Circuit Breaking

• A. A metering process
• B. The function of safeguarding electrical equipment
• C. A task performed by equipment within substation cubicles to interrupt the flow of electricity during faults.
• D. An electrical device used to change voltage

Answer: (C)

Circuit breaking is the action of stopping current flow to clear faults and protect people and equipment. In a substation, protective relays detect abnormal or fault conditions and trigger a circuit breaker to open. When the breaker opens, the circuit is interrupted, quickly interrupting the fault current and preventing damage or escalation. This is different from metering, which just measures energy, and from devices that change voltage, whose purpose isn’t to interrupt current during faults. The phrase describes the task of equipment inside substation cubicles performing the interruption to keep the system safe.