An RCCB (Residual-Current Circuit Breaker) is a safety electrical device that protects against electric shock and fire by monitoring current leakage and rapidly interrupting the circuit. It works on the principle that in a healthy circuit, the current flowing in must equal the current flowing out. If it detects a difference, it assumes a fault is occurring and shuts off the power.

How it works

Current comparison: An RCCB continuously compares the electrical current going into a circuit with the current coming back out.
Leakage detection: If the live and neutral currents are unequal, the device assumes current is leaking, likely through a person or faulty appliance.
Rapid interruption: The RCCB immediately trips and breaks the circuit, shutting off the power to prevent serious harm or fire.
Sensitivity: RCCBs have a sensitivity rating, often measured in milliamperes (mA), that determines how small a leakage current will cause it to trip.

Applications and types

Protection: RCCBs protect against earth faults and leakage currents, which are especially important for preventing electric shock.
Location: They are typically installed in a building’s distribution or breaker box.
Types: They are available in different types (e.g., AC, A, B) to detect various types of currents, and some include a “Test” button to verify functionality.
Tripping levels: Sensitivity levels, such as 10mA or 30mA, are chosen for shock protection, while higher ratings like 100mA or 300mA are for fire and equipment protection.