NABCEP - Certified North American Board of Certified Energy Practitioners Specialist Electrical Component Inspection Questions and Answers

Question 1

During a visual inspection of a newly installed string inverter, which of the following findings would be the MOST immediate cause for concern and require correction before commissioning?

Accepted Answer

There is less than the manufacturer-specified clearance for ventilation around the unit.

Answer

The inverter's cooling fins are warm to the touch.

Answer

A warning label for 'PHOTOVOLTAIC POWER SOURCE' is missing from a nearby DC conduit.

Answer

The DC input and AC output conduits are run parallel to each other for three feet.

Question 2

An inspector is examining the DC combiner box for a 600V nominal system. Which of the following observations is a clear violation of standard electrical practice and the NEC?

Accepted Answer

Unused openings in the enclosure are sealed with duct tape.

Answer

The enclosure is made of a non-metallic, UV-rated material.

Answer

The fuses are rated for 600V DC and sized at 156% of the string's short-circuit current (Isc).

Answer

The equipment grounding conductor is bonded to the combiner box enclosure.

Question 3

When inspecting exposed single-conductor cables (PV Wire/USE-2) within a rooftop solar array, what is a critical installation requirement according to NEC 690.31?

Accepted Answer

Conductors must be secured and supported to prevent damage from wind and abrasion.

Answer

Conductors must be supported at least every 10 feet.

Answer

Conductors must be enclosed in metallic conduit if they are within 1 foot of the roof surface.

Answer

Conductors must be color-coded black for negative and red for positive for their entire length.

Question 4

A technician is inspecting a junction box on the back of a PV module and notices that the sealing gasket is cracked and displaced, with evidence of moisture ingress. What is the most likely consequence of this defect?

Accepted Answer

Corrosion of terminals and potential bypass diode failure.

Answer

An immediate increase in module open-circuit voltage (Voc).

Answer

A gradual discoloration of the module's front glass.

Answer

The module's frame will lose its grounding connection.

Question 5

During a commissioning inspection, you are verifying the overcurrent protection for the inverter's AC output circuit. If the inverter's maximum continuous output current is 32A, what is the minimum standard size for the back-fed circuit breaker in the main panel, per NEC requirements?

Accepted Answer

40A

Answer

30A

Answer

32A

Answer

50A

Question 6

Which of the following must be verified during the inspection of a PV system's grounding and bonding system?

Accepted Answer

All metallic components that could become energized, such as module frames and racking, are bonded together and to the grounding system.

Answer

All DC conductors are larger than the equipment grounding conductor.

Answer

The grounding electrode conductor is routed in the same conduit as the AC output conductors.

Answer

A separate grounding rod is installed for the PV array at the closest point to the inverter.