Why does my solar inverter keep disconnecting on sunny days?

The most common cause is grid overvoltage — the grid voltage in your area is running high (usually 240–253V in summer when everyone is generating). When the voltage exceeds your inverter's disconnect threshold (typically 253V), the inverter trips for safety. Check your portal voltage history to confirm. This is especially common in rural areas with long cable runs and weak grid connections.

What is the normal UK grid voltage?

UK nominal grid voltage is 230V AC. The legal operating range is 216–253V (±10% tolerance). This is called the 'statutory limits'. In many areas, especially in summer with high solar generation, the grid regularly runs in the 240–250V range. Inverters are required to disconnect if voltage exceeds approximately 253V for safety.

Can I raise my inverter's disconnect voltage threshold?

Some inverters allow adjustment of the Over Voltage Trip Point (OVTP) in the settings. However, raising it too high can cause safety issues. Most systems are set to 253V by design. If you believe your threshold is too low, contact your installer or an engineer. Raising the threshold above UK grid standards may violate your G98/G99 approval — contact your DNO if unsure.

Does lowering my export limit prevent overvoltage?

Partially, yes. High solar export causes high voltage on weak grids. Reducing your export limit reduces the power injected into the grid, which can lower the voltage and reduce overvoltage disconnects. This is a workaround, not a solution. The real solution is for your DNO to upgrade the network infrastructure. However, temporarily lowering the export limit can reduce nuisance disconnects while you arrange a permanent fix.

Should I complain to my network operator about grid overvoltage?

Yes, absolutely. Chronic grid overvoltage is a network operator problem, not a customer problem. If your inverter is regularly disconnecting due to high grid voltage, contact your DNO and raise a formal complaint. Provide voltage logs from your portal showing the problem. The DNO is responsible for maintaining voltage within legal limits. Multiple complaints drive infrastructure investment.

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Solar inverter grid overvoltage

Q: What is Volt-Watt response and how does it help?

Volt-Watt response is an automatic voltage regulation mechanism. As grid voltage rises, the inverter automatically reduces its output power instead of disconnecting. This keeps the system online while preventing the voltage from rising further. It helps prevent overvoltage disconnections and is enabled in the inverter settings. If your inverter supports it and it is currently disabled, enabling it can reduce nuisance disconnects.

Your solar system is disconnecting on sunny days — especially in summer — and the event log shows a grid overvoltage or frequency fault. This is one of the most common UK solar problems. It is caused by the grid voltage running too high when everyone is generating simultaneously, and your inverter correctly tripping for safety.

Diagnose it Book a diagnostic

Not a system fault — network issue
Very common in rural UK areas
Can be reduced with settings changes

Experiencing regular overvoltage disconnects?

A remote diagnostic session reviews your voltage history, confirms overvoltage as the cause, and recommends specific settings adjustments (Volt-Watt response, export limiting) that can reduce nuisance disconnects in your specific situation.

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13 Trustpilot reviews

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I have a GivEnergy system consisting of two batteries, two inverters and a controlling EMS (Energy Management System) which has not worked since Nov 2025. After six months I discovered Solar Tech Support, reached out to them and Ron phoned me back – how often do you get that service? Could not be more helpful – worked directly with me over the phone, outside what I would call normal working hours. Lucid explanations and we were able to discuss the issues and history using camera and email history. As this was a very rare setup, Ron was able to access an EMS expert in the field to confirm the solution. One sunny day in, I am now only paying for standing charge and a few pence for spikes in grid consumption while battery catches up with house demand.

Ian · May 2026 Trustpilot

When my GivEnergy system had an issue, I was completely left without support and had honestly lost all hope. Thankfully, I searched online and found Ron, which completely turned things around. After sending him a message, he responded incredibly fast and called me to assure me that he would get the problem fixed. I really admire his dedicated, supportive nature and his determination to find a solution. With this kind of outstanding attitude and customer service, he has absolutely secured a future customer in me.

