NABCEP Solar PV System Design 2

Question 1

When designing a roof-mounted PV system, what is the primary purpose of calculating the roof's dead load capacity?

Accepted Answer

To ensure the structure can support the added weight of the array

Answer

Dead load capacity determines whether the existing roof structure can safely bear the static weight of the PV modules, racking, and mounting hardware.

Question 2

A PV array has 10 modules in series, each with a Voc of 41.2V at STC. Using NEC temperature correction for a record low of -20°C, what correction factor from Table 690.7 (for -20°C with a temperature coefficient of -0.29%/°C) would be applied?

Accepted Answer

1.25

Answer

At -20°C, the NEC Table 690.7 correction factor is 1.25, accounting for increased Voc at low temperatures to ensure safe conductor and equipment ratings.

Question 3

What does the term 'temperature derating' mean in the context of PV module performance?

Accepted Answer

Reducing rated output due to elevated operating temperatures

Answer

Temperature derating reduces the expected power output of a PV module because higher temperatures decrease cell voltage and therefore total power output.

Question 4

In a string inverter system with three parallel strings of 12 modules each, what is the total number of modules in the array?

Accepted Answer

36

Answer

Three parallel strings with 12 modules per string equals 3 × 12 = 36 total modules.

Question 5

Which NEC article primarily governs the installation of photovoltaic systems?

Accepted Answer

Article 690

Answer

NEC Article 690 specifically covers solar photovoltaic systems, including wiring, equipment, and safety requirements.

(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 2