Growatt inverter error code: what it means and what to do

Safety first

Don't open the inverter, don't touch cables or plugs and don't turn any switch on the equipment. If you smell burning, see smoke or find the inverter very hot, step away and ask for help; if there is fire, call 112.

Where to find the code

• On the inverter display or in the monitoring app, in the event list, which shows the type (Error or Warning) and the number.
• On the side label, the full model. You need the model to read the right manual.
• Photograph the display and the lights without touching.

Where the maker's lists are

The codes below are summed up, in our own words, from the troubleshooting chapters of four Growatt manuals, read on 2026-10-22: A, MIN 2500-6000TL-X; B, MIC 600-3300TL-X; C, SPH 3000-6000TL BL-UP; D, MOD 3-10KTL3-XH. The numbers and names are the manufacturer's.

Growatt separates 'Error' (a system or inverter fault, no feed-in) from 'Warning' (the unit keeps running with a problem). The same number can mean different things as an Error and as a Warning, and from one series to another, for example Error 303. Each code below says which manuals list it; always check the manual for your exact model.

Grid and temperature: what you can check

These codes point to the electricity grid or to where the inverter is. If one shows once and goes away, the inverter usually comes back by itself. If it repeats, ask for help.

• Error 300, AC V Outrange: grid voltage is outside the permitted range. If it is frequent, it is a matter for the grid operator and for the installer, who checks the AC connection and the grid standard that is set (manuals A, B, D).
• Error 302, No AC connection: the inverter does not detect the grid. You can check whether there is a power cut at home or in the area. If the solar breaker is off, don't simply switch it back on: ask for help (A, B, D).
• Error 304, AC F Outrange: grid frequency is outside the permitted range. Same approach as Error 300 (A, B, D).
• Error 408, Over Temperature: the inverter is too hot. You can look from outside to see whether anything covers the inverter or whether it is in direct sun, without touching it. If it repeats, ask for help (A, B, D).
• Warning 401, communication fault with the meter: the inverter lost communication with the energy meter or current transformer. You can check whether the app stopped showing consumption and whether there was a power cut. Checking the connections is installer work (A, B, C, D).

Codes that are installer work

For these, the cause may be in the panels, the cables, the insulation or inside the equipment. They are not for the owner: note the code, take a photo and ask for help.

• Error 200, AFCI fault: an arc was detected on the panel (DC) side. An arc is a fire risk: don't ignore it, don't touch the DC switch or connectors and ask for help (A, B, D).
• Error 201, Residual I High: leakage current is too high. There may be an insulation or wiring fault (A, B, D).
• Error 202, PV Voltage High: panel input voltage is above the maximum. Ask for help and don't touch the DC plugs (A, B, D).
• Error 203, PV Isolation Low: insulation resistance between the panels and earth is low. The measurement is installer work (A, B, D).
• Error 204, PV string reversely connected: a panel string is connected with reversed polarity. Only by trained people, never under load (D).
• Error 303: the name depends on the series. On MIN and MIC it is 'PE abnormal', on SPH it is 'Inverter L N reversed or ground failed'. There may be a neutral, earth or swapped live and neutral problem. It is work for an electrician or installer (A, B, C).
• Error 405, Relay fault: a problem with the grid relay. Ask for help (A, B, C, D).

What to send when you ask for help

• The full model, from the label.
• The type and number of the code, as shown, for example 'Error 300'.
• A photo of the display and the lights.
• When it started, whether it repeats and whether there was a power cut or building work at home.

We reply within 48 h, assess the case remotely and, if needed, with a visit, and send a written quote with the price stated before you go ahead. See also the Growatt page and equipment repair.

About this information

These are general points and don't replace the manual for your model, which prevails. The manuals give short remedies, such as 'restart, then contact Growatt'; electrical checks are installer work. Growatt is a trademark of its owner. Sol de Volta is a company independent of the manufacturer and does not speak for the brand.