Glossary · Electrical engineering and control panels
Circuit breaker
Also known as: Miniature circuit breaker (MCB)
German: Leitungsschutzschalter
In electrical installation, a circuit breaker is a mechanical switching device that carries and interrupts currents and trips automatically on overload or short circuit; the German term Leitungsschutzschalter specifically denotes the miniature circuit breaker protecting cables and circuits.
- Control panels
In one sentence
A circuit breaker trips automatically on overload or short circuit and can be reset; the miniature version protects cables and circuits.
Example
Each 230 V socket circuit in the control cabinet is protected by a miniature circuit breaker with a C characteristic.
How it applies
- Engineering: Select rated current, tripping characteristic (B, C, D) and breaking capacity based on cable cross-section, load type and prospective short-circuit current. Miniature circuit breakers for household-type use follow IEC 60898-1; industrial circuit breakers follow IEC 60947-2.
- Operation: A tripped breaker indicates a fault; resetting it repeatedly without finding the cause is dangerous.
- Documentation: The circuit diagram lists each breaker with rating and characteristic. Maintenance manuals should state who may reset breakers, and warn that switching off a breaker is not a substitute for Energy isolation with Lockout/tagout (LOTO) unless it is designed and approved for that purpose.
Circuit breaker vs. fuse
A circuit breaker can be reset after tripping; a Fuse must be replaced. Fuses often have higher breaking capacity and faster current limitation; breakers are more convenient and can serve as switches.