The Solis OV-G-V01 error means your inverter measured the mains voltage at its own AC terminals above the first overvoltage stage in its grid-code settings, and shut itself down. Under the current UK G98 and G99 defaults that first stage is about 262.2 volts with a one-second trip. The 253 volt figure you may have seen quoted is the statutory supply ceiling; the inverter’s protection stages sit above it on purpose, so ordinary voltage rise and measurement tolerance do not cause nuisance trips. The trip is normally a real voltage problem on your supply rather than a broken inverter, and it is often something your Distribution Network Operator has a legal duty to correct, not something you should try to tune out by changing the inverter’s protection.
An overvoltage trip is the inverter doing its job. It is required to stop generating when the local voltage is already too high, so it does not push an over-stressed network higher still. The useful questions are which of the OV-G-V codes you actually have, whether the high reading is coming from the grid or from your own cabling, and what to write down before you phone anyone.
Jump to what you need:
- What the error means
- Which OV-G-V code you have
- Grid problem or your setup
- What to log first
- What not to touch
What does the Solis OV-G-V01 error mean?
OV-G-V is Solis shorthand for over grid voltage. The “01” is the specific stage: the grid voltage rose above the first-level overvoltage limit set by your inverter’s grid code, so the inverter disconnected to protect the network and itself. It is an AC-side reading taken at the inverter’s own terminals, not a fault in the panels or battery.
Solis defines the four over grid voltage codes separately, and telling them apart is the first useful step. OV-G-V01 is a breach of the grid code’s first-level (stage one) overvoltage limit, about 262.2 V with a one-second trip under current UK defaults. OV-G-V03 is different: it is a breach of the 10-minute average limit, which in UK use lines up with the statutory 253 volt ceiling. If you know which code you have, you already know whether the inverter reacted to a fast stage-one trip or to a sustained high voltage.
OV-G-V01 to OV-G-V04: which code you actually have
The number after OV-G-V tells you what the inverter tripped on. These are Solis’s own definitions. The exact trip voltages depend on the grid code the inverter is set to, which in the UK is the G98 or G99 protection schedule.
| Code | What Solis says it means | What it tells you |
|---|---|---|
| OV-G-V01 | Grid voltage above the grid code’s first-level overvoltage limit | The first (stage-one) overvoltage limit. Under current UK G98/G99 defaults this stage is about 262.2 V with a one-second trip. |
| OV-G-V02 | Grid voltage transient above 1.35 times the rated voltage peak | A fast transient or surge, often from something switching on the network rather than steady export. |
| OV-G-V03 | Grid voltage above the 10-minute average limit | Sustained high voltage: Solis’s 10-minute average stage. In UK use it usually sits at the statutory 253 V ceiling, while the faster stages sit above it. |
| OV-G-V04 | Grid voltage above the grid code’s second-level overvoltage limit | The second (stage-two) limit, about 273.7 V under current UK defaults, tripped faster at around half a second. |
The practical read is this. A one-off OV-G-V01 or OV-G-V02 a couple of times a day usually points to an unstable or briefly high grid. Repeated OV-G-V01 clustered around the sunniest part of the day, or an OV-G-V03, points to your export raising an already-high local voltage past the ceiling. Those two patterns lead to different fixes.
A single trip costs little. Once the voltage drops back inside the legal band the inverter has to wait a set reconnection delay, tens of seconds to a few minutes under G98 and G99, then it starts exporting again on its own. The generation you lose is only the output during that pause, so an occasional trip is not worth chasing. Repeated trips through the sunniest hours are the ones that matter, because that is peak export, so each pause throws away your most valuable generation.
What counts as “too high” in the UK?
UK low-voltage supply is declared at 230 volts, with a permitted range of 10 percent above and 6 percent below. That puts the legal band between 216.2 V and 253 V. The 253 V upper figure is the number that matters for an overvoltage trip, and it is set in law by the Electricity Safety, Quality and Continuity Regulations 2002.
