Hangar deck certified power grounds should be tested to the current standard of less than how many ohms?

Hangar deck certified power grounds should be tested to the current standard of less than how many ohms?

• A. 15 ohms
• B. 20 ohms
• C. 25 ohms
• D. 30 ohms

Answer: (C)

Grounding systems must provide a low impedance path to earth so fault currents can return quickly and trip protective devices, keeping people safe and protecting equipment. For hangar deck certified power grounds, the current standard sets a maximum earth resistance of twenty-five ohms. Measurements should be below this value to meet the requirement; if the reading is higher, the grounding system needs improvement (more low-resistance paths, better connections, etc.). This twenty-five-ohm limit is chosen as a practical safety threshold.

Grounding systems must provide a low impedance path to earth so fault currents can return quickly and trip protective devices, keeping people safe and protecting equipment. For hangar deck certified power grounds, the current standard sets a maximum earth resistance of twenty-five ohms. Measurements should be below this value to meet the requirement; if the reading is higher, the grounding system needs improvement (more low-resistance paths, better connections, etc.). This twenty-five-ohm limit is chosen as a practical safety threshold.