NABCEP NABCEP PV Commissioning and Maintenance Specialist 3

Question 1

What interval is typically recommended for a full preventive maintenance inspection of a commercial grid-tied PV system?

Accepted Answer

Annually, at minimum

Answer

Industry best practice and most O&M contracts specify annual preventive maintenance inspections to catch issues before they cause significant energy loss or safety hazards.

Question 2

When replacing a failed string inverter in an existing PV system, what must be verified before connecting the new unit?

Accepted Answer

DC input voltage, polarity, and AC interconnection parameters match system specs

Answer

The replacement inverter must be compatible with the system's DC voltage range, string configuration, and AC grid connection parameters to operate safely and correctly.

Question 3

A monitoring system shows a sudden 20% drop in a single string's output on a clear day. Which maintenance action is most appropriate?

Accepted Answer

Inspect that string for a shaded, disconnected, or failed module

Answer

A sudden output drop in one string on a clear day indicates a localized fault — a shaded, disconnected, or failed module — that warrants immediate physical inspection.

Question 4

What is the purpose of a torque wrench during PV system maintenance?

Accepted Answer

To tighten electrical and mechanical connections to manufacturer-specified torque values

Answer

Using a calibrated torque wrench ensures connections are tightened to the exact specifications required for safe, reliable operation without over- or under-tightening.

Question 5

Which NEC article primarily governs the installation and maintenance safety requirements for PV systems in the US?

Accepted Answer

NEC Article 690

Answer

NEC Article 690 specifically addresses solar photovoltaic systems, covering wiring, disconnects, overcurrent protection, and safety requirements.

NABCEP - North American Board of Certified Energy Practitioners Practice Test

NABCEP - North American Board of Certified Energy Practitioners Practice Test

NABCEP NABCEP PV Commissioning and Maintenance Specialist 3