What must a branch-circuit switch or circuit breaker be capable of for a permanently connected appliance over 300 VA or 1/8 HP?

A branch-circuit switch or circuit breaker for a permanently connected appliance over 300 VA or 1/8 HP must be capable of being lockable. This requirement is crucial for safety reasons, as it allows the circuit to be properly isolated and secured during maintenance or repair work. Lockability prevents unauthorized or accidental operation of the switch, ensuring that employees or technicians can work safely on or near the appliance without the risk of unintentional energizing.

In the context of other options, while accessibility is important for operational convenience and safety, it does not specifically address the need for control over the operational state of the circuit during maintenance. Weatherproofing may be a requirement for certain installations, but it does not apply universally to all permanent appliances. Portability is not a relevant factor for permanently connected appliances, as they are designed to be fixed in place and not to be moved frequently. Thus, the focus on lockability stands out as an essential requirement in this scenario.