Paperwork for solar panel installation

I just wanted to check this with you lot to check if I am losing my mind........

I had EON install 4.6kw solar and my AC3 and 8.2 battery back in July 2021. Got a pack of around 15 documents including inverter spec sheets but more importantly a MCS certificate and an acceptance letter from the DNO on my G99 application which states my export limit of 3.68kw. Now back in October 2022 I had another 4.4kw of panels added, I did not challange the DNO on the export limit but I never got any documents (apart from the invoice) from my installer, I just chased them and they said they can not help and I need to contact my DNO to get the acceptance letter? Should their be an updated letter saying the new capacity? No MCS either...... My installer should have all this, I should not have to ask the DNO???? How mad am I?

Cheers all

THALL Check your quote and contract with the installer of the additional capacity. If it doesn't state that the installation will be MCS registered and/or a DNO preapred and submitted then you are on a sticky wicket, so to speak. If it does, then they are on the hook for it. A warning to everyone - many installers who are trying to compete on cost will often remove both from the quote and contract. If you need it, make sure it's covered in what you are paying for.

cluelesscris The contract I signed and returned difference greatly to what I actually got. As parts were in short supply I have a totally different setup and capacity. The contract says MCS cert supplied and I did have an email with another document for me to give permission for the installer to contact the DNO.

I do not need any paperwork at the moment. But if I sell the house I will need to the MCS. Plus if the DNO ever wanted to survey my home they would spot my newest solar is not limited to the 3.68kw yet, waiting on a ct clamp (been waiting since November) to come into stock.

If you still have any outstanding balance to pay, then I would continue to hold that back, until all of the paperwork is supplied. Be polite but firm with installer, and remind them that MCS membership/accreditation requires them to operate to certain rules (a copy is available on the MCS web site).

It has taken me months and months to get all of the paperwork I should have, and I'm not quite there yet - just one final electrical certificate/council notification, plus the system diagram/safety shutdown procedure document, to go.

ToothyChris Sadly I have paid in pull. It is frustrating, the work they did was really good

THALL I need to contact my DNO to get the acceptance letter?

From what you said, you gave them permission to contact the DNO on your behalf, so presumably, they did contact them and should either have or be owed the DNO agreement document. I'm not sure that any installation of this sort can be carried without DNO agreement. I get that they may be busy or the perhaps the person who dealt with the paperwork isn't there anymore; whatever their reason, IMHO, they owe you all the paperwork: Electrical Installation Certificate, Commissioning Certificate, Electrical Schematic, Commissioning and Test results, MCS Certificate and of course the DNO agreement letter/email. All apart from the last two items should be provided by any competent electrical installation company on completion of any work, the latter two for micro generation installation as well.

If it's any consolation, we paid in full as per the contract "on completion" (of commissioning) but did receive our information pack including all of the mentioned documents within about 4 weeks.

The first point wont help but I held back the last 20% of my invoice until I'd got all the paperwork - the second may help - after waiting for a while I rang the local DNO team (SP Energy in my case) and they searched for the DNO application and confirmed it was back with the installers.

FWIW, I have also contacted my DNO directly, who were happy to explain what applications had been made on my behalf, and what was happening with them. So certainly worth a go....

Just got some extra information from my installer on this. Apparently as this install was an expansion of an existing system there is no new MCS certificate, apparently this is a grey area? No new DNO acceptance letter as I was not challenging the 3.68kw export cap from the last install and I already have permission to connect to the grid with the original MCS.

Really not sure about this. I assumed when I get another AC3 installed I would need to let the DNO know as technically my generation total has changed even though it will be capped at 3.68kw.

Also means I have no official paperwork, MCS or DNO acceptance letter that shows my actual generation total. Last document I have says 9kw total from all sources, but it is now 14.48kw and will be 17.38kw when I can get a second AC3.

THALL I think it's time to call your DNO and speak to someone. Your installer may be right, in which case, written confirmation of the fact from the DNO or the installer would be good for your records. However, I suspect they may not be right. My understanding is that the DNO is entitled to know all of your installed capacity officially through the G98/99/100 process, whether your export is capped or not. The DNO would be able to confirm whether obtaining their agreement is discretionary or mandatory. If the latter, then a call from the DNO to your installer would serve well to remind them of their obligations. If the former, then posting the opinion of the DNO to this forum would increased the shared knowledge pool 👍️

Tim Its on my to do list. Will post the result when I get get an answer.

