At what voltage level does trained or authorized personnel supervision become generally required for live work?

• A. For voltages typically above 15 volts, training is not generally required.
• B. For voltages typically above 600 volts, training is mandatory.
• C. Supervision is never required for any voltage.
• D. For voltages typically above 50 volts (AC or DC), work closer to exposed live parts requires training and authorization.

Answer: (D)

Working near exposed live parts is dangerous, so safety standards require that people doing that kind of work have proper training and authorization. The general guideline used in many programs is that when voltages are above about 50 volts (AC or DC), supervision by trained or authorized personnel is needed. This ensures the worker knows how to de-energize equipment when possible, follows proper energy-control procedures, uses appropriate PPE, and follows safe work practices to reduce the risk of shock or arc flash. The lower threshold (15 volts) would understate the risk, while a threshold of 600 volts is not the typical general rule—higher voltages do demand stricter controls, but the standard practice for initiating required supervision is around 50 volts. Saying supervision is never required is inconsistent with established safety protocols.