Those same regulations put a duty on your Distribution Network Operator to keep the voltage at your supply terminals within that band, save in exceptional circumstances. That duty is the reason a persistent overvoltage is often the network’s problem to fix rather than yours. If your incoming supply already sits near 253 V before you generate a single watt, the headroom for your own export was never there.
Your inverter’s grid-code settings are built around this limit. The 10-minute average stage lines up with the 253 V statutory ceiling, and the faster first and second overvoltage stages sit above it, about 262.2 V and 273.7 V under current UK defaults, to catch shorter excursions. When Solis reports OV-G-V01, it is telling you the measured voltage crossed that first stage.
Why your inverter sees a higher voltage than the grid
Here is the detail that explains most sunshine trips. The voltage your inverter measures is not the voltage at the substation, and not even the voltage at your meter. It is the voltage at the inverter’s own terminals, at the far end of your service and installation cable, while current is flowing.
When you export, current runs outward through that cable, and every cable has resistance. The voltage rises along the cable in proportion to the current and the resistance. So the inverter can read several volts higher than the incoming supply, and the gap grows the harder you export. This is why an OV-G-V01 so often lands at midday on a bright day: that is when export peaks, so the voltage rise across your own wiring peaks with it. Solis lists exactly this cause, alongside undersized AC cable and loose connections that add resistance and make the rise worse.
The consequence is that two houses on the same street can behave differently. A long cable run, a thin AC cable, or a poor connection adds voltage rise that is yours to fix. A supply that is already high before you export is the network’s headroom, which is the DNO’s to fix. Most real cases are a mix of the two, which is why the next step is measurement rather than guesswork.
Is it your DNO’s problem or your setup?
You can separate the two with one observation: what is the mains voltage doing when you are not exporting? Check the inverter’s displayed grid voltage early in the morning or on a dull day, with little or no generation, then again when it trips. On the inverter’s own screen the grid voltage sits on the AC or grid information page; in the SolisCloud app it is on the device detail view, and the alarm list there timestamps every OV-G-V event, so you can read the pattern without standing at the inverter.
Before you assume the network is running high, confirm the inverter is set to the correct UK grid code, G98 or G99. A factory default left in place or a wrong regional code sets a different overvoltage ceiling and is a common cause of false OV-G-V trips, especially on a system that was only just commissioned.
- High even at rest. If the voltage sits near or above 253 V with little export, the incoming supply is already high. That is a network condition the DNO has a statutory duty to address, and it is the strongest case to raise with them.
- Fine at rest, climbs only under export. If it is comfortably mid-band at rest and only crosses the limit when you export hard, you are seeing voltage rise across your own cabling combined with limited network headroom. Cable size, run length and connection quality are worth checking, and the DNO may still need to lower the supply voltage to give you room.
- Only brief, occasional spikes. One or two short OV-G-V01 or OV-G-V02 events a day, unrelated to your export, usually reflect an unstable grid or a nearby load switching. These are worth logging but rarely need action on your side.
One honest caveat before you build a case on the inverter’s number: the inverter’s own voltage reading can drift from reality if its internal sampling is off. Solis flags this, and it is why a separate measurement at the meter or supply cut-out, taken by a competent person, carries more weight than a screenshot of the display. If the two disagree, that gap is itself a finding worth reporting.
What to log before you call anyone
A DNO or installer can act far faster on a short table of evidence than on “my inverter keeps switching off”. Voltage complaints are often assessed against the 10-minute average and against a period of monitoring, so a record over several days is worth more than a single reading. Keep a simple log every time it trips.
