Quick Answer
To document grounding compliance for solar installations, record measurements of earth resistance, list the grounding system components, and verify the system meets the National Electric Code (NEC) requirements. Use a grounding grid calculator to determine the required grid size and conductor material. Keep records of inspections and testing.
Selecting a Grounding System
When selecting a grounding system for a solar installation, consider the site’s soil resistivity, which affects the system’s performance. Measure the earth resistance at multiple points using a soil resistivity test kit or an earth resistance tester, such as a GFCI or a Simpson 300. For example, if the soil resistivity is 100 ohm-meters, use a grounding grid calculator to determine the required grid size and conductor material.
Grounding System Design and Installation
Design the grounding system with a minimum of 20% spare capacity to account for future system upgrades or changes. Use a 10-gauge or larger copper conductor for the grounding grid, spaced 10 to 20 feet apart, depending on the site’s soil resistivity. Connect the solar array and inverter to the grounding grid using a direct bond, ensuring a minimum 1/4-inch overlap of the bonding material. Use a grounding clamp to connect the conductors to the grounding grid, ensuring a minimum 10% mechanical pull-out resistance.
Testing and Verification
Verify the grounding system’s integrity by testing for continuity and resistance using a multimeter or earth resistance tester. Record the results and compare them to the calculated values. Perform regular inspections to ensure the system remains compliant with NEC requirements and maintain records of testing and inspections.
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