A No Grid Message on a solar inverter means the unit cannot detect a stable grid connection or safe grid voltage, so it disconnects to protect your solar power system. This can happen on any setup, whether you use a standard PV inverter, a hybrid inverter, or a full battery system with Lithium battery storage.
In NSW, the NO-GRID alert is common because small grid faults, voltage fluctuations, and switchboard issues can interrupt the flow of AC power between your home and the network. Sometimes the cause is simple, like a tripped circuit breaker, a faulty AC isolator, or a brief blackout in your street. Other times it points to an early inverter fault, especially when the unit logs repeated error codes or alarm codes, struggles to reconnect, or cannot synchronise its DC input voltage with the grid.
A No Grid message should not be ignored because it can signal developing inverter faults, unstable grid voltage, early AC faults, or overcurrent issues in the grid connection. A licensed solar accredited electrician should check the circuit breaker, AC isolator, and inverter hardware promptly to protect your solar power system, PV inverter, or battery system from further damage.
What Causes a “No Grid” Error?
Your main switch or solar circuit breaker has tripped
This is the most common reason a solar inverter will show a No Grid error message. When the main switch or the dedicated solar circuit breaker trips, the inverter instantly loses its AC power supply and cannot detect grid voltage.
Tripping can happen after storms, a power surge in your area, an overloaded appliance, or a faulty RCD somewhere in the switchboard. When the breaker is off, the inverter technically has no connection to the grid, so it enters protection mode to keep the system safe. This affects both grid-tied systems and hybrid inverters that operate with a solar battery system.
A tripped breaker is simple to spot, but the cause behind it is not always obvious. This is why repeatedly resetting the breaker without understanding the fault can lead to more serious inverter problems later.
Grid voltage too high (Grid Over Voltage)
High grid voltage is extremely common across NSW, especially in the Central Coast, Hunter region, Newcastle outskirts, Western Sydney, and any area with large numbers of rooftop PV systems. When the grid voltage rises above the safe operating range, the inverter disconnects itself as part of its anti-islanding protection.
This can trigger alarms such as Grid Over Voltage, AC Fault, or No Grid, depending on the brand. Voltage rise can be caused by long street runs, undersized wiring, transformer issues, or simply too many homes exporting solar at the same time.
Solar inverters are designed to shut down temporarily to prevent damage to internal components and the AC relay.
Grid under-voltage
The opposite problem can also trigger a No Grid inverter alarm. During peak evening usage or when there is a supply strain in your suburb, the grid voltage can drop below the required threshold. Inverters need stable AC voltage to synchronise with the grid, so when the voltage collapses, the inverter disconnects until the supply stabilises again.
This is why some households notice the No Grid message more often in summer when the grid is under pressure from air conditioners and high overall demand.
Phase or supply issue with Ausgrid or Endeavour Energy
Sometimes the problem is not inside your home at all. A loose neutral on the street, a pole-top transformer issue, or an outage on one phase of the supply can all cause your inverter to lose communication with the grid.
When this happens, the inverter may cycle between No Grid, AC Fault, or Waiting for Grid as it tries to detect stable voltage. This type of fault affects all PV array types and battery inverters because it interrupts the AC supply path entirely.
These issues come directly from the network provider and often line up with flickering lights, partial outages, or voltage fluctuations in the house.
Loose or damaged cabling or solar AC isolators
Damaged wiring, a loose connection, moisture intrusion in an AC isolator, or heat-damaged cabling can all cause intermittent No Grid messages. This is more common in older installations, switchboards with ageing components, or systems that have not had a solar health check for many years.
If the inverter is losing grid connection randomly throughout the day, or you hear buzzing near the switchboard, the cause may be an AC isolator or cable that needs to be inspected. Only a licensed solar electrician should check or repair these components because they involve live AC supply and MCCB or breaker protection.
Internal inverter fault
If everything in the switchboard is on, the AC isolator is stable, and there are no grid issues in the area, the No Grid fault can be caused by an internal inverter problem. This may involve the relay, the AC board, the control board, or failed internal voltage-sensing circuits.
Some brands display additional alarm codes such as AC Relay Check, Overcurrent, or PV Voltage Fault alongside No Grid when an internal fault is developing. These issues typically require inverter servicing or replacement depending on the model.
Critical Safety Warning: Do Not Keep Flipping a Tripped Breaker
If your solar inverter shows a NO-GRID error and the circuit breaker or main switch keeps tripping, stop resetting it. A tripping breaker usually means there is an AC fault or wiring issue in the switchboard, the AC isolator, or the grid connection, and forcing it back on can damage the inverter’s AC relay, control board, or other internal components.
Repeated tripping can be caused by a surge, voltage rise on the grid, overcurrent, a burnt isolator, or damaged cabling. When the breaker disconnects the AC supply, it is protecting the PV inverter, the battery system, and your home from a more serious electrical fault.
If it trips again after one reset attempt, stop touching it. A licensed solar technician needs to diagnose the inverter fault, test the AC isolator, and carry out proper inverter troubleshooting before the unit is damaged beyond repair.
When to Call a Technician
If your solar inverter keeps showing a NO-GRID or No Grid Message, it is important to have a licensed solar accredited electrician check the grid connection, grid voltage, circuit breaker, AC isolator, and switchboard, because only proper testing can confirm whether the inverter is receiving stable AC power and meeting the required grid frequency and safety standards. A technician can also inspect the PV inverter or hybrid inverter for developing inverter faults, review any alarm codes or fault codes, and make sure your battery system or Lithium battery setup is protected from hidden AC faults or grid faults that may damage the equipment.
