How far should ground rods be spaced?

• A. 10-15 ft
• B. 5-7 ft
• C. 20-25 ft
• D. 2-3 ft

Answer: (A)

Grounding effectiveness comes from giving fault current multiple low-impedance paths into the earth. Spacing ground rods about 10–15 feet apart lets each rod act as a separate electrode while still being tied into the same grounding conductor, so the overall earth resistance drops more than if the rods were too close or too far apart. If rods are placed only 2–3 feet apart, they essentially behave as one electrode and you don’t gain much reduction in resistance. If they’re 20–25 feet apart, you risk leaving parts of the system less effectively grounded or requiring more trenching and conductor length. In practice, 10–15 feet provides a good balance between effective multiple paths and practical site layout, which is why that spacing is the recommended choice.