USCG Exam PracticeElectrical troubleshooting and maintenance
Under 46 CFR §111.95-3, a main line emergency disconnect switch is accessible to unauthorized persons. Which of the following correctly states the regulatory requirement for that switch?
- A. The switch must be locked in the closed-circuit position to ensure continuity of emergency power
- ✓ The switch must have a means to lock it in the open-circuit position with a padlock or equivalent, and must not lock in the closed-circuit positionCorrect
- C. The switch must be relocated to a space accessible only to licensed personnel, and no locking device is required once relocated
- D. The switch must be capable of locking in both the open and closed positions to allow operational flexibility
Why B is correct
46 CFR §111.95-3(b) requires that each main line emergency disconnect switch accessible to an unauthorized person have a means to lock the switch in the open-circuit position with a padlock or its equivalent, and explicitly states the switch must not lock in the closed-circuit position. Locking in the closed position would defeat the safety purpose of the disconnect.
Cited:46 CFR §111.95-3