A permanently connected appliance is rated over 300 volt-amperes. Under what condition is the branch-circuit switch or circuit breaker permitted to serve as the required disconnecting means for that appliance?
- AOnly when the appliance draws under 30 amperes and is supplied by a dedicated individual branch circuit
Ampere rating and circuit dedication are not the qualifying conditions. A 300 volt-ampere threshold determines which rule applies, but nothing in it keys on 30 amperes or on the circuit being individual.
- When the switch or breaker is within sight from the appliance, or is capable of being locked in the open position
- COnly when a qualified service technician is present during any energized work on the appliance
Personnel qualifications are governed by workplace safety practice, not by the Code section that establishes the appliance disconnecting means.
- DWhen the panelboard directory identifies the appliance, regardless of distance or locking capability
Directory identification is required for panelboard circuits generally, but knowing which breaker feeds the appliance does not prevent someone from closing it while a technician has hands in the equipment.
Why B is correct
The rule gives two acceptable ways to guarantee the servicer controls the energy source: either the device is visible from the appliance, or it can be locked open so nobody restores power while work is underway. Both conditions target the same hazard from different directions.
What this question is testing
This tests the two-part appliance disconnect rule and whether you can distinguish real disconnect control from circuit identification. The same in-sight-or-lockable structure recurs for motors, air conditioning equipment, and heating equipment.
On the job
Attic fans, ceiling heaters, water heaters, and disposals all raise this question during rough-in. Field practice is simple: if the panel is not visible from the equipment, either install a local switch at the appliance or specify a breaker with permanently installed lockout provisions. Note that the locking means must stay attached to the breaker or panel when the lock is off, which rules out the loose lockout devices some technicians carry in a pouch. A local switch is usually cheaper and never gets argued about at inspection.
Memory technique
See it or lock it, otherwise install a switch at the appliance.
Exam tip
In sight or lockable open is a pattern that repeats through the Code. Learn it once and apply it across articles.
Where to look it up
Article 422 Part III, the appliance disconnecting means sections, plus the general lockable-disconnect requirements in Article 110.