A CT clamp measures the current flowing through a cable without making electrical contact. In a solar battery system it is used to measure the grid feed — the data the inverter uses to control battery charging, discharging, and export limiting.
Configuration fault · All brands
CT clamp installed wrong
A backwards or misplaced CT clamp is one of the most common solar installation faults — and the one most likely to be blamed on something else. It causes battery charging failures, incorrect portal readings, and export limiting problems.
- Affects all solar brands
- Diagnosable from monitoring data
- Often missed at installation
Not sure if this is your fault?
CT clamp errors are often misdiagnosed as battery faults or portal bugs. A remote diagnostic session can confirm the cause and walk you through the fix.
Book your free remote diagnosticWhat's included Trustpilot Google
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
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
What does a CT clamp actually do?
A CT (current transformer) clamp measures the current flowing through a cable by clamping around the outside of it — no electrical contact required. In a solar battery system, the CT is almost always installed on the main grid feed cable at the point where the house connects to the grid.
This reading is the inverter's primary source of information about what the house is doing. It uses the CT data to decide: should the battery charge or discharge? Is the house importing or exporting? Should the export limit be applied?
If the CT clamp is giving wrong data — because it is backwards, on the wrong cable, or has a loose connection — the inverter makes the wrong decisions. The battery appears not to work. The portal shows nonsense figures. And none of it is the battery's fault.
Symptoms of a CT clamp fault
Any one of these should prompt a CT clamp check.
Battery not charging on cheap rate
Timed charge is set correctly but the battery stays flat through the cheap-rate window. The inverted CT reading is suppressing the charge command.
Grid shows export at night
Your portal shows grid export figures late at night when no solar is generating and no battery is discharging. The clamp is reading import as export.
Battery discharges at wrong times
Battery discharges when it shouldn't — for example, draining overnight when demand is low. The reversed reading is triggering unnecessary discharge.
Portal power flow looks wrong
The animated power flow in your monitoring portal shows energy moving in implausible directions — house consuming solar while simultaneously exporting more than the panels produce.
Export limiting not working
Your DNO has an export limit but you are breaching it, or solar generation is being curtailed to zero even when export headroom is available.
Generation figures don't track sunlight
On installations where the CT monitors the solar circuit, a backwards clamp shows negative generation or figures that don't peak at midday on clear days.
How to diagnose it from your monitoring data
Work through these checks in order. You don't need to open any enclosures.
1
Check grid reading at night — battery idle
Open your monitoring portal late at night when the battery is idle and no solar is generating. Your house is drawing power from the grid. The portal should show a grid import figure. If it shows export, the CT clamp is backwards.
2
Watch the cheap-rate charge window in real time
If you have timed charge enabled, open the portal during the charge window. Grid import should rise noticeably as the battery charges. If it stays flat or shows export, the inverted CT reading is blocking the charge command.
3
Perform a live load test
Turn on a large known load — a kettle draws about 2,000–3,000W. Watch the grid reading in your portal in real time. It should rise by roughly the wattage of what you turned on. If the grid reading falls, stays flat, or moves by an unrelated amount, the CT clamp is backwards or on the wrong cable.
4
Check whether the solar generation reading is inverted
If the CT monitors the solar circuit rather than the grid feed, look at your historical generation data. It should peak at midday on clear days and drop to zero at night. If it shows the opposite pattern — high at night, flat during the day — the clamp is backwards on the solar feed.
5
Cross-check with a plug-in energy monitor
Plug a smart plug or energy monitor into a known appliance and compare its reading to what the portal shows. If the portal's house consumption figure doesn't move when you turn appliances on and off, the CT clamp is either on the wrong cable, has a bad connection, or has failed entirely.
What the fix looks like
Backwards clamp (most common)
The CT clamp needs to be removed and refitted so the direction arrow on the clamp points the correct way (usually towards the consumer unit, away from the grid). In many installations the clamp is accessible at the inverter end without opening the consumer unit.
The CT cable itself carries no mains voltage — only a millivolt signal. The work is low-risk if the clamp location is accessible. Some inverter brands (including GivEnergy) also have a software inversion option in the configuration settings, which can correct the polarity without physically moving the clamp.
Clamp on the wrong cable
If the clamp is on a sub-circuit rather than the main grid incomer, it needs to be physically relocated. This may require accessing the consumer unit — notifiable work that must be carried out by a qualified electrician.
In some properties, the main incomer cable is in a separate meter box or at a different location from the inverter. This can make correct CT placement genuinely difficult, and is something we regularly correct during system recovery visits.
Important: Do not open your consumer unit unless you are a qualified electrician. Even with the main switch off, the cables entering the consumer unit from the meter remain live. The CT clamp cable itself is safe, but working near live incoming cables is not.
Brand-specific notes
GivEnergy
GivEnergy portals display grid power flow clearly, making a reversed CT immediately visible. The app shows a CT direction correction toggle in advanced settings on some firmware versions. See the GivEnergy CT clamp guide for full steps.
Growatt
Growatt systems use a separate meter device (ShineWiFi or ShineLan) which includes a CT clamp. The clamp orientation arrow must face the grid side. Firmware allows software polarity correction via the ShineServer portal.
Sunsynk / Deye
Sunsynk uses CT1 and CT2 clamps — CT1 is typically the grid clamp, CT2 is the load or solar clamp. Each has its own polarity setting in the inverter menu. Backwards CT on Sunsynk is a common cause of "battery not charging on cheap rate" complaints.
Related faults and guides
FAQ
Frequently asked questions
A backwards clamp inverts the polarity of the reading — import becomes export and export becomes import. This causes battery charging failures, incorrect portal power flow, and export limiting problems. It is one of the most common installation faults we diagnose remotely.
If the clamp is accessible outside the consumer unit, a competent person can flip it. The CT cable carries no mains voltage. However if the clamp is inside a consumer unit or distribution board, this is notifiable electrical work — only a qualified electrician should access it. Some inverters (GivEnergy, Growatt) also offer software polarity correction, which avoids physical work entirely.
Run a live load test: turn on a kettle (about 2–3kW) and watch the grid reading in your portal in real time. It should rise by roughly 2,000–3,000W. If it doesn't move, the clamp is on the wrong cable, has a loose connection, or has failed.
CT clamp direction errors affect all brands that use external CTs — GivEnergy, Growatt, Sunsynk, Solis, Fox ESS, and SolarEdge all use them. GivEnergy and Growatt are the brands where we see this fault most frequently reported.
In most cases, yes. Once the CT direction is correct the inverter's power flow logic works correctly and battery charging resumes as configured. Check your system mode settings after the fix — some systems reset settings when power is cycled.
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