is installed in front of the branch circuit to ensure that the residual voltage is below the equipment's withstand voltage level.

2、 Anti short circuit design: quick cut-off, isolating faults

Circuit breaker selection

The main switch adopts a miniature circuit breaker (MCB) with short-circuit instantaneous tripping function, and the tripping current setting value is 5-10 times the rated current of the line; The branch circuit adopts residual current operated circuit breakers (RCD) with leakage protection function, with an operating current of ≤ 30mA and an operating time of ≤ 0.1s.

Line isolation

Each circuit inside the electrical ready board is separated by independent partitions to prevent arc propagation during short circuits; The wiring terminals are wrapped with insulation sheaths to prevent accidental contact or foreign objects from entering and causing phase to phase short circuits.

3、 Overload prevention management

Load calculation and wire selection

Based on the load characteristics of rural lighting and household appliances, select a wire cross-sectional area that is 1.2 times the long-term operating current of the line to avoid long-term overload operation. For example, when the total load is ≤ 10kW, the main line uses 6mm ² copper core wire.

4、 Maintenance and Training

Regular inspections

Check the grounding of the electrical ready board casing, SPD status indicator lights, circuit breaker opening and closing positions every quarter, and clean the dust and debris inside the box.

User safety education

Through village committee bulletin boards, power supply training, and other methods, popularize safe electricity usage knowledge such as "no unauthorized connections" and "high-power electrical dedicated circuits", and reduce risks from the source.

Through the above measures, the safety and reliability of rural lighting electrical ready boards can be significantly improved, and the incidence of electrical fires and electric shock accidents can be reduced.