Practice Test Geeks(NABCEP) North American Board of Certified Energy Practitioners Solar Practice Test
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Commissioning Flashcards

7 cards from real NABCEP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Commissioning flashcards as text

  1. Which commissioning test confirms that a ground fault detection and interruption (GFDI) device on a grounded PV system is functioning correctly?

    Answer: Applying a temporary resistive ground fault and verifying the device trips

    Functional GFDI testing requires simulating a ground fault (per manufacturer procedure) and confirming the device detects it and interrupts the faulted circuit.

  2. When commissioning a battery energy storage system (BESS) paired with PV, what is verified by a 'round-trip efficiency' test?

    Answer: The ratio of energy retrieved from the battery to energy stored, confirming acceptable losses

    Round-trip efficiency measures the percentage of energy stored that can be retrieved, revealing excessive losses that may indicate cell or BMS issues.

  3. A commissioning technician notices the PV system's production monitoring shows data but the revenue-grade meter installed for incentive programs is not logging. What is the immediate next step?

    Answer: Verify communication wiring and configuration of the revenue meter separately

    Revenue-grade meters often use separate communication protocols (Modbus, pulse output) that must be independently verified during commissioning.

  4. Which voltage measurement during commissioning most directly confirms correct module-level power electronics (MLPE) operation on a DC-optimized string?

    Answer: String open-circuit voltage equal to number of modules times fixed output voltage

    DC optimizers output a fixed voltage per module; the string Voc should equal the number of modules multiplied by the optimizer's fixed output voltage.

  5. What is the significance of recording the 'commissioning irradiance level' (W/m²) at the time of performance measurements?

    Answer: It allows measured power and current values to be corrected to STC for comparison with rated specs

    Irradiance at measurement time is used to translate field measurements to STC conditions so they can be meaningfully compared to module and system specifications.

  6. During commissioning, the installer verifies conductor ampacity for the PV source circuit. Which multiplier is applied to the module's rated Isc when sizing conductors per NEC 690.8?

    Answer: 1.56× Isc

    NEC 690.8 requires conductors to be sized at 125% of Isc for continuous duty, and then an additional 125% factor is applied, yielding 1.56× (1.25 × 1.25) the module Isc.

  7. A newly commissioned rooftop system produces expected power but the utility interconnection inspection reveals the system lacks a utility-visible AC disconnect. What must occur?

    Answer: The system must be de-energized and the disconnect installed before PTO is granted

    A utility-accessible AC disconnect is required by most interconnection standards and utility tariffs; the system cannot receive PTO without it.