noun
An electrical safety device that automatically interrupts current flow when a fault is detected. Common in technical and everyday contexts.
遮断器が落ちたので、ブレーカーを上げてください。
The circuit breaker tripped, so please reset the breaker.
この遮断器は過電流を検知すると自動的に回路を
This circuit breaker automatically cuts off the circuit when it detects overcurrent.
A disconnector (isolator) used to ensure a circuit is completely de-energized for maintenance, not designed to interrupt load current like a circuit breaker.
Compound of 遮断 (shadan, 'interruption, cutoff') + 器 (ki, 'device, instrument'). The term follows a common pattern for naming technical devices.