What is the purpose of grounding exposed metal parts of portable control devices?

What is the purpose of grounding exposed metal parts of portable control devices?

• A. To interrupt current flow during maintenance
• B. To prevent nuisance tripping of breakers
• C. To provide a low-resistance path to ground
• D. To increase the heating of components

Answer: (C)

Grounding exposed metal parts of portable control devices creates a low-resistance path for fault current to reach the earth. This keeps the metal surfaces at or near earth potential, so if a live conductor accidentally touches the metal, the fault current has a direct route back to the source. That sudden surge triggers the protective device (like a breaker or fuse) to interrupt power quickly, reducing the risk of electric shock or fire. It’s about safely handling faults, not about interrupting maintenance or preventing nuisance trips, and it doesn’t cause increased heating of components.

Grounding exposed metal parts of portable control devices creates a low-resistance path for fault current to reach the earth. This keeps the metal surfaces at or near earth potential, so if a live conductor accidentally touches the metal, the fault current has a direct route back to the source. That sudden surge triggers the protective device (like a breaker or fuse) to interrupt power quickly, reducing the risk of electric shock or fire. It’s about safely handling faults, not about interrupting maintenance or preventing nuisance trips, and it doesn’t cause increased heating of components.