Quick Answer
Safe grounding for solar PV systems is ensured by properly connecting the negative terminal of the PV array to a grounding electrode, using a grounding conductor with sufficient ampacity and length, and ensuring the grounding system is bonded to the electrical panel and neutral point.
Grounding System Design
To design a safe grounding system for a solar PV array, follow the NEC (National Electrical Code) guidelines. The grounding conductor must have a minimum ampacity of 85% of the short-circuit current rating of the inverter, and should be sized according to Table 250.66 of the NEC. For example, for a 30 kW solar array with a short-circuit current rating of 150 A, the grounding conductor should be sized to 127.5 A (150 A x 0.85).
Grounding Connections and Bonding
The grounding connections must be made to the grounding electrode, the electrical panel, and the neutral point. Use a grounding electrode conductor (GEC) that meets the requirements of Table 250.66 of the NEC. Ensure that all grounding connections are tight and secure to prevent corrosion and ensure proper electrical conductivity. Bond the grounding system to the electrical panel and neutral point using a grounding strap or bonding jumper.
Testing and Verification
Test the grounding system using a ground fault circuit interrupter (GFCI) tester to verify that it provides a safe path to ground. Measure the resistance of the grounding system using a multimeter to ensure it meets the requirements of the NEC. Verify that the grounding system is properly bonded to the electrical panel and neutral point.
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