NABCEP Study Guide 2026

During a site assessment, performing a shading analysis is critical to identify any potential obstacles, such as trees, chimneys, or adjacent buildings, that could cast shadows on the PV array. Even partial shading can significantly diminish the energy production of an entire string of modules. Identifying these obstacles allows for optimal panel placement and accurate energy yield predictions.

Solar panels generate direct current (DC) electricity, but most home appliances and the electrical grid operate on alternating current (AC). The primary purpose of an inverter in a photovoltaic (PV) system is to convert this DC electricity into usable AC electricity. This conversion is essential for powering household devices and feeding excess energy back into the grid.

A shading analysis is an essential step during the design phase of a PV system to identify any potential obstructions, such as trees, chimneys, or adjacent buildings, that might cast shadows on the PV array. Even partial shading can significantly reduce the output of an entire string of modules. By identifying and mitigating shading, designers can optimize module placement and predict accurate energy production.

A utility interconnection agreement is a legal contract governing the technical, safety, and metering requirements for connecting a distributed generation system to the utility's distribution grid.

Cut-in wind speed is the minimum wind speed at which the rotor generates enough torque for the generator to produce useful electricity; below this speed the turbine is idle.

NEC 705.12(B) allows the supply-side connection via the 120% rule: the sum of the main breaker and solar breaker must not exceed 120% of the busbar rating, and the solar breaker must be at the opposite end.