As the core of circuit terminal control, the lighting electrical ready board is equipped with miniature circuit breakers (MCBs) and residual current devices (RCDs), which are two key components to ensure electrical safety. They complement each other's functions and work together to build a circuit safety defense line.

The core function of MCB is overload and short circuit protection, with circuit on/off control function, equivalent to an upgraded version of traditional fuses, which can be reused without replacement. When the current in the circuit exceeds the rated value (overload) due to excessive electrical appliances, the bimetallic strip inside the MCB is deformed by heat, which drives the trip mechanism to disconnect the circuit, avoiding overheating of the wires and causing a fire; If a short circuit occurs in the circuit (with a sudden increase in current), the electromagnetic release will generate strong suction force, triggering a trip instantly, quickly cutting off the power supply, and protecting electrical equipment from damage caused by high current. In addition, MCB can be manually opened and closed, facilitating daily circuit maintenance and repair, and is the basic protective component for lighting circuits and socket circuits.

RCD focuses on * * leakage protection * *, providing protection against human electric shock and line leakage risks, and compensating for the shortcomings of MCB in leakage protection. Its working principle is based on the principle of current balance. During normal operation, the current of the live and neutral wires is equal in magnitude and opposite in direction, and the magnetic fields cancel each other out. The RCD remains closed; When the human body is electrocuted or the insulation of the circuit is damaged, some of the current will flow through the human body or the leakage point to the ground, causing an imbalance between the live and neutral line currents, with a difference exceeding the set threshold (usually 30mA). The RCD will quickly trip within 0.1 seconds, cut off the power supply, avoid human electric shock injuries, and prevent fire hazards caused by leakage.

In practical applications, the two are often used in combination: MCB is responsible for overload and short circuit protection of the line foundation, while RCD is combined with leakage protection, especially suitable for circuits in humid environments (such as bathrooms, kitchens) and densely populated areas. Reasonable configuration of MCB and RCD can comprehensively cover electrical safety risks and provide reliable protection for lighting and electrical equipment in homes and commercial places.