Wireman · PV inverter not producing: troubleshooting for electricians · 2023 NEC ·

PV inverter not producing

Grid present, AC breaker, rapid shutdown, DC input or just monitoring: find where production stops.

Before you start

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How it works

A grid-tied inverter turns DC from the array into AC that it pushes onto the utility grid. It only runs when it sees a normal grid voltage and frequency, so it shuts off in an outage (anti-islanding) and waits a few minutes after the grid returns before it starts again. It also needs enough DC voltage from the array to wake up. A “not producing” complaint is either no grid, no DC, a fault the inverter detected, or a monitoring problem where it is actually producing fine.

Step by stepFull flowchart

Every question and answer in this guide. Tap “Step by step” to walk through it.

When is it not producing, and what is the grid doing?
- Daytime, house power is onWhat does the inverter itself show?
  - Normal or producing status, app shows zeroMonitoring or communication problem
  - Dark, no lights at allTest: Measure grid voltage at the inverter’s AC terminalsExpect: About 240 V L1–L2 (208 V on a three-phase 208Y/120 service) and about 120 V each leg to ground, steady.
    - No voltage or one leg missingAC side open: solar breaker, disconnect or a leg
    - Present but high or swingingGrid voltage outside the inverter’s window
    - NormalIs the rapid shutdown initiator (the labeled PV shutdown switch, often near the meter) in the run or on position?
      - It was offRapid shutdown was turned off
      - It’s on, or there isn’t oneTest: Measure DC input voltage at the inverterExpect: Roughly the number of modules times each module’s voltage, in full sun. Several hundred volts on most residential string systems.
        Normal DC, inverter still won’t startInverter internal failure
        Zero or very low on one or more stringsArray side open: DC disconnect, fuse, connector or shutdown device
        One string lower than the othersOne string is weak
  - Fault, error or waiting statusWhat kind of fault does the screen or manual describe?
    - Grid voltage or frequency out of rangeTest: Measure grid voltage at the inverter’s AC terminalsExpect: About 240 V L1–L2 (208 V on a three-phase 208Y/120 service) and about 120 V each leg to ground, steady.
      - No voltage or one leg missingAC side open: solar breaker, disconnect or a leg
      - Present but high or swingingGrid voltage outside the inverter’s window
      - NormalIs the rapid shutdown initiator (the labeled PV shutdown switch, often near the meter) in the run or on position?
        It was offRapid shutdown was turned off
        It’s on, or there isn’t oneTest: Measure DC input voltage at the inverterExpect: Roughly the number of modules times each module’s voltage, in full sun. Several hundred volts on most residential string systems.
        Normal DC, inverter still won’t startInverter internal failure
        Zero or very low on one or more stringsArray side open: DC disconnect, fuse, connector or shutdown device
        One string lower than the othersOne string is weak
    - Low DC, no DC or PV inputIs the rapid shutdown initiator (the labeled PV shutdown switch, often near the meter) in the run or on position?
      - It was offRapid shutdown was turned off
      - It’s on, or there isn’t oneTest: Measure DC input voltage at the inverterExpect: Roughly the number of modules times each module’s voltage, in full sun. Several hundred volts on most residential string systems.
        Normal DC, inverter still won’t startInverter internal failure
        Zero or very low on one or more stringsArray side open: DC disconnect, fuse, connector or shutdown device
        One string lower than the othersOne string is weak
    - Ground fault, isolation or arc faultGround fault or arc fault detected
    - Internal or hardware faultInverter internal failure
- During a power outageNormal: anti-islanding shutdown
- Early morning, late evening or heavy overcastNot enough sun to wake up