USCG Exam PracticeMotor controllers and remote control
Under 46 CFR §111.70-7, when a control, interlock, or indicator circuit cannot be energized from the load side of the motor disconnect device and its voltage exceeds 24 volts, one permissible alternative is to use a separate independent disconnect device for the control circuit. What additional requirement applies to that arrangement?
- ✓ The two independent disconnect devices must be adjacent to each other, and a fixed warning sign must be on the exterior door of the main disconnect deviceCorrect
- B. The control circuit disconnect must be interlocked so it opens automatically whenever the main motor disconnect is opened
- C. The control circuit disconnect must be located in a separate compartment from the motor disconnect to prevent simultaneous access
- D. A nameplate warning that opening the door will trip a vital auxiliary off-line must be affixed to the controller door
Why A is correct
46 CFR §111.70-7(d)(1) requires that when a separate independent disconnect is used for the control circuit, the two devices must be adjacent to each other and a fixed sign warning the operator to open both devices must appear on the exterior of the main disconnect door. The nameplate warning in option D applies to the door-actuated disconnect arrangement under §111.70-7(d)(2), not the independent device arrangement.
Cited:46 CFR §111.70-7