Key points from the NEC: The code requires all non-current-carrying metal parts of the solar PV system to be grounded. It specifies the minimum size of grounding conductors (more on this later). The NEC also outlines requirements for grounding electrodes (like ground rods) and how they should be installed.
Proper grounding of a photovoltaic (PV) power system is critical to ensuring the safety of the public during the installation’s decades-long life. Although all components of a PV system may not be fully functional for this period of time, the basic PV module can produce potentially dangerous currents and voltages for the life of the system.
A PV system is defined as a grounded system when one of the DC conductors (either positive or negative) is connected to the grounding system, which in turn is connected to the earth. The conductor that is grounded usually depends on the PV module technology.
The Grounding conductor of the PV array must be bonded with the building equipment ground. In addition, it is permitted to have additional grounding electrodes tied directly to the PV Grounding Conductor. Traditional: Daisy Chained Copper Wire between components. Grounding solar panel frames and mounts – Traditional Daisy Chain.
While a separate grounding electrode system is still permitted to be installed for a PV array, per 690.47 (B), it is no longer required to be bonded to the premises grounding electrode system. In PV systems with string inverters, the equipment grounding conductor from the array terminates to the inverter’s grounding bus bar.
Regardless of system voltage, equipment grounding is required on all PV systems. Appropriate bonding and equipment grounding limits the voltage imposed on a system by lightning, line surges and unintentional contact with higher-voltage lines.