No Production After Storm Decision Tree

Why this matters

The "system stopped producing after the storm" call is one of the most common post-event service tickets and has the widest variance in actual cause. Lightning surge damage to the inverter, AC supply tripped at the load center, RSD initiator unlatched by a brief voltage anomaly, water ingress into a J-box on a roof penetration, panel impact from hail or debris, or simply the inverter waiting out a grid hold-off after the utility had its own anomaly - all present identically to the customer as "no green light on the app." A tech that jumps to inverter swap on these calls eats warranty parts cost; a tech that walks the tree finds the actual root cause and most of the time it is upstream of any inverter component. This decision tree gets the right answer in one truck roll.

Step 1 - Confirm scope through the monitoring portal

Before mobilizing, log into the inverter manufacturer's portal (Enphase Enlighten, SolarEdge Monitoring, SMA Sunny Portal, Tesla One, Fronius Solar.web). Pull:

• Last reporting timestamp - if the system stopped reporting at the storm's onset and never came back, the gateway is offline. If it stopped reporting after the storm cleared, the issue is downstream of the gateway.
• Most-recent fault codes - many inverters log the trigger that caused shutdown (Frequency deviation, Voltage deviation, Ground Fault, Arc Fault, RSD trip).
• Neighboring sites on the same utility feeder - if the contractor's other installs in the same zip code dropped at the same minute and restored later, the cause is utility-side and no on-site work is needed.

If the gateway is online and reporting zero production with a fault code, that fault code is the starting point for the rest of the tree.

Step 2 - Verify customer-side AC supply

On site, first action is the AC supply chain from the inverter back to the utility meter:

1. At the customer's main load center, find the dedicated PV breaker. Confirm it is in the ON position. Storm-related under/over voltage can trip a breaker the customer never noticed.
2. Verify the AC disconnect at the inverter is closed. Many AHJ require an external visible-blade disconnect; some customers turned it OFF themselves "to be safe during the storm" and never turned it back on.
3. Measure voltage at the inverter's AC input. Should read 240 V plus or minus 5 V split-phase. Voltage above 264 V or below 211 V is outside the inverter's normal trip window and the inverter will sit in standby waiting for the grid to return to spec.

If the voltage is wrong, that is a utility-side problem and the customer needs to call the utility, not the solar contractor.

Step 3 - Read the rapid shutdown system

PV systems on buildings installed under NEC 690.12 must include a rapid shutdown system. The most common implementations:

• DC-side optimizers (SolarEdge, Tigo, etc.) that report through the inverter
• AC-side microinverters (Enphase) where each module's microinverter shuts off when AC is removed
• DC-side initiator switches (manual or auto) that signal MLPE devices

If a lightning EMP or nearby strike voltage transient caused the RSD initiator to latch the system into safe mode, the inverter will read zero voltage at its DC input even on a clear-sky afternoon. Re-arm the initiator per the manufacturer's procedure - usually involves pressing a reset button on the initiator box, then power-cycling the inverter.

For Enphase, an AC restart at the load center re-energizes all microinverters. For SolarEdge, the inverter's P/1/0 switch toggled OFF-ON resets the SafeDC state. For Tigo TS4, the Cloud Connect device must re-handshake with all TS4s before the string energizes.

Step 4 - Inspect for surge and lightning damage

Look at the AC and DC SPDs (surge protective devices) at the inverter and at the array combiner if installed. Most SPDs have a visible indicator window - green = healthy, red = sacrificed. A red-window SPD means a surge transient reached it; the SPD did its job and is now expended. Replace before continuing.

Open the inverter cover (with the inverter de-energized and locked out). Visible burn marks, blackening, or melted insulation on internal components means lightning energy got past the SPD into the inverter. The inverter is then almost certainly damaged beyond repair - photograph everything for the warranty claim.

If the AC disconnect cabinet shows scorched contactor pads, the surge transferred through the AC disconnect to the load center. Verify the load center breakers' trip integrity and look for arcing damage at the panel busbar.

For lightning damage claims to the homeowner's insurance, document the strike location reported by the National Lightning Detection Network (NLDN) - free queries at www.lightningmaps.org or Vaisala's Strikenet service. NLDN data within a 1-mile radius and 15-minute window of the failure timestamp is typically accepted by carriers as cause-evidence.

Step 5 - Check rooftop wire management and J-boxes

After heavy rain or wind events, water can enter:

• Rooftop combiner boxes with cracked or unseated covers
• Module J-boxes where the cable strain relief has loosened
• Conduit fittings where the listed sealant has failed

Water in a J-box can cause ground faults (inverter will display GROUND FAULT or ISOLATION FAULT). Disconnect each string's MC4 pair at the combiner one at a time and watch the isolation reading after the inverter restarts. The string whose disconnection clears the fault is the string with the water ingress.

Wind damage: walk the array visually from a ladder. Look for displaced modules, missing rail clips, bent rails, displaced flashings, exposed roof underlayment, missing micros (Enphase units have been known to detach from the rail in extreme uplift events and the AC trunk holds them suspended).

Hail damage on glass modules: front-glass cracks (radial fracture pattern from impact point), back-sheet punctures, EVA delamination. Document with high-resolution photos at multiple angles for the warranty / insurance claim.

Step 6 - Specific common storm-recovery scenarios

Scenario A - utility voltage spike during storm tripped inverter into permanent fault. SolarEdge and some Fronius inverters log a "Persistent Grid Anomaly" and require a manual restart from SetApp / SolarWeb after the third consecutive auto-restart fails. Manual restart from the app clears the lockout.

Scenario B - Enphase array dark after lightning. Gateway alive, all panels dark. Check the gateway's PCS (power line communication) signal - lightning EMP can corrupt the gateway's CT calibration. Factory reset the gateway and re-pair the system. If gateway is dead, RMA with Enphase.

References

• NEC 2023 Article 690.12 Rapid Shutdown of PV Systems on Buildings
• NEC 2023 Article 690.11 Arc-Fault Circuit Protection
• NEC 2023 Article 705.12 Point of Connection
• UL 1741 Inverters, Converters, Controllers and Interconnection System Equipment, Supplements SA and SB
• IEEE 1547-2018 Standard for Interconnection of Distributed Energy Resources
• NFPA 780 Standard for the Installation of Lightning Protection Systems
• IEC 61643-11 Low-voltage Surge Protective Devices