Sree · May 2026 Trustpilot

Ron want out of is way to help, nothing was to much. He was very thorough in what he did Very knowledgeable I would highly recommend Ron and his company He did a fantastic job for me. if you have any problems, he'll do his best to help you out and resolve your problem. I wouldn't hesitate to recommend them

Dennis Brown · May 2026 Trustpilot

Ron took me through a diagnostic to confirm my GivEnergy Inverter had a fault. A common one as it turns out with the AC Inverter. As GivEnergy is defunct there is no immediate fix, aside from sourcing 2nd hand replacement. It may be that a fix becomes available over the summer which would make a lot of GivEnergy customers happy (Again)

Tony Deacon · May 2026 Trustpilot

Contacted Ron with a problem and he sorted it out quickly with no problems at all. Very knowledgeable on anything solar/ batteries. I would recommend him to anyone

Phill · May 2026 Trustpilot

I've spoken to Ron a couple of times with issues with my Givenergy installation. Such a friendly knowledge guy very highly recommended. Thank you very much for resolving my issues

michael fairhurst · May 2026 Trustpilot

Contacted Solar Tech Support in desperation. After explaining the issues I had with my system a diagnosis was made and a solution proposed. Fantastic service, even contacted a manufacturer to arrange replacement parts for me. Great communications, explained all they were doing and what I had to do, clearly and precisly. Followed up to confirm all was ok. Excellent service.

Mr Machin · May 2026 Trustpilot

After GivEnergy went into liquidation, just my luck, my battery started playing up (internal board crashed). Contacted my installer - not interested! Found Solar tech support on a Google search. Sooo glad I found this company! Ron is extremely helpful and has plenty of experience. He soon confirmed what the fault was, and helped me to get my system up and running again. Now moved my GivEnergy account to Solar tech support, and will definitely use again if I have more issues. Unusual to find such a helpful company in these times, no morons reading scripts, just direct contact with the engineer.

Keith Ballard · Apr 2026 Trustpilot

Contacted Solar Tech Support when trying to understand what my Givenergy inverter problem might be and what might be my options. Received good/honest advise which backed up my thoughts.

Hugh Speirs · Apr 2026 Trustpilot

Ron is a super star. Two months ago my GivEnergy battery failed a firmware upgrade leaving it a brick. My installer couldn't/wouldn't fix it. GivEnergy couldn't/wouldn't fix it. Then they went into administration and all hope was lost. A flurry of emails later and Ron had diagnosed the fault (failed USB flash drive, something I'd suspected) and talked me through resolving it. Two months of nothing resolved in about 3 hours. It's great to work with someone who pays attention to the details, knows that they're doing (not just following a script) and gets stuff sorted without a fuss or up-charging.

Christopher · Apr 2026 Trustpilot

I can add to the list of customers who had already 'given up' on GivEnergy due to their appalling customer service, and that was before they went into administration (their Trustpilot reviews don't lie!). So you can imagine my desperation when, having changed my ISP and my Inverter, predictably, proving to be the only device that didn't connect automatically to my new network, I found zero prospect of any customer support with GivEnergy having called in the administrators just five days earlier! The salvation came from Solar Tech Support. My IT advisor stumbled across their web site and some very helpful tips for beleaguered GivEnergy customers, as well as an offer to provide direct assistance. Nothing ventured, I decided to drop them an E-Mail, with very low expectations based on my experience of GivEnergy customer support. Within an hour Ron had responded with some pin point advice, and after a few exchanges of E-Mails he had nailed the problem, enabling the combined efforts of my IT advisor and solar installer to resolve it and reconnect my Inverter. Thank you Solar Tech Support, and Ron in particular, for coming to the aid of a deserted and despondent GivEnergy customer. Expert, razor sharp advice and first class customer service, even though I wasn't officially a customer.

customer · Apr 2026 Trustpilot

This company are a rare gem, I had a very unusual problem following a failed firmware upgrade on my GivEnergy kit. I then found out GivEnergy were in administration and had dismissed all their support staff! None of the usual fixes to try and restore my inverter comms would work, and I looked everywhere, forums, GivEnergy youtube support videos - even AI couldn't figure it out. My installer was talking about huge sums for system replacements, and being vague / evasive about if they'd even install replacement GivEnergy inverter. Enter Solar Tech Support, reassuring and knowledgeable from the very start, I've learnt loads about my solar system though the friendly chat while my engineer worked as he diagnosed the problem and figured out a fix procedure that I've not found anywhere else - amazing . If you need solar system repairs - especially if you like me have been left high and dry by GivEnergy, I cannot recommend this company enough. Give them a call.

