NABCEP Commissioning 3

Question 1

Which NEC article governs the labeling requirements that must be verified during PV system commissioning?

Accepted Answer

Article 690

Answer

NEC Article 690 contains all PV-specific installation and labeling requirements, including mandatory warning labels at disconnects and combiner boxes.

Question 2

During commissioning, an insulation resistance test on a PV source circuit reads 0.5 MΩ at 500 V. How should the installer interpret this result?

Accepted Answer

Unacceptable — investigate for ground fault or damaged insulation

Answer

Industry practice requires insulation resistance values well above 1 MΩ; 0.5 MΩ suggests damaged insulation or a ground fault that must be corrected.

Question 3

What is the purpose of recording I-V curve data during PV system commissioning?

Accepted Answer

To establish a performance baseline for future degradation comparison

Answer

I-V curve measurements at commissioning serve as the baseline against which future measurements are compared to detect degradation or faults.

Question 4

A commissioning technician finds that PV module frames are not bonded to the racking system. Which code section is violated?

Accepted Answer

NEC 690.43 — Equipment Grounding

Answer

NEC 690.43 requires that non-current-carrying metal parts of PV modules and equipment be bonded to the equipment grounding system.

Question 5

When performing a functional test of a DC arc fault circuit interrupter (AFCI) during commissioning, what is the expected outcome?

Accepted Answer

The AFCI trips and must be manually reset after the test

Answer

A successful AFCI self-test or trip test causes the device to open the circuit and require a manual reset, confirming protective function.

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

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

NABCEP Commissioning 3