Solis inverter logo

Solis are one of our favourite brands due to their great balance of high reliability and competitive price. Not all of the messages on this page are an actual inverter error but inverters can go wrong so these are the more common error messages.


This message indicates that the inverter has measured a high mains voltage. This is usually a genuine grid condition rather than an inverter issue.

The statutory grid voltage here in the UK is 230V ±10%, meaning that is has to be between 207V and 253V. If the inverter detects a voltage exceeding 253V then it may display the OV-G-V01 error. The inverter voltage measurement is not calibrated and therefore we need to measure the actual grid voltage and also look in the inverter menus to find the voltage that the inverter “thinks” it is. The grid voltage does fluctuate therefore these need to be taken simultaneously.

The photo to the right shows that the inverter is measuring a mains voltage of 255.5V. If a measurement taken with a multimeter or similar is much lower than this then the inverter may need to be calibrated. Sometimes a software update is necessary for this to be done. A good solar PV installer can do this for you, or alternatively you may contact Solis UK technical support. If your inverter is connected to the internet then Solis can usually do this remotely for you. They’ll need a photo of the display showing the V_Grid, and also a photo of a test instrument such as a multimeter showing the actual measured voltage at the inverter plug.

However, if the multimeter display indicates a voltage close to the inverter display then the mains voltage is too high. It will then be necessary to check the voltage at the electricity supply source (just after the meter) to ensure that the voltage is not rising across the inverter supply cables and is genuinely the supply voltage. If the supply voltage exceeds 253V here then it will be necessary to inform the local Distribution Network Operator who will send an engineer to investigate.

Fail SafeFail Safe

This is not an inverter fault. The inverter has a socket on its underside labelled ‘CT’ which can be used for monitoring export in installations that have an export limit mandated by the Distribution Network Operator. These error messages indicate that the inverter has been set up to expect a CT and that the CT is not connected to the inverter.

If your installation does have an export limit then you will need to check that the CT is plugged into the inverter properly. You are not permitted to alter this setting without the permission of your DNO so please don’t proceed with the below as you can be prosecuted should any damage or consequential losses occur.

If you are sure that your installation doesn’t have an export limit then this can easily be resolved by changing some settings deep within the inverter menu. The link below shows the instructions to get your inverter working again:

Switching off CT detection on a Solis inverter

Solis OV-bus errorOV-bus

This error message indicates an internal inverter fault and the inverter will need to be replaced. If the inverter is under warranty then contact your installer who will be able to liaise with Solis and obtain a replacement. If it is no longer under warranty then we can supply the latest Solis model from our online shop. The great news is that the connectors are identical so no electrical work will need to be done. Click here to visit our shop.