Tim Phoned my DNO. Quick and simple reply. I need a new G98 to declare my new generation capacity and an updated G100 to confirm my installer set the export cap of 3.68kw. Both documents are free but have to be generated on the uk power networks portal by my installer.

To be clear, expanding an existing PV array does need a new G98 and G100 which can only be done by a registered installer and should be free.

Seeking advice on the mcs it appears my installer is correct. It is basically to approve panels on your roof. I already have permission and certificates are for new installs. Still seems odd to me.

However, apparently my installer submitted a G100 for the install requesting a 8kw export limit and apparently that is being considered by the dno! Which is odd as previously they hit me with the 3.68kw limit. Now trying to get hold of my installer to confirm and agree a way forward.

THALL Not surprised that the DNO agreed to 3.68kW export limit but good that the installer asked for additional capacity; options in the future? The G99 for increased export limit would have been subject to a charge, presumably covered by the installer as you hadn't asked for it and they didn't mention it in their quote. If that's the cause of delay, then that makes sense as to why you seemed to be falling between two stools. Anyway, at least it's clearer now as to where the stumbling block is; with the DNO looking at the uplifted export limit. It's just a pity your installer who you seem to be happy with otherwise, hadn't told you this and given you reassurance that all the necessary certifications would be with you in time.

Can I ask a simple Q - where is the 3.68kW export limit set by the installer?

Tim The main confusion seems to be because this install was to expand an array. Though you would think replacing the inverter and adding panels would be classed as a new install rather than an expand. I am still concerned about the lack of MCS as my other MCS certificates list all the panels and roof mounting system used. But I have been told by 2 sources that an MCS is for new installs, basically permission to install on the roof.

Had another message from my installer late yesterday and they are going to redo the G98 and G100 to mention the 3.68kw export cap. But when they add a second AC3 for me when the EMS device appears they are going to put forward a new G100 listing my total generation power and see if the DNO will entertain removing the 3.68kw cap. If they are considering a 8kw export limit for me then there might be a chance..... though on paper my total export power will be 17.38kw! Though I will NEVER export that as I never export from my batteries, and my arrays are East West so peak for me will be 8kw max. Sadly the paper work you submit to the DNO does not make that clear and they only see the total possible export.

pacemaker Depends on the inverter. A GE installer can set it on the engineer page. For other inverters like my 2 solis units a CT clamp to monitor what is going out to the grid is added and the limit set on the inverter.

THALL

I have SE inverter where the panels feed, with the GE AC inverter into battery. The GE has a CT clamp, the SE doesn't have anything.

In this case is it likely set on the GE AC inverter?

pacemaker What size pv and inverter do you have?

THALL

5.5kW into a solaredge SE5000H inverter

pacemaker Whatever export limit specified is in your DNO agreement, all of the micro generation devices need to be configured to respect that limit. What that means is each will have to have a means of monitoring the premises connection to grid (usually a CT) and have the ability to reduce output to prevent export exceeding that value. We have two inverters and both have the 3.68kW limit set by Givenergy in our case (the installer "forgot"), in the inverters register. Whether one or both are exporting excess PV, they both have to reduce output to limit the export, which they do swimmingly.

I believe the 3.68kW export limit relates to the original FIT specification where as long as your PV installation was less than 3.68kW, you didn't need to limit export, as export could never exceed the installed capacity. That means that any additional installation (AC-coupled or hybrid) needs to be able to monitor export and ensure that total export to grid (FIT + additional) doesn't exceed 3.68kW. Your AC3 should have the 3.68kW limit set in it's register. A call to Givenergy will confirm what the setting is.

pacemaker Hmm I am not sure how any export is capped from the solaredge inverters but could give it a google to see. I take it your installer did not request an export higher than 3.68kw with your local DNO?

