How many grounding rods are recommended to meet the grounding goal?

• A. Two rods or more
• B. One rod
• C. Three rods
• D. Four rods

Answer: (A)

To meet the grounding goal, you want a path to earth with as low resistance as possible. A single grounding rod often isn’t enough because its contact with soil is limited and soil resistivity varies by location, which can leave the impedance too high.

Using two rods or more creates multiple parallel paths for fault current, which lowers the overall ground resistance and makes the system more reliable. Two is the practical minimum that generally achieves the goal; adding more rods (three, four, or more) can further reduce impedance in tougher soil conditions or for higher fault currents.

Keep in mind that rods should be spaced apart (typically several feet, often at least 6 feet) to avoid mutual interference and to maximize their combined effectiveness as part of the same grounding electrode system. Other types of electrodes can supplement the system, but the baseline recommendation is two or more rods.