| Record | Why it matters |
|---|---|
| Date and time of the trip | Shows whether trips cluster around midday export or happen at random. |
| Weather and roughly how sunny | Links trips to high generation, which points at voltage rise. |
| Exact code (OV-G-V01, 02, 03 or 04) | Separates a fast stage-one trip from a sustained 10-minute overvoltage. |
| Inverter’s displayed grid voltage at the trip | The number the inverter acted on. |
| Your export power at the time, if shown | Confirms whether you were exporting hard when it tripped. |
| Grid voltage at rest, morning or dull day | Reveals whether the supply is high before you generate. |
| A separate meter reading at the cut-out, if a competent person can take one | Independent check against the inverter’s own display. |
| How often it happens per day | One-off versus repeated changes how seriously it is treated. |
If you have Solar Assistant, Home Assistant or the inverter’s own logging, export the grid-voltage trace for the days it tripped. A voltage plot that repeatedly touches 253 V at midday is a stronger piece of evidence than any description, and it is exactly what a DNO voltage-complaint team needs to see.
What not to do: leave the protection thresholds alone
The tempting fix is to raise the overvoltage limit, or switch the grid code to a region with a higher ceiling, so the inverter stops tripping. Do not do this. The overvoltage protection is a required safety function, and its settings are fixed by the G98 or G99 grid code your connection was notified or approved under.
Changing them does not make the voltage safe. It lets your inverter keep pushing power into a network that is already at its legal limit, which is the exact condition the protection exists to prevent, and it puts your installation outside the settings your DNO agreement relies on. If a persistent overvoltage is real, the answer is to get the supply voltage brought back into range, not to widen the window in which your inverter ignores it. Setting the correct UK grid code in the first place is fair game, and a wrong grid code is a genuine cause of false trips; deliberately loosening a correct one is not.
Two things Solis does support are worth knowing. Many models offer an over-voltage response, sometimes labelled a volt-watt or P(U) curve in the grid-code settings, that gently reduces output as the voltage climbs so the inverter eases back before it reaches a hard trip. A competent installer enables it inside the grid code rather than by moving the trip point, so the installation stays compliant. Improving the AC side, a larger cable or a remade connection, removes voltage rise that is genuinely yours. Neither of those touches the trip thresholds.
When to go back to your installer or DNO
Once your log shows a pattern, route it to the right party. Loose connections, cable sizing and grid-code configuration sit with your installer or a competent electrician. A supply that runs high, especially at rest, sits with your DNO as a voltage complaint under their statutory duty. Solis’s own guidance says plainly that where the measured voltage on site is high, the next step is to raise the high voltage with the utility.
When I dealt with my own DNO on a grid-connection change, the admin replies often came the same day. A voltage complaint is a normal, well-worn request for them, though the investigation itself takes longer, because they usually fit a voltage logger on your supply for a week or so before they act. A clear multi-day log of your own, with dated voltage readings, is what gets it moving. When you contact them, say you are making a voltage complaint, point to the distributor’s duty under regulation 27 of the ESQCR to hold your supply within 216 V to 253 V, and send your voltage table. If the supply is out of limits they can adjust the local transformer tap or reinforce the feeder to bring it back into range.
If you find your DNO, the Energy Networks Association operator lookup maps your postcode to the right company and their fault and voltage-complaint contact.
Sources
- Solis, OV-G-V alarm (per-code definitions, causes, and advice to raise high on-site voltage with the utility).
- Solis, Solution for OV-G-V0X alarm (cable length and impedance, grid-code settings, over-voltage droop mode).
- Electricity Safety, Quality and Continuity Regulations 2002, regulation 27 (230 V declared voltage, plus 10 percent and minus 6 percent, and the distributor’s duty).
- Energy Networks Association, statutory voltage limits (the 216 V to 253 V band and the distributor’s duty).
- Engineering Recommendation G98 and G99, interface protection settings: the two-stage overvoltage defaults quoted above, about 262.2 V at one second and 273.7 V at half a second, plus the 10-minute average stage.
The next move
Note the exact code, then read the inverter’s grid voltage both when it trips and when it is quiet. If the supply is high at rest, log it over several days and take it to your DNO as a voltage complaint. If it only climbs under heavy export, have your installer check cable size and connections while you keep the same log. Whatever the pattern, leave the overvoltage protection settings as your grid code sets them, and fix the voltage instead of hiding the warning.
