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Usually self-clears

Growatt Error 300: AC Voltage Out of Range

Updated June 2026 · Reviewed for technical accuracy · ~3 min read

Error 300 (often shown as "AC V Outrange") means the grid voltage your Growatt is seeing has drifted outside the allowed working range, so the inverter disconnects to protect itself and the grid. It is one of the most common Growatt errors, and it is usually a grid-side issue that clears on its own when the voltage settles.

Grid, your wiring, or a setting?

  • Grid voltage genuinely too high or low. When the utility voltage swings out of range, the inverter trips. This is the most common cause and it self-corrects.
  • Voltage rise on a long or thin AC cable. Under full export, a weak cable run can push the voltage the inverter reads above the limit (a common cause of daytime Error 300).
  • A voltage-protection setting that is narrower than your local grid actually runs.

How to handle it

  1. Wait for it to clear. A brief, occasional Error 300 when the grid swings is normal; the inverter reconnects automatically.
  2. Notice the pattern. If it happens mostly at midday under full sun, that points to AC cable voltage rise rather than a passing grid event.
  3. Check the AC connection. A loose or undersized AC cable raises the voltage the inverter sees. This is a job for your installer to verify.
  4. The voltage range can be adjusted. An installer can widen the protection range within what your grid code allows, using the ShinePhone or ShineServer settings (or the Shinebus tool). Do not change protection limits yourself, because they exist for safety and grid compliance.

Quick decision flowchart

Error 300 appears
↓ is it rare and brief, clearing on its own?
✅ Yes → a normal grid swing. Nothing to do.
❌ Frequent, especially at midday → likely AC cable voltage rise or a weak grid.
↓
Persistent Error 300: installer checks the AC cabling and, if appropriate, the voltage-protection range.

Related Growatt codes

Error 304, AC frequency Error 302, No AC Error 303, N-PE voltage

FAQ

My appliances work fine, so why Error 300?

Grid-tied inverters follow strict voltage limits set by the grid code, tighter than what household appliances tolerate. The inverter can trip on a swing your lights barely notice.

It only happens at midday when the sun is strongest.

That is the classic sign of AC cable voltage rise: as the inverter pushes maximum power out, the voltage at its terminals climbs. Have your installer check the AC cable size and connections.

Sources

  • Growatt inverter user manual and error-code reference (Error 300 = AC voltage out of range; adjustable voltage range via ShinePhone/ShineServer/Shinebus).
  • Growatt installer documentation.
⚠️ Safety disclaimer. Solar inverters carry lethal DC and AC voltage even when "off". This guide covers observation only. AC cabling and protection-setting changes must be done by a licensed installer in line with your grid code.