CEI Renewable Energy System Inspection 2

Question 1

When inspecting a grid-tied PV system, which device is required to disconnect the system from the utility grid during a power outage?

Accepted Answer

Anti-islanding protection relay

Answer

Anti-islanding protection is required by IEEE 1547 to prevent a PV inverter from energizing a de-energized utility line, protecting utility workers.

Question 2

NEC Article 690 requires PV source circuit conductors to be sized at what minimum percentage of the module's rated short-circuit current (Isc)?

Accepted Answer

156%

Answer

NEC 690.8(A) requires PV source circuit conductors to be sized at 125% of Isc, then multiplied by an additional 125% for continuous duty, yielding an effective 156% of Isc.

Question 3

A wind turbine installation requires a disconnect means that is capable of being locked in the open position. Where must this disconnect be located?

Accepted Answer

Within sight of the turbine or lockable in the open position

Answer

NEC Article 694 requires the wind turbine disconnecting means to be within sight of the turbine or capable of being locked in the open position to allow safe service.

Question 4

What is the primary purpose of a blocking diode in a PV string circuit?

Accepted Answer

Prevent reverse current flow from battery into the modules

Answer

Blocking diodes prevent reverse current from flowing from the battery bank back through shaded or damaged PV modules, which could cause overheating.

Question 5

During inspection of a rooftop PV array, an inspector notes the modules are mounted directly on the roof with no air gap. What is the primary concern?

Accepted Answer

Non-compliance with fire classification requirements

Answer

Modules mounted flush to the roof without an air gap may not meet the fire classification requirements of NEC 690.12 and local building codes for fire spread resistance.

(CEI) Certified Electrical Inspector Practice Test

(CEI) Certified Electrical Inspector Practice Test

CEI Renewable Energy System Inspection 2