Live parts of motors must be guarded if they operate at or over how many volts?

• A. 150 volts
• B. 50 volts
• C. 100 volts
• D. 75 volts

Answer: (B)

Guarding exposed energized parts is required to prevent accidental contact and shock. The safety rule sets the threshold at 50 volts or more; when motors or other equipment have live parts at or above 50 V, they must be protected by barriers, enclosures, covers, or other physical guards. This protects workers from contacting terminals, conductors, or other energized components that could deliver a hazardous shock or arc.

In practice, you’ll see guards on motor terminals, wiring, brushes, and similar components to keep them out of reach. The other voltage options are not the standard threshold used for this requirement, since 50 V is the point at which guarding becomes mandatory to reduce shock risk.