Free NABCEP PV System Inspector Exam Practice Questions

Sample Practice Questions

Try these 10 sample questions from the NABCEP PV System Inspector Exam practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1During a final PV inspection, the combiner box has a permanent plate showing its electrical ratings and a testing laboratory listing mark. Which party ordinarily placed those product markings?

   1. A. The system installer while adding field labels
   2. B. The product manufacturer during fabrication
   3. C. The serving utility during interconnection
   4. D. The electrical inspector during final approval

   Answer: B

   Explanation: The NABCEP guide states, "These markings are placed on the product at the time of manufacture, and include listing marks from the testing laboratory, such as UL." The plate described is therefore a manufacturer marking, even though the inspector verifies it.

   Reference: NABCEP PV Installation Professional Resource Guide, v.6 — page 108, system checkout and labeling

2. 2A PV array feeding a battery charge controller has a short-circuit output current of 24 A. Under the NABCEP guide's 125% controller-current rule, what minimum continuous-current rating should the inspector require?

   1. A. 24 A
   2. B. 28 A
   3. C. 30 A
   4. D. 36 A

   Answer: C

   Explanation: The guide states, "The charge controller rated continuous current ... must be at least 125% of the PV array short-circuit output current". Applying 1.25 × 24 A gives a 30 A minimum. The 36 A option could exceed the minimum but is not the requested minimum.

   Reference: NABCEP PV Installation Professional Resource Guide, v.6 — page 37, Charge Controller Operation

3. 3Four roof modules, each with 15 square feet of exposed area, are subject to a design uplift of 50 pounds per square foot. If six roof attachments share the load equally, what uplift must each attachment resist?

   1. A. 125 pounds of uplift per attachment
   2. B. 500 pounds of uplift per attachment
   3. C. 750 pounds of uplift per attachment
   4. D. 3,000 pounds of uplift per attachment

   Answer: B

   Explanation: The NABCEP guide gives the same loading case: "If the panel is secured by six roof attachments, and if the forces are distributed equally, there would be a 500-pound force on each attachment". Four modules create 3,000 pounds total uplift; dividing by six gives 500 pounds per attachment. The other results respectively divide one module's load by six, omit the final division, or use the panel total.

   Reference: NABCEP PV Installation Professional Resource Guide v6 — page 27, roof array wind-load example

4. 4An inspector reviewing a PV permit package cannot locate the proposed inverter and disconnect positions on the property. Which package drawing should be corrected to show where the major components will be placed?

   1. A. The site diagram showing component locations
   2. B. The electrical one-line showing circuit connections
   3. C. The equipment schedule showing component ratings
   4. D. The mounting detail showing structural attachments

   Answer: A

   Explanation: The PVSI JTA directs the inspector to "Verify a site diagram includes the location of major components." The other drawings have distinct roles: electrical connections, ratings, and structural attachments, respectively.

   Reference: NABCEP Photovoltaic System Inspector Job Task Analysis — page 10, IV.A, task 1.1

5. 5Outdoor field labels on PV switchgear have faded and the engraved substrate has cracked. Under DOE's corrective action for degraded PV field markings, which treatment addresses the deteriorated labels?

   1. A. Replace each degraded label with a durable new marking
   2. B. Re-ink lettering on each cracked existing label
   3. C. Cover each cracked label with a clear protective film
   4. D. Place a duplicate label beside each cracked original

   Answer: A

   Explanation: DOE instructs, "Any labels that are showing signs of significant degradation must be replaced." It also calls for replacement labels made of durable material suited to site conditions. Re-inking, covering, or placing a duplicate beside the cracked original leaves the deteriorated marking in place instead of replacing it.

   Reference: PV System Owner’s Guide to Identifying, Assessing, and Addressing Weather Vulnerabilities, Risks, and Impacts — page 102, Corrective Action 21, Instructions

6. 6The verified maximum system voltage of a PV array is 200 V. Among charge controllers with maximum input-voltage ratings of 150 V, 200 V, 250 V, and 300 V, which is the lowest rating that meets the NABCEP guide's stated voltage relationship?

   1. A. 150 V
   2. B. 200 V
   3. C. 250 V
   4. D. 300 V

   Answer: C

   Explanation: The guide says "the charge controller maximum input voltage must be higher than the maximum system voltage". An input rating equal to 200 V does not meet that strict wording; 250 V is the lowest offered rating above 200 V.

   Reference: NABCEP PV Installation Professional Resource Guide, v.6 — page 37, Charge Controller Operation

7. 7An inspector reviews a roof PV design that relies entirely on ballast near parapets in a high-wind area. Which change aligns with DOE guidance for this wind condition?

   1. A. Add ballast at strategic roof locations to resist uplift
   2. B. Redistribute ballast at strategic roof locations to resist uplift
   3. C. Use mechanical attachments at strategic roof locations
   4. D. Increase ballast depth at strategic roof locations

   Answer: C

   Explanation: DOE warns that roof arrays in this condition "should not be fully ballasted. Use mechanical attachments at strategic locations to prevent catastrophic loss." The three ballast-only changes preserve the fully ballasted approach DOE says to avoid.

   Reference: DOE Severe Weather Resilience for Solar PV System Design — Roof Systems: Mechanical Attachments to Building Structure

8. 8A permit package shows the PV modules and inverter, but the plan reviewer cannot trace the wiring method or the connection to utility service. Which drawing contains the missing information under the PVSI task analysis?

   1. A. The structural drawing for array attachments
   2. B. The site drawing for component positions
   3. C. The electrical drawing for wiring and service connection
   4. D. The product data sheet for equipment ratings

   Answer: C

   Explanation: PVSI task 1.2 says to "Verify the electrical diagram includes information on electrical components, wiring methods, and electrical connection to the utility service." Those details belong on the electrical diagram, rather than structural, location, or product documents.

   Reference: NABCEP Photovoltaic System Inspector Job Task Analysis — page 10, IV.A, task 1.2

9. 9A PV array uses ungrounded DC circuits, and its inverter carries a general electrical rating plate. Which additional identification should the inspector verify on that inverter for this application?

   1. A. Identification for use with ungrounded PV arrays
   2. B. Identification for use with grounded PV arrays
   3. C. Identification for use with interactive PV arrays
   4. D. Identification for use with stand-alone PV arrays

   Answer: A

   Explanation: The NABCEP guide states, "Inverters or charge controllers used with ungrounded PV arrays must be listed and identified for use with ungrounded arrays." Identification for a grounded, interactive, or stand-alone application does not by itself establish identification for this ungrounded configuration.

   Reference: NABCEP PV Installation Professional Resource Guide, v.6 — page 98, ungrounded PV arrays

10. 10A battery-backed PV system uses a flooded lead-acid battery bank. The charge controller's voltage and current ratings are adequate, but its regulation profile is set for a different storage chemistry. Which profile should the inspector require?

    1. A. A flooded lead-acid battery charging profile
    2. B. A sealed gel lead-acid battery charging profile
    3. C. An absorbed-glass-mat battery charging profile
    4. D. A lithium-ion battery charging profile

    Answer: A

    Explanation: The NABCEP guide states, "Charge controllers must use appropriate charge regulation settings for the type of battery used." The installed bank is flooded lead-acid; profiles for gel, AGM, and lithium-ion storage address different battery types.

    Reference: NABCEP PV Installation Professional Resource Guide, v.6 — page 33, battery types and charge regulation