The one-line shows two possible sources to the maintenance point. What is required before work begins?
- Lock out every source and verify
- BOpen only the utility breaker
- CPress STOP and rely on the pilot light
- DBegin after the generator engine stops
Why A is correct
Multiple sources can backfeed the work zone even when one source or control is off. The electrically safe work process requires complete source identification, isolation, lockout or tagout, stored-energy control, and a properly performed absence-of-voltage test.