If a PV system installed on a building has two separate grounding electrode systems installed, one for the DC side and one for the AC side, the two grounding electrode systems are not required to be bonded together.

• A. True
• B. False, they are required to be bonded together
• C. False, they must remain separate
• D. True, except in some cases

Answer: (B)

Bonding both grounding electrode systems so they share a common earth reference is essential for safety and proper fault clearing. When a PV installation has a DC grounding electrode system for the array and an AC grounding electrode system for the building, keeping them separate can allow a potential difference between metal parts or between equipment on the DC side and the rest of the electrical system. If a fault occurs on one side, the absence of a common reference can impede fault current from returning to its source, delaying or preventing the overcurrent protective devices from tripping and increasing the risk of shock or corrosion at connections.

By bonding the two electrode systems together at a single point, any fault, surge, or stray current is provided with a path back to the source, equalizing potential across the system and ensuring the protective devices operate as intended. In practice, this bonding is done by connecting the PV system’s grounding electrode conductor to the building’s grounding electrode conductor through a bonding jumper at a suitable location, typically near the main service equipment. This is a requirement in PV installations to maintain a safe, unified grounding system.