Which term indicates the requirement that a disconnecting means be lockable in place?

• A. Arc-flash hazard
• B. Locking disconnecting means
• C. Enclosure-type number mark
• D. Accidental contact prevention

Answer: (B)

Locking the disconnecting means is about ensuring energy isolation during service work. A disconnect device (such as a switch or circuit breaker) that can be locked in the open position provides a physical means to prevent re-energizing the circuit, typically using a padlock or similar device. This capability directly supports lockout/tagout practices and safety standards by guaranteeing the equipment stays de-energized while workers perform maintenance or inspections.

That’s why this term is the best answer: it precisely describes the requirement for a disconnecting means to be lockable to maintain a safe, de-energized state.

The other terms don’t fit because they describe different concepts: arc-flash hazard refers to the risk of arc-flash energy, not a feature of the disconnect; enclosure-type number mark concerns identification or rating marks on enclosures; accidental contact prevention relates to guarding to stop contact with live parts, not the locking capability of a disconnecting device.