What percentage of the maximum currents calculated must overcurrent devices for PV source circuits be sized at a minimum?

The overcurrent devices for photovoltaic (PV) source circuits must be sized to a minimum of 125 percent of the maximum current calculated. This requirement is outlined in the National Electrical Code (NEC) to ensure safety and proper operation of the electrical system.

Sizing the overcurrent device at this percentage provides a buffer that accounts for potential overloads and variations in current that could occur during normal operation, such as fluctuations in solar energy output due to environmental factors. It helps to prevent nuisance tripping and allows the system to handle variations in current without compromising safety.

By adhering to this sizing requirement, the system is better protected from conditions that could lead to overheating or damage, ensuring that system components operate efficiently and reliably over their intended lifespan.