Quick Answer
The NEC requires specific labeling for solar disconnect switches to ensure clear identification and safe operation. The labeling must include the name of the circuit, the type of circuit (e.g., PV), and any other necessary information. This labeling must be visible and accessible.
Solar Disconnect Switch Labeling Requirements
The NEC (National Electric Code) 2017 and 2020 editions require specific labeling for solar disconnect switches. According to NEC 705.12(B)(1), the labeling must include the name of the circuit, which may include the words “photovoltaic” or “PV.” The labeling must also include the type of circuit and any other necessary information, such as the capacity of the circuit in amperes. For example, a solar disconnect switch might be labeled as “120/240V PV Disconnect” or “200A PV Main Disconnect.”
Sizing Solar Disconnect Switches
When sizing solar disconnect switches, it’s essential to consider the maximum inverter rating and the total current of the solar array. The NEC recommends sizing the disconnect switch to handle 125% of the maximum inverter rating, as stated in NEC 705.12(A)(1). For example, if the maximum inverter rating is 20 amps, the solar disconnect switch should be sized to handle at least 25 amps (20 amps x 1.25). This ensures that the disconnect switch can safely handle the maximum inverter output under fault conditions.
Labeling Requirements for Main Disconnects
The main PV disconnect, which is typically the largest disconnect switch in the system, must be labeled with the system voltage and the maximum inverter rating. According to NEC 705.12(B)(2), the main PV disconnect must also be labeled with the words “main disconnect” or “main PV disconnect.” This labeling is essential for safe operation and to prevent confusion between the main disconnect and other solar disconnect switches in the system.
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