【Daily Topic】【Electrical Edition 20160428】
Thread Content
Participation reward: 2 Wealth. Reward for correct answer: 9 Wealth. Working on devices whose power supply is disconnected only via ( ) is prohibited ； It is necessary to create a gap ( ), so that there is at least one distinct ( ) in each aspect.
Working on equipment whose power supply has been disconnected only by a circuit breaker is prohibited； The circuit breaker (drawer compartment) must be pulled apart to ensure that there is at least one clear air insulation gap in all areas. Although high-voltage circuit breakers have strong breaking capacity, their opening stroke is very limited. The moving and stationary contacts of the circuit breaker are located within an organic arc extinguishing chamber; whether it is switched on or off is indicated only by the opening/closing indicator, which is not easily visible from the outside. More importantly, the power supply for operating the circuit breaker remains connected when it is in the off state; if there are problems with its control circuit or if there is cross-wiring, accidental contact, or improper operation, it can cause the circuit breaker’s operating mechanism to activate and close the circuit automatically, thereby energizing the equipment. Furthermore, when the opening mechanism of the circuit breaker operates to open it, if its operating mechanism fails and the circuit breaker does not actually open, the position indicator may still be moved to the open position by that mechanism, resulting in an apparent open state of the circuit breaker and creating a misleading illusion. Therefore, the Safety Regulations clearly state that it is prohibited to work on equipment whose power supply has been disconnected only by a circuit breaker. During maintenance outages, it is necessary to take the circuit breaker out of service, disconnect the load-side isolator and the busbar-side isolator, thereby creating a clear and visible air insulation gap to meet the requirements for work safety.
Circuit breaker, isolating switch, disconnection point
Circuit breaker, isolating switch, disconnection point
Circuit breaker, isolating switch, disconnection point
Circuit breaker switch, disconnecting switch, disconnection point
Circuit breaker, isolating switch, disconnection point
Circuit breaker, isolating switch, disconnection point
Working on equipment whose power supply has been disconnected only by a circuit breaker is prohibited； The disconnector must be opened to ensure that there is at least one clear break point in each section.
The circuit breaker has a distinct disconnection point and cannot reset automatically
Circuit breaker (switch), isolating switch (disconnector), breaking point