NABCEP Solar PV System Design 3

Question 1

What is the minimum required clearance between the bottom of a roof-mounted PV array and the roof surface per most manufacturer and fire code requirements?

Accepted Answer

3 inches

Answer

Most fire codes and manufacturers require at least 3 inches of clearance beneath roof-mounted modules to allow airflow and firefighter access.

Question 2

When sizing a grid-tied inverter for a PV array, what ratio of array STC DC power to inverter AC rated output is commonly called?

Accepted Answer

DC-to-AC ratio (or clipping ratio)

Answer

The DC-to-AC ratio (also called inverter loading ratio) compares total array STC wattage to the inverter's rated AC output, typically ranging from 1.1 to 1.3.

Question 3

A PV system designer calculates 8,500 kWh of annual production but the customer uses 10,200 kWh/year. What is the system's offset percentage?

Accepted Answer

83%

Answer

Offset = (8,500 / 10,200) × 100 ≈ 83%, meaning the system covers approximately 83% of the customer's annual electricity usage.

Question 4

What does MPPT stand for in solar inverter technology?

Accepted Answer

Maximum Power Point Tracking

Answer

MPPT (Maximum Power Point Tracking) is an algorithm that continuously adjusts electrical operating conditions to extract maximum power from PV modules.

Question 5

In shade analysis for PV system design, what tool is commonly used to assess shading at a specific site?

Accepted Answer

Solar Pathfinder or SunEye device

Answer

Devices like the Solar Pathfinder or Solmetric SunEye capture a hemispherical view of the sky to identify shading obstructions throughout the year.

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

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

NABCEP Solar PV System Design 3