In a three-phase electrical system, an RCBO combines the functions of an RCD (Residual Current Device) and an MCB (Miniature Circuit Breaker) into a single unit. It provides protection against earth leakage (residual current) and overcurrents (such as short circuits and overloads) for individual circuits.

RCBOs are commonly used in consumer units (distribution boards) in three-phase electrical installations to provide enhanced protection for circuits supplying sockets, lighting, machinery, and other electrical loads.

RCBOs offer the advantage of combined protection in a compact unit, which simplifies installation and saves space in the consumer unit. Each RCBO protects a specific circuit against both earth faults (RCD function) and overcurrents (MCB function), reducing complexity and enhancing fault-finding capabilities.

RCBOs are installed similarly to MCBs and RCDs in three-phase consumer units. Proper installation involves securely wiring the RCBO into the circuit and ensuring it is correctly labeled for identification and maintenance purposes.

RCBOs can be integrated into smart home systems for enhanced monitoring and control capabilities. Ensure compatibility with smart home controllers and systems when selecting RCBOs for integration.