Renewable Energy System Inspection Flashcards

When inspecting a battery storage system using lithium-ion technology, what is the most critical thermal safety concern an inspector should document?

Answer: Thermal runaway risk and presence of thermal management or ventilation

Lithium-ion batteries are prone to thermal runaway — a self-sustaining exothermic reaction — making thermal management, ventilation, and fire detection critical inspection items.

A PV system installation uses non-metallic conduit (PVC) for underground conductors. What additional requirement applies to the equipment grounding conductor in this conduit?

Answer: An insulated equipment grounding conductor must be installed inside the PVC conduit

Because PVC conduit is non-conductive and cannot serve as an equipment grounding path, an insulated equipment grounding conductor must be pulled inside the conduit per NEC 250.118.

What is the significance of the 'open-circuit voltage (Voc) temperature coefficient' when inspecting a PV system installed in a cold climate?

Answer: Voc increases as temperature decreases, so lowest expected temperature is used to determine maximum system voltage

PV module Voc rises as temperature drops, so the lowest expected ambient temperature must be used to calculate worst-case maximum system voltage for conductor and equipment rating compliance.

During an inspection, an installer claims the PV system qualifies for the 'plug-and-play' exception under NEC 690.4(B). What is the maximum output current allowed for this exception?

Answer: 15 amperes

NEC 690.4(B) allows small PV systems with a maximum of 15 amperes output current to use listed plug-and-play connectors for simplified installation on 120V branch circuits.

An inspector is reviewing plans for a PV system where the DC-to-DC converters (power optimizers) are installed at each module. What is the main advantage these devices provide from a safety inspection perspective?

Answer: They enable rapid shutdown compliance at the module level, limiting voltage in conductors during shutdown

Module-level power electronics (MLPEs) like power optimizers can de-energize their output during a rapid shutdown event, reducing conductor voltage to safe levels and simplifying NEC 690.12 compliance.

What does NEC 690.56 require regarding the marking of interactive PV system disconnecting means at utility service equipment?

Answer: A permanent warning label indicating a second power source is present and its location

NEC 690.56 requires a permanent warning label on the utility service equipment alerting utility workers and emergency responders that a PV system is present and identifying the location of the PV disconnect.

A commercial wind energy system uses a guy-wire supported tower. What grounding requirement applies to the guy wires under NEC 694.40?

Answer: Metallic guy wires must be bonded to the tower's grounding electrode system

NEC 694.40 requires metallic guy wires and structural components of wind turbine towers to be bonded to the grounding electrode system to prevent dangerous potential differences.