THALL

not sure yet - I haven't seen the paperwork!

pacemaker https://knowledge-center.solaredge.com/sites/kc/files/feed-in_limitation_application_note.pdf Looks like the solaredge connect to a meter and monitor directly. No extra CT clamp needed. If limited to 3.68kw export to grid the system gets pretty much instant approval from your DNO.

pacemaker 5kW Solaredge inverter? That must have been installed with a G99 application. They can take quite some time to be agreed if the aren't fast tracked (ie with a 3.68kW export limit offered by you beforehand). If they are fast tracked, the installation can proceed before the DNO agreement washes up, but if it was a full G99, then the system cannot be connected to the grid (via the consumer unit) even if they ultimately slap a 3.68kW limit on, until the DNO agreement is received. Either your Solaredge installation is capable of limiting export to 3.68kW (G99 fast track), or your installer should be in possession of the G99 agreement from the DNO with a 5kW limit. If neither of these is the case, your installer is taking a punt that the DNO will agree to what they have done for you.

Tim So you need a G99 if the equipment is capped or not? Could they not do a G98 and a G100 to show generation capacity and evidence it is capped? Because at the moment my 8kw inverter is not actually capped and I am not aware of any G99 application by my install, the DNO did not mention one yesterday either :-( Just a G98 and G100 with wiring schematic was needed. I know unless the dno come and survey they wont know for sure, but at the same time I do not want to get into any trouble or possible fine situation. I am trusting everyone is doing the right thing.

THALL I had a spat with @dragon2905 a few months ago. We were both determined we were right and it turns out we both were but I think we both learnt a lot about the process. As I recall, if your installation has a maximum potential output of 16A/phase or less, then a G98 is required which is simply notification to the DNO that a micro generation installation of less than 16A/phase has taken place. ie it can be done retrospectively, but does need to be done.

If your installation is greater than 16A/phase but each item is type tested to G98 (eg you could have two AC3s or two HY3.6s) and the total output will be limited to 16A/phase, then you can apply for a fast track G99. The fast track G99 is in essence also a notification of the installation with a potential capacity greater than 16A/phase but that the export will not exceed 16A/phase. This has to be submitted before the system is connected to the grid (ie consumer unit) but does not need to have DNO agreement before the system is commissioned. A full G99 is when you have installed capacity greater than 16A/phase which is type tested to G99 (eg HY5 or multiple HY5s in our case or 8kW Solaredge in your case). The DNO must agree to the proposal before the installation is connected to the grid. They may agree an export limit in excess of 3.68kW (ie 16A), but more commonly, they will just put the 3.68kW limit on and be done with it.

Both G98 and G99 connection guidelines are being superseded for installations beyond April this year by G100 which serves the same purpose as the old guidelines with a few extra tweaks.

AFAIK, whatever you have installed, you should be in possession of DNO agreement(s) under G98/G99 or G100 which reflects the entire micro generation installation, irrespective of who installed it. eg if you had an original FIT system ten years ago, you should have a G98 for that (actually it might have been G54 or something back then). If you then had an AC3 fitted, you should have another G98 that reflects both the FIT and AC3 installation. If you had an HY5 with additional PV, you should have a G99 (fast track or full) that reflects all of the installed capacity. The same will be the case for G100 for installations completing after April. All the existing Givenergy inverters have been type tested to G98 or G99, depending on their output (<16A or >16A) and the new ones are type tested to G100.

As long as you employed a "competent contractor" to do the installation work, you can't be liable for the apparent lack of DNO agreement. The competent contractor should be complying with all the regulations whether it's to do with electrical certification or DNO requirements. You're paying for them to do the work because you (and me) aren't competent to know what the requirements are. I'm sure they have done all the right things, they just haven't told you yet. Maybe with all the changes you're proposing to do, they're waiting until it's all finished before they notify the DNO.

The key thing is that it's going to be easier to sort out the relevant certifications now rather than when the house comes to be sold and you are delayed by getting paperwork sorted.

Tim Well, I am going to keep chasing. But based on what you just said I am interested as to why the dno guy did not mention a g99 for my 8kw inverter. I am sure (this is where I could be wrong) he said a G100 application had been made. But as my second AC3 will not go in until after April (whenever the EMS device is available) then a new G100 has to be done to list total generation and agreed export amount. I expect the DNO will eventually reject it and cap me to 3.68. Would be nice if they don't know, I have registered interest in Octopus Flux, if my export is capped I can only export 30 ish kw a day from my pv which will be a shame as I think my current pv will generate over 60kw a day in June.

THALL why the dno guy did not mention a g99 for my 8kw inverter

Do they know about it?