Andy Thomas · Apr 2026 Trustpilot

I sent a message on their website regarding a problem I have on my Givenergy system. Although not supplied by Ronald, I thought it was worth an email. Within the hour on a Saturday, he phoned and we discussed the problem. He logged in remotely and gave excellent advice. I'm too far away for his on-site help but he did diagnose the problem and was happy also to chat through my thoughts about an upcoming solar/battery install I'm planning. Great bloke.... if only he was nearer!

Philip · Apr 2026 Trustpilot

Ian · May 2026 Trustpilot

Sree · May 2026 Trustpilot

Dennis Brown · May 2026 Trustpilot

Tony Deacon · May 2026 Trustpilot

Contacted Ron with a problem and he sorted it out quickly with no problems at all. Very knowledgeable on anything solar/ batteries. I would recommend him to anyone

Phill · May 2026 Trustpilot

I've spoken to Ron a couple of times with issues with my Givenergy installation. Such a friendly knowledge guy very highly recommended. Thank you very much for resolving my issues

michael fairhurst · May 2026 Trustpilot

Mr Machin · May 2026 Trustpilot

Keith Ballard · Apr 2026 Trustpilot

Contacted Solar Tech Support when trying to understand what my Givenergy inverter problem might be and what might be my options. Received good/honest advise which backed up my thoughts.

Hugh Speirs · Apr 2026 Trustpilot

Christopher · Apr 2026 Trustpilot

customer · Apr 2026 Trustpilot

Andy Thomas · Apr 2026 Trustpilot

Philip · Apr 2026 Trustpilot

Understanding UK grid voltage

Grid voltage varies throughout the day and year. Your inverter disconnects if it detects dangerously high voltage.

UK nominal voltage: 230V

The UK electrical system is designed to operate at 230V AC. This is the standard three-phase voltage used in UK homes.

Legal operating range: 216–253V

This is ±10% tolerance. Utilities are required to keep voltage within these statutory limits. Outside this range, equipment can be damaged.

Typical daytime voltage: 235–245V

In most UK areas, grid voltage sits in the 235–245V range during normal daytime hours. In summer with high solar generation, it often rises to 240–250V.

Summer peak: 245–253V

When many neighbours are generating simultaneously and the grid is weak (rural areas, long cable runs), voltage can peak at 245–253V or even higher. This is when disconnects happen.

Inverter disconnect threshold: ~253V

Most inverters are programmed to disconnect if grid voltage exceeds approximately 253V for more than a few seconds. This is a safety mechanism to protect the grid and connected equipment.

Why voltage rises in summer

In rural and semi-rural areas, the grid connection is typically a long cable run. When many solar systems are exporting simultaneously (afternoon sun), they feed power into a thin cable, raising the voltage at that location. This is Ohm's law: V = I × R.

Key insight: Grid overvoltage is not your system's fault. It is a network operator problem. When too many generators (solar systems) export power into a weak grid connection, the voltage rises. The inverter disconnect is correct and protective. The solution is for the DNO to upgrade the network — but you can reduce nuisance disconnects with settings adjustments.

What causes grid overvoltage in your area

Weak grid connection (high impedance)

Rural or semi-rural areas often have long cable runs from the substation. The cable resistance is significant. When many solar systems export power simultaneously, the voltage rise is pronounced (Ohm's law: V=IR).

Urban areas with shorter, thicker cables rarely have this problem.

High penetration of solar generation

If your street has many solar systems, they all export power simultaneously at peak generation (midday). On a weak connection, this collective export causes voltage to spike.

This is especially pronounced in affluent suburbs and rural communities where solar adoption is high.

Network operator not managing voltage

Most UK DNOs are not yet actively managing voltage to accommodate high solar penetration. They rely on reactive measures (customer complaints) rather than proactive upgrades. This is changing, but slowly.

