What type of fittings and connectors are allowed for the on-site interconnection of PV modules at the time of assembly?

The correct answer is that fittings and connectors used for the on-site interconnection of photovoltaic (PV) modules at the time of assembly must be listed. This requirement arises from safety and performance standards established by the National Electrical Code (NEC), which ensures that the components meet specific testing and safety criteria.

Listed fittings and connectors have been evaluated by a recognized testing laboratory and have passed rigorous performance and safety tests. Using listed components helps guarantee that the electrical connection can handle the operational loads and environmental conditions it may encounter, minimizing the risk of failure, fire, or electrical shock.

In contrast, unlisted fittings and connectors lack this approval, which increases the risk associated with their use. Similarly, interchangeability or exposure alone does not provide enough assurance of safety and compliance with the NEC. By ensuring that all fittings and connectors are listed, the installation adheres to industry standards, enhancing the reliability and safety of the entire PV system.