CEI Renewable Energy System Inspection 3

Question 1

What is the maximum voltage permitted for a PV system installed on a one- or two-family dwelling under NEC 690.7?

Accepted Answer

600V

Answer

NEC 690.7(A) limits PV system voltage to 600V DC for systems on one- and two-family dwellings to reduce shock hazard risk.

Question 2

A rapid shutdown system (RSS) is required for PV systems on buildings. Within how many seconds must conductors outside the array boundary be de-energized after initiating shutdown?

Accepted Answer

30 seconds

Answer

NEC 690.12 requires that conductors outside the PV array boundary be de-energized to 30V or less within 30 seconds of rapid shutdown initiation.

Question 3

Which conductor color is required by NEC for the grounded conductor in a DC PV system?

Accepted Answer

White or gray

Answer

NEC 200.6 requires grounded conductors (including the negative conductor in a DC system) to be identified with white or gray insulation.

Question 4

An inspector finds a PV system with a string inverter where the output circuit conductors run through an attic space. What NEC requirement must be verified?

Accepted Answer

Conductors must be rated for the maximum attic temperature encountered

Answer

NEC 690.31 requires PV system conductors to be rated for the temperatures they will encounter, and attic spaces can reach extreme temperatures requiring high-temp rated conductors.

Question 5

What is the purpose of a combiner box in a large PV array installation?

Accepted Answer

Combine multiple PV source circuits into a single PV output circuit

Answer

A combiner box aggregates the output of multiple PV source circuits (strings) into a single PV output circuit, typically including fuses or breakers for each string.

(CEI) Certified Electrical Inspector Practice Test

(CEI) Certified Electrical Inspector Practice Test

CEI Renewable Energy System Inspection 3