Growatt Error 304: AC Frequency Out of Range
Error 304 (AC F Outrange) means the grid frequency the Growatt is seeing has drifted outside the allowed range, so it disconnected to follow grid-protection rules. Frequency is set by the utility, not by you, so Error 304 is almost always a grid-side event that clears on its own once the grid settles.
What usually causes Error 304
- A short grid frequency excursion on the utility side.
- An unstable or weak grid, more common in some regions.
- Running off a generator whose frequency drifts.
How to handle it
- Wait for it to clear. The inverter reconnects automatically once the frequency is back in range. A brief, occasional Error 304 is normal.
- Watch the frequency. Rare events are nothing to act on. Frequent Error 304 suggests an unstable supply.
- On a generator, make sure it is sized and tuned for a stable frequency.
- For persistent Error 304, contact your installer or utility about grid stability.
Related Growatt codes
FAQ
Can I do anything about grid frequency?
Not directly, it is controlled by the utility. Your role is to notice whether Error 304 is rare (normal) or frequent (worth raising with your installer or utility).
Sources
- Growatt inverter user manual and error-code reference (Error 304 = AC frequency out of range; verify grid frequency compliance, restart).
- Growatt installer documentation.
⚠️ Safety disclaimer. Solar inverters carry lethal DC and AC voltage even when "off". This guide covers observation only. Grid and generator issues should be handled by your installer, utility, or a qualified technician.