NABCEP Electrical Component Inspection 2

Question 1

During a PV system inspection, you notice the output circuit conductors are routed through metal conduit with no separation from the grounding electrode conductor. What is the primary concern?

Accepted Answer

Induced currents may cause heating in the metallic conduit

Answer

Routing current-carrying conductors through metal conduit without including the return conductor can induce eddy currents in the conduit, causing heating.

Question 2

A technician inspects a string inverter and finds the DC input voltage is 15% above the inverter's maximum rated input voltage. What is the most likely cause?

Accepted Answer

Ambient temperature is unusually low, increasing Voc

Answer

Cold temperatures increase PV module open-circuit voltage (Voc), which can exceed inverter maximum DC input ratings if temperature correction was not applied during design.

Question 3

When inspecting a ground-mounted PV array, you observe rust staining on the mounting rails below the module clamps. What does this most likely indicate?

Accepted Answer

Galvanic corrosion between dissimilar metals at the clamp interface

Answer

Rust staining at clamp interfaces typically indicates galvanic corrosion caused by contact between dissimilar metals such as aluminum rails and steel fasteners without proper isolation.

Question 4

An inspector finds that the AC disconnect is labeled with a voltage rating of 240V but is installed on a 208V three-phase system. What is the appropriate finding?

Accepted Answer

This is acceptable since 240V exceeds 208V

Answer

Electrical equipment may be used at voltages at or below its voltage rating; a 240V-rated disconnect is acceptable on a 208V system.

Question 5

During a commissioning inspection, you identify that the PV source circuit fuses are rated at 20A but the module's maximum series fuse rating (Isc × 1.25 × 1.25) calculates to 15A. What action is required?

Accepted Answer

Replace the fuses with properly sized 15A fuses

Answer

Overcurrent protection devices must not exceed the module's maximum series fuse rating to protect module wiring and cells from reverse current damage.

(NABCEP) Certified North American Board of Certified Energy Practitioners Specialist Practice Test

(NABCEP) Certified North American Board of Certified Energy Practitioners Specialist Practice Test

NABCEP Electrical Component Inspection 2