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

Every 5 years

Answer

Only when performance drops

Answer

Every 10 years

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 inverter's color matches the original

Answer

The new inverter has a higher power rating

Answer

The warranty period is identical

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

Wait one month and compare again

Answer

Reduce the inverter's power limit

Answer

Add a new string to compensate

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

To measure module efficiency

Answer

To cut conduit

Answer

To measure wind load on racking

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 230

Answer

NEC Article 480

Answer

NEC Article 310

Question 6

During maintenance, you discover arc marks inside an outdoor DC combiner box. What should you do first?

Accepted Answer

De-energize the affected circuits and identify the cause before restoring power

Answer

Clean the marks and close the box

Answer

Replace the combiner box cover only

Answer

Log the finding for next year's inspection