At what voltage level must the PV system disconnecting means be readily accessible to unqualified persons?

The correct answer is 30 Volts. According to the National Electrical Code (NEC), a photovoltaic (PV) system disconnecting means must be readily accessible to unqualified persons if it operates at a voltage of 30 Volts or less. This is established to ensure safety, as lower voltage levels minimize the risk of electric shock or injury to individuals who may not have the technical training to handle electrical systems safely.

At voltages above this level, additional precautions and access restrictions are typically necessary to protect untrained individuals from hazards associated with higher voltages. Thus, the requirement for accessibility at the 30 Volt threshold strikes a balance between safety and usability for those who may need to disconnect the system in an emergency or for maintenance purposes. The voltage levels specified in the other choices exceed this threshold, which necessitates more stringent measures for ensuring safety around unqualified persons.