NABCEP Solar Energy System Design & Installation 3

Question 1

What type of roof penetration sealant is recommended for PV mounting hardware to ensure a weatherproof installation?

Accepted Answer

Flashing kits with code-compliant waterproofing integrated into the mount

Answer

Approved flashing kits integrate waterproofing into the mount assembly, meeting roofing standards and preventing leaks around penetrations.

Question 2

A string of 10 modules each with Voc of 40V is installed in a climate with a minimum design temperature of -10°F. Using the IEC 60364-7-712 method, if the voltage correction factor at -10°F is 1.25, what is the maximum string Voc?

Accepted Answer

500V

Answer

Maximum Voc = 10 modules × 40V × 1.25 correction factor = 500V, which must not exceed the inverter's maximum input voltage.

Question 3

Which tool is most commonly used during commissioning to verify that each PV module in a string is producing power and to identify failed modules?

Accepted Answer

Thermal infrared camera

Answer

An infrared camera reveals hot spots, failed bypass diodes, and shading effects that indicate underperforming modules during commissioning.

Question 4

What is the purpose of a module-level power electronics (MLPE) device such as a microinverter or DC optimizer?

Accepted Answer

To mitigate shading and mismatch losses by independently maximizing each module's power output

Answer

MLPEs perform per-module maximum power point tracking, reducing losses caused by partial shading, soiling, or module mismatch.

Question 5

Which of the following is a key design consideration when using transformerless inverters in a PV system?

Accepted Answer

The PV array must not have a grounded conductor under NEC 690.35 conditions

Answer

Transformerless inverters typically require an ungrounded PV array because they lack galvanic isolation, and NEC 690.35 addresses ungrounded PV system requirements.

(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 3