Transformer or substation issues

Occasionally, a faulty transformer on your local substation can cause chronic overvoltage. If all neighbours report high voltage consistently, escalate to your DNO.

Neighbour loads dropping during solar peak

On an afternoon with strong sun, many households have air conditioning or heating off (good weather). Demand is low. Solar export is high. Result: significant voltage rise.

The problem is seasonal and time-dependent.

Step-by-step diagnostic

Follow these steps to confirm grid overvoltage is the cause of your disconnects.

Check the event log for overvoltage or frequency faults

Open your inverter portal and find the event log or alarm log. Search for entries containing 'overvoltage', 'over voltage', 'OVP', 'grid fault', 'frequency', or 'disconnect'. If you see many overvoltage or grid fault entries during sunny afternoons, this confirms the problem.

Check your portal voltage history graph

Most inverter portals show a voltage graph in the monitoring section. Look for a sunny day from the past week and examine the voltage trace over 24 hours.

Check for peaks above 250V, especially between 11:00–15:00. If you consistently see 250–253V peaks followed by a disconnect, this is overvoltage. Note the peak voltage — you will need this information.

Note the exact voltage at each disconnect event

Hover over the voltage graph at the time of disconnect (if your portal allows). Most disconnects occur at approximately 253V, though this varies by inverter model.

If disconnects happen at lower voltage (e.g., 248V), the inverter's Over Voltage Trip Point (OVTP) may be set too conservatively. If they happen at 253V or above, the inverter is behaving normally for UK grid standards.

Check your inverter settings for Volt-Watt response

Open your inverter configuration/settings. Look for 'Volt-Watt response', 'Volt-Watt control', 'automatic voltage regulation', 'reactive power control', or 'voltage management'.

If this feature exists and is currently disabled, enabling it can help prevent disconnects by automatically reducing output as voltage rises. Consult your inverter manual or contact the manufacturer to enable this safely.

Review your export limit setting

High voltage is often caused by high solar export. Open your inverter settings and check the export limit. If it is set to a high value (e.g., 4 kW on a 5 kW system), reducing it can lower the voltage rise and reduce disconnects.

This is a temporary workaround — the real fix is for your DNO to upgrade the network. But it can reduce nuisance disconnects while you work with the DNO.

Contact your neighbours to check if they experience the same problem

If your neighbours with solar systems also have regular overvoltage disconnects, this confirms it is a network-wide issue. If only you have the problem, it might be a local issue at your connection point.

If multiple customers report overvoltage, this is stronger justification for escalating to the DNO and requesting network upgrades.

What is Volt-Watt response and how does it help?

Volt-Watt response is an automatic mechanism that reduces inverter output as grid voltage rises, keeping the system online and preventing disconnects.

How it works

Without Volt-Watt: When grid voltage reaches the disconnect threshold (e.g., 253V), the inverter trips immediately. The system stops exporting. Customers see lost generation and frequent disconnects.

With Volt-Watt enabled: As voltage rises toward the threshold, the inverter automatically starts reducing its output power. At 250V it might export 80% of available power. At 252V it might export 50%. This gradual reduction prevents voltage from spiking above the disconnect threshold, so the system stays online.

The benefit: The inverter loses some energy output, but stays connected continuously instead of disconnecting repeatedly. Net result: more total energy exported over the day.

Important: Volt-Watt response is not enabled by default on many UK inverters. It requires manual configuration in the inverter settings. If your inverter supports it (check your manual), enabling it can significantly reduce overvoltage disconnects. However, you will lose some generation when voltage is high. This is a trade-off between continuous operation and maximum output.

How to reduce overvoltage disconnects

Step 1: Enable Volt-Watt response (if available)

This is the most effective and recommended approach. Check your inverter manual to see if Volt-Watt response, automatic voltage regulation, or similar is supported. If yes, enable it following the manual's instructions. This keeps your system online while automatically managing output to prevent overvoltage.

Step 2: Reduce the export limit (temporary workaround)

Lower export limits reduce the power injected into the grid, which lowers the voltage rise. This is not a permanent solution but can reduce nuisance disconnects while you work with the DNO.

