Solis Inverter NO-GRID Alarm and AC Breaker Tripping in Ireland: Diagnostic Guide

Key Takeaways

• The NO-GRID alarm indicates that the inverter cannot sense AC voltage at its output terminals, halting all generation.
• Check the rating of the MCB to verify whether the breaker capacity is less than recommended or suffers from thermal contact wear.
• Under Irish installation rules, an AC isolator 2 pole switching live and neutral must be installed between the inverter and consumer unit.
• Never work inside live distribution boards; isolate all power sources and hire a Safe Electric Registered Electrical Contractor.

Why is my Solis inverter showing a NO-GRID error in Ireland?

When a Solis inverter illuminates its alarm indicator and displays NO-GRID, its internal control circuitry has detected a complete loss of AC mains voltage. Because grid-tied inverters are legally required to shut down immediately upon grid loss to prevent islanding, the unit stops exporting power.

The most common real-world triggers include:

1. Local Isolation Switch Left Open: The external AC rotary isolator switch located beside the inverter has been turned off or failed internally.
2. Tripped Protection Device: The dedicated miniature circuit breaker (MCB) or residual current device (RCBO) in the main consumer unit has tripped.
3. Undersized or Fatigued Breaker: The circuit breaker trips specifically when the inverter enters power export mode.
4. Utility Distribution Outage: ESB Networks is experiencing a local network blackout in your neighborhood.

For a directory of other fault indicators, refer to our overarching guide on /ie/guides/fixes/solis-inverter-troubleshooting-ireland. If your inverter trips on high voltage rather than total grid loss, consult /ie/guides/fixes/solar-inverter-grid-voltage-trip-ireland.

How to diagnose NO-GRID and AC MCB tripping step-by-step

Follow these systematic diagnostic checks to determine whether the fault is physical, mechanical, or utility-related:

1. Inspect Physical Switches: Confirm that the AC isolator switch mounted near the inverter is in the ON position.
2. Verify Consumer Unit Breakers: Open your main domestic distribution board and inspect the dedicated solar circuit breaker. If tripped, reset it once.
3. Check Inverter Software Setting: Access the inverter menu system; also from advance setting make grid on to verify the internal relay command is enabled.
4. Confirm Generation Parameters: Take complete reading of information menu like dc1 dc2 dc3 dc4 then va vb vc or vgrid then status error and total energy.
5. Examine Historical Events: Take reading from advance info alarm messages version running messages warning messages to pinpoint the exact moment generation halted.
6. Measure Terminal Voltages: If qualified, measure phase to neutral, phase to earthing, and neutral to earthing directly from the inverter AC gland end.

Diagnosing generation onset tripping and breaker sizing

When an MCB holds closed during idle standby but trips the moment power delivery begins, technical documentation advises checking whether the MCB is tripping once the inverter comes to generation mode after start run. To isolate whether the fault is current-dependent, check power control by setting limits to 10 and 20 percent. If the inverter operates stably at 10 percent but trips at higher outputs, the breaker rating or cable sizing is defective.

Where warranty service is required, Ginlong service teams often request that technicians take an AC side tripping video after connecting or disconnecting the AC connector to document the failure mode.

Data collection for service escalation

If basic resets do not restore operation, retrieve the operating status from the front panel:

• Information Menu Audit: Take complete reading of information menu like dc1 dc2 dc3 dc4 then va vb vc or vgrid then status error and total energy.
• Advanced Diagnostic Log: Take reading from advance info alarm messages version running messages warning messages.

Providing these parameters ensures technical support can identify internal inverter relay failure versus external wiring discrepancies.

Irish regulatory requirements and isolation rules

Electrical installations in Ireland must satisfy statutory safety mandates enforced by Safe Electric and the Sustainable Energy Authority of Ireland (SEAI):

• Main Isolation Mandate: Safe Electric technical guidance notes that clause 462 2 requires that a main isolating switch be provided for every installation located within 2m of the main supply point.
• Inverter AC Isolation: Under the SEAI Code of Practice, an AC isolator 2 pole switching live and neutral must be installed between the inverter and the consumer unit.
• Dual-Supply Placard: Installations must display the mandatory warning label: "Inverter Isolate AC and DC before carrying out work".
• Grid Protection Standard: Grid-tied equipment must comply with EN50549 with Irish Protection Settings to ensure immediate decoupling if mains electricity fails.
• National Wiring Compliance: All AC and DC installation work must comply with I S 10101 and the inverter must achieve a rated efficiency of 95 percent.

If you suspect an array insulation breakdown rather than an AC fault, read our testing guide on /ie/guides/fixes/solar-pv-isolation-fault-troubleshooting-ireland.

Safety: working near distribution circuits

Working on solar AC circuits carries significant shock and arc flash risks:

• Never open distribution boards or remove terminal enclosures unless the main supply has been properly isolated.
• Always shut down the DC string isolator in addition to opening the AC breaker.
• Wait five minutes for internal capacitor banks to discharge fully.
• Do not repeatedly reset a circuit breaker that trips immediately upon re-engagement.

When to engage a Safe Electric Registered Electrical Contractor

A domestic property owner can safely verify external switch positions, check ESB Networks PowerCheck, and navigate the inverter LCD menu.

However, you must call a Safe Electric Registered Electrical Contractor (REC) if:

• The circuit breaker in your consumer unit trips immediately when reset.
• Terminal measurements show zero voltage arriving at the inverter while the rest of the house has power.
• An MCB requires replacement due to thermal wear or incorrect trip curve classification.
• Any cabling, conduit, or isolation switches exhibit physical damage or overheating.