What you will see
- Code 8 or 9 when the generator is running
- Inverter will not connect on generator but works on grid
- Fault clears by itself when grid power returns
Why it happens
A small generator speeds up and slows down as loads change, so its frequency drifts. The inverter treats this as an unsafe grid and stops.
Grid-tied inverters are not designed to sync with most domestic generators, and running them together can damage either one.
Diagram
Grid or generator
WAPDA grid
GridSteady frequency
→InverterRunning
Generator
GeneratorDrifts with load
→InverterCode 8 or 9
On-grid inverters are not designed to run from most domestic generators.
What you can check yourself
- Note whether the fault only appears on generator
- Check which source was on in the changeover at the time
- Read our article on generators with solar inverters
What not to do
- Do not connect generator output to the inverter AC side without an engineer's design
- Do not keep forcing the inverter to restart on generator
When to call us
- Measure supply frequency on grid and on generator
- Check changeover wiring so the on-grid inverter is isolated on generator
- Advise on a safe generator and solar arrangement
Generators and solar in Punjab
Many homes and factories in Faisalabad and Lahore still keep a generator for long outages. We can check how it is wired against your Sungrow inverter.
Send us
fault screenshots, your generator size, and a photo of the changeover