Example: Reduce export limit from 4 kW to 2 kW. This reduces the voltage spike by approximately half, potentially preventing disconnects. The trade-off is lost export earnings.

Step 3: Contact your DNO and lodge a formal complaint

Grid overvoltage is a network operator problem. Contact your DNO (your approval letter has their contact details) and report:

Peak voltage readings from your portal (e.g., regularly 250–253V)

Dates and times of disconnects

Request they investigate voltage management in your area

Multiple customer complaints drive infrastructure investment. Document everything and follow up formally.

Step 4: Consider adding a battery

If overvoltage disconnects are severe, a battery system with smart charging can help. During high-voltage periods, excess solar can be stored in the battery instead of exported, reducing the voltage spike. This is a significant investment but addresses the root problem locally.

Working with your DNO to fix the problem

Grid overvoltage is your network operator's responsibility, not yours. Here is how to escalate effectively:

Gather voltage data

Export voltage logs from your portal for at least 1–2 weeks of sunny days. Show peaks above 250V. This is evidence of the problem.

Find your DNO contact details

Your G98/G99 approval letter lists the network operator and their contact details. Common UK DNOs: UK Power Networks (DNO for Greater London, SE, and E Anglia), Wiltshire Networks, Scottish Power, Niagara Hudson, etc.

Lodge a formal complaint

Call or email your DNO. Explain that your inverter is regularly disconnecting due to high grid voltage (attach voltage logs). Request an investigation and ask what steps they will take to manage voltage in your area.

Follow up in writing

Send a formal complaint letter (email is acceptable) to the DNO, copying their complaints department. Reference your complaint, the dates, and the voltage data. Keep copies of all correspondence.

Escalate if necessary

If the DNO does not respond or dismisses your complaint, you can escalate to Ofgem (the energy regulator). Keep documentation of all contact attempts and responses.

Solis grid overvoltage Fronius grid overvoltage SigEnergy grid protection trip GivEnergy export limit settings Export limit issues System not producing Remote diagnostic service

FAQ

Frequently asked questions

Is grid overvoltage a problem with my inverter?

No. Grid overvoltage is a problem with the network operator's infrastructure, not your inverter. Your inverter is behaving correctly by disconnecting when voltage exceeds safety limits. The problem is that the grid is not being managed properly. Multiple customers in the same area will typically experience the same issue.

Can I increase my inverter's disconnect voltage threshold?

Some inverters allow adjustment of the Over Voltage Trip Point (OVTP). However, raising it above UK grid standards (253V) can violate your G98/G99 approval and may cause grid safety issues. Do not attempt this without confirming with your DNO. Volt-Watt response is the recommended approach — it keeps the system online while preventing overvoltage.

Will enabling Volt-Watt response reduce my energy generation?

Yes, slightly. During high-voltage periods, Volt-Watt response reduces inverter output to prevent voltage rise. You will lose some generation when voltage is high. However, the alternative is a complete disconnect, which loses all generation. In most cases, Volt-Watt results in more total daily energy exported because you stay connected continuously rather than disconnecting repeatedly.

Is grid overvoltage common in the UK?

Yes, very common, especially in rural and semi-rural areas. Urban areas with strong grid connections rarely have overvoltage issues. As solar penetration increases, more areas are experiencing chronic overvoltage. This is a network-wide problem that requires DNO intervention. Reporting it formally to your network operator helps drive infrastructure investment.

Should I claim compensation for lost generation due to disconnects?

You can attempt to claim compensation from your DNO, though success is variable. Document all disconnects with timestamps and estimated lost generation. Submit the claim in writing to the network operator. If they refuse, you can escalate to Ofgem. Legal costs often exceed the compensation value, so evaluate carefully. Multiple customer claims strengthen the case for network investment.

Could a battery system help prevent overvoltage disconnects?

Yes. A battery with smart charge scheduling can store excess solar during high-voltage periods instead of exporting it to the grid. This reduces the voltage spike and prevents disconnects. You will lose export earnings but gain stored energy for evening use. This is an effective long-term solution if overvoltage is severe, though it requires significant capital investment.

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