Quick Answer
Utility companies typically require a few factors to be met for utility interconnection approval, including a solar array size of up to 500-750 kilowatts, a minimum of 1-2 megawatt inverters, and compliance with National Electric Code (NEC) standards. Site-specific requirements also apply, such as adequate space for inverters, wiring, and electrical equipment.
Required Electrical Infrastructure
To ensure a smooth utility interconnection, the electrical infrastructure must meet certain standards. Typically, this means a minimum of a 200-amp service entrance panel with a suitable grounding system, a dedicated circuit for the inverter connection, and a disconnect switch for the solar array. The wiring size should comply with NEC standards, such as THHN (thermoplastic-insulated, heat-resistant, and non-metallic) or THWN (thermoplastic-insulated, heat-resistant, and weather-resistant) cable.
Inverter Compatibility and Testing
When selecting an inverter, ensure it is compatible with the utility company’s requirements and local electrical grid standards. The inverter must also be listed as compliant with UL (Underwriters Laboratories) or IEEE standards. Before interconnection, the inverter should undergo testing and certification to verify its performance and safety. This typically involves a review of the inverter’s technical specifications, performance data, and compliance with utility company requirements.
Site-Specific Requirements
Site-specific requirements for utility interconnection approval often include a minimum clearance of 3-6 feet between the solar array and any obstructions, such as buildings, trees, or power lines. The solar array must also be designed to withstand local wind loads and seismic activity, as specified by local building codes. Additionally, the site must have adequate space for the electrical equipment, including the inverter, disconnect switch, and wiring.
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