NABCEP Solar Energy System Design & Installation 4

Question 1

What is the main advantage of a bifacial PV module compared to a monofacial module?

Accepted Answer

Ability to generate power from both front and rear surfaces

Answer

Bifacial modules capture direct irradiance on the front and reflected/diffuse irradiance on the rear, increasing total energy yield.

Question 2

Under NEC 690.12, which rapid shutdown requirement applies to residential rooftop PV systems installed after the 2017 NEC adoption?

Accepted Answer

Conductors in the array boundary must be de-energized to 30V or less within 30 seconds of initiating shutdown

Answer

NEC 690.12 (2017+) requires that within the array boundary, conductors be reduced to 30V or less within 30 seconds of rapid shutdown initiation to protect first responders.

Question 3

What is the primary reason tilt angle optimization matters more for fixed-tilt systems in high-latitude locations than in equatorial regions?

Accepted Answer

The seasonal sun path variation is greater at high latitudes, so a steeper tilt better captures low winter sun

Answer

At high latitudes, the sun's elevation angle varies dramatically between summer and winter, so optimal tilt becomes more critical to capturing adequate winter energy.

Question 4

Which NABCEP competency category specifically addresses the ability to evaluate roof structure for PV mounting load capacity?

Accepted Answer

Mechanical and Structural Design

Answer

The Mechanical and Structural Design competency covers evaluating roof and mounting structure capacity, including dead loads, live loads, and wind uplift.

Question 5

A PV system's performance ratio (PR) is calculated as what?

Accepted Answer

AC energy yield divided by the product of installed DC capacity and reference irradiation

Answer

PR = (AC energy output in kWh) / (Installed DC capacity in kWp × Reference irradiation in kWh/m²), representing overall system quality.

(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 Solar Energy System Design & Installation 4