To which system circuits do bonding requirements apply according to the defined standards?

The bonding requirements detailed in the National Electrical Code (NEC) are fundamentally intended to ensure safety in electrical installations, particularly for photovoltaic (PV) systems.

The correct answer highlights that bonding requirements apply specifically to solidly grounded PV system circuits over 250 volts. This is crucial because circuits operating at higher voltages carry greater risks, and proper bonding is essential in reducing the potential for electrical hazards, such as shock or fire. Bonding helps create a low-resistance path for fault currents, ensuring that protective devices can operate effectively in the event of a fault.

In the context of solidly grounded systems, the requirement emphasizes the need for ensuring that all conductive parts are bonded together to maintain electrical integrity and safety. Above 250 volts, the risk of injury or damage increases, making bonding critical for safe operation.

Understanding the specifics of the bonding requirements allows for proper compliance with safety standards in PV installations, ultimately protecting both the system and individuals interacting with it.