Quick Answer
Grounding pole-mounted solar arrays is not always necessary, but it can be beneficial for safety and preventing electrical hazards. In the US, the National Electric Code (NEC) requires grounding for solar installations, but specific conditions must be met. Consult local electrical codes for specific requirements.
Understanding Solar Grounding Requirements
When considering grounding a pole-mounted solar array, it’s essential to understand the NEC requirements. Section 690.43(A) of the NEC requires grounding for solar photovoltaic (PV) systems, but it applies to installations with a grounding electrode system (GES) or a grounding means connected to a grounding electrode. If your solar array is isolated from the main electrical service and not connected to a GES or grounding electrode, grounding may not be necessary.
Calculating Grounding Resistance
If you do need to ground your pole-mounted solar array, it’s crucial to calculate the grounding resistance correctly. The NEC recommends a maximum grounding resistance of 25 ohms for grounded PV systems. To achieve this, you can use a grounding rod or plate connected to a grounding cable. Use the following formula to calculate the required grounding conductor size: (GRC x 1.25) / (GRC - Rg), where GRC is the required grounding resistance (25 ohms) and Rg is the grounding resistance of the grounding electrode.
Best Practices for Grounding Pole-Mounted Solar Arrays
When grounding a pole-mounted solar array, follow best practices to ensure safety and efficiency. Use a grounding system specifically designed for solar applications and compliant with local electrical codes. Bury the grounding electrode at least 12 inches deep and 6 feet away from any electrical components. Finally, ensure that the grounding system is connected to a grounding electrode that meets the NEC requirements.
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