Quick Answer
The National Electric Code (NEC) sections 690.11 and 690.13 outline requirements for solar panel disconnects, including the types, locations, and ampere ratings of disconnects required for PV systems.
Solar Disconnect Requirements
The NEC requires disconnects to be installed for DC circuits to prevent electrical shock and other hazards. According to NEC 690.11, disconnects must be installed within sight of the PV array and near the point of connection to the inverter. The disconnect must be rated for the maximum DC output of the PV array.
Disconnect Types and Ratings
NEC 690.13 specifies the types and ratings of disconnects required for PV systems. For AC and DC systems rated up to 1,000 volts, disconnects must be rated for the maximum DC output of the PV array, but not less than 125 percent of the inverter’s DC input rating. For systems rated over 1,000 volts, the disconnect must be rated for 125 percent of the PV array’s maximum DC output.
Sizing Disconnects for Solar Panels
When sizing disconnects for solar panels, engineers must consider the maximum DC output of the PV array and the inverter’s DC input rating. For example, if a PV array has a maximum DC output of 15 amps and the inverter’s DC input rating is 12 amps, the disconnect must be rated for at least 15 amps (125% of 12 amps). This will ensure the disconnect can handle the maximum DC output of the PV array and prevent overheating or electrical shock.
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