Generator grounding: Additional ground rod is needed if the generator is more than how many feet from the building?

• A. 6 ft
• B. 10 ft
• C. 3 ft
• D. 20 ft

Answer: (A)

Grounding provides a safe, low-impedance path for fault current. If the generator is connected to a building and sits close enough, the building’s grounding electrode system already serves as the grounding path, so no extra electrode is needed. However, when the generator is more than six feet from the building, the path back to earth through the building’s ground becomes unreliable due to higher impedance. In that case, an additional grounding electrode is installed at the generator location and bonded to the generator’s grounding conductor so the generator and building share a single, effective grounding system. This keeps metal parts at safe voltages during faults and ensures a solid reference to earth.