What protection is provided for mobile equipment that uses trailing cables?

What protection is provided for mobile equipment that uses trailing cables?

• A. Frame grounding
• B. Ground fault interrupter at every outlet
• C. Insulation tape around the plug
• D. Floating power supply

Answer: (A)

When mobile equipment uses trailing cables, the key protection is a solid path to earth for fault current. Frame grounding provides that path by connecting the equipment frame to the grounding conductor in the trailing cable. If a live conductor touches the frame, the fault current travels directly to ground, causing the protective device (fuse or breaker) to trip quickly and disconnect power. This keeps the metal parts at earth potential and reduces the risk of electric shock to anyone who might touch the frame. Other options don’t provide the same reliable protection in this setup. A ground fault interrupter at every outlet helps with certain fault scenarios, but the fundamental safeguard for mobile equipment with trailing cables is that the frame is continuously earthed. Insulation tape around the plug is not a dependable protective measure, and a floating power supply removes the necessary earth reference, increasing shock risk.

When mobile equipment uses trailing cables, the key protection is a solid path to earth for fault current. Frame grounding provides that path by connecting the equipment frame to the grounding conductor in the trailing cable. If a live conductor touches the frame, the fault current travels directly to ground, causing the protective device (fuse or breaker) to trip quickly and disconnect power. This keeps the metal parts at earth potential and reduces the risk of electric shock to anyone who might touch the frame.

Other options don’t provide the same reliable protection in this setup. A ground fault interrupter at every outlet helps with certain fault scenarios, but the fundamental safeguard for mobile equipment with trailing cables is that the frame is continuously earthed. Insulation tape around the plug is not a dependable protective measure, and a floating power supply removes the necessary earth reference, increasing shock risk.