Do Solar Manufacturers Provide Grounding Recommendations?

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Grounding Requirements from Manufacturers Many solar manufacturers provide detailed grounding requirements in their installation manuals and datasheets. For instance, the International Electrotechnical Commission (IEC) standard 62929 requires photovoltaic (PV) array grounding to be done in accordance with the local electrical codes and standards. A common grounding configuration recommended by many manufacturers is to connect the negative output of the inverter to the grounding system, and use a grounding electrode conductor (GEC) that meets the requirements of Table 250.66 of the National Electric Code (NEC).
Grounding System Design Considerations When designing the grounding system for a solar array, it’s essential to consider the array’s size, location, and type of equipment used. The grounding system should be able to handle the maximum fault current that may flow through it. According to the NEC, the grounding system should be sized to handle at least 150% of the maximum fault current. Additionally, the grounding system should be designed to minimize voltage drop and ensure that the grounding potential is within 1 volt per mile of the service entrance. For example, for a 100 kW solar array, the grounding system should be sized to handle at least 150% of the maximum fault current, which is 150% of 100 kW / 480 volts = 31.25 amps. A 4/0 grounding conductor should be used to meet this requirement.
Grounding Best Practices It’s also essential to follow best practices when installing the grounding system. These include: ensuring that the grounding electrodes are driven to a minimum depth of 8 feet; using a grounding electrode conductor that meets the requirements of Table 250.66 of the NEC; ensuring that the grounding system is bonded to the electrical panel and other electrical equipment; and using a grounding busbar to connect the grounding system to the electrical panel. By following these best practices and the manufacturers’ recommendations, installers can ensure a safe and efficient grounding system for the solar array.