Tim Apparently so. Just had an email from them 2 minutes ago. They did submit a G99 which would increase my export to 8kw if approved even though my equipment totals 13.48. I dunno, just going to chase in a few weeks if I do not here anything. Then repeat in a few months for the second AC3...

Quote
"I have replied to the original email that was sent to us in January that you mentioned, to this i have attached the G99 for the 8kw inverter as this was miles easier for us that starting all over again with a G98 (as they would only come back and decline this anyway) I do not have high hopes they will approve this from the information that you gave me yesterday, however we will see what they say and we can come and limit whatever we need to once they reply. A very easy and common thing for us to do, i will keep you updated once i have a reply"

I think a lot of the confusion arises from use of the same terms (G98, G99 and G100) for different aspects of both the UK Solar PV Certification schemes and DNO application process. Or perhaps it is only the terms being used incorrectly/inadequately by the installers (and within discussions on forums)?

G98 (formerly G83) and G99 are Certification types - meaning that the Inverter has been tested (or the adequate information from the supplier to support this) for approval under the UK schemes.

The G100 is also a Compliance Certificate which, I believe, the manufacturer has provide for their Inverters and other manufacturers of other electrical equipment also have to provide for things such as meters etc.

Then just to add to the confusion there is also a G100 Export Limitation Certification

Then there are also G98 (used to be G83) and G99 DNO Application processes.

I think the G100 (formerly G59?) DNO Application..... is related to Commercial installs.

This is the best explanation of the DNO application process I have seen so far; https://www.gov.uk/government/publications/register-energy-devices-in-homes-or-small-businesses-guidance-for-device-owners-and-installation-contractors/register-energy-devices-in-homes-or-small-businesses-guidance-for-device-owners-and-installation-contractors

This is the best explanation of the DNO application process I have seen so far;

THALL

I just wanted to check this with you lot to check if I am losing my mind........

I had EON install 4.6kw solar and my AC3 and 8.2 battery back in July 2021. Got a pack of around 15 documents including inverter spec sheets but more importantly a MCS certificate and an acceptance letter from the DNO on my G99 application which states my export limit of 3.68kw. Now back in October 2022 I had another 4.4kw of panels added, I did not challange the DNO on the export limit but I never got any documents (apart from the invoice) from my installer, I just chased them and they said they can not help and I need to contact my DNO to get the acceptance letter? Should their be an updated letter saying the new capacity? No MCS either...... My installer should have all this, I should not have to ask the DNO???? How mad am I?

Cheers all

Sorry late to the party. Did you have an inverter installed to go with those panels?

I suspect that if you only had panels installed there is no requirement to amend or update the DNO as you are still export limited with your existing inverter/battery setup.

If you DID have another inverter installed then I would expect that to be classed as a new and separate installation which would require DNO approval....

Tim

Both G98 and G99 connection guidelines are being superseded for installations beyond April this year by G100 which serves the same purpose as the old guidelines with a few extra tweaks.

Oh god why do they keep changing it......?

I guess a single application potentially makes everything more simple but presumably they will have a 1/2/3 (A/B/C?) process to mirror what currently exists??

Wonder what changes will take effect for the other items that need approvals - EV Chargers, Heat Pumps, Wind Generation etc............?

THALL

I know ours is capped to 3.68 but I'm damned if I can find any mention of it in the Dashboard or Inverter settings...

Tim
Yes Solar Edge can be export limited.
https://midsummerwholesale.co.uk/pdfs/solaredge-g100-cert.pdf

Most brands Hybrid Inverters should be able to be export limited. Search G100 + Inverter Brand should provide decent results.

Just have to be careful of the many "Off Grid Chinese" Brands that technically do not have to G98/G99 (G100 going forward?) compliance.

dragon2905

Yes the inverter was changed from a 2kw unit to an 8kw. But a G99 has gone in anyway.

On GE kit apparently the export cap is on the engineer screen or GE support can set it. That is all I know.

When my second AC3 is installed I know a new set of applications will need to be done. When EON did their application for my 4.6kw pv array and 3kw ac3 install their application letter shows total pv and battery inverter power but they rounded it down. So their application was for 9kw total which was rejected and capped at 3.68. It should of been 9.98kw.

So current setup, 3kw ac3 not capped. 5kw solis capped at 3.68kw, 8kw solis not currently capped until the G99 comes back. It's a laugh isn't it :-)