Dillsue

Bear in mind that if the panels are facing different directions the peak install will never be peak generation. We have a 3.6kw inverter with a max specified DC input of 5.7kw but its got 8.5kw of panels hooked up that are spread over 180 degrees.

You can change a FIT system- OFGEM changed the rules a little while back☺ You can change components, add batteries and increase PV capacity. If increasing the PV capacity you only get paid for the FIT accreditted capacity. In your case if you went from 4 to 5kw you only get FIT payments for 4/5 of what you generate/export.

Workiñg for builders and LA doesnt necessarily mean competance in a domestic scenario. There are limits to how much power you can push into the grid. On a construction site or LA site there maybe a consultant that deals with the DNO months or years before your installer gets to site so they never interface with the DNO or consider constraints. In your domestic install you are trusting them to ensure compliance, but you carry the can if they haven't done things correctly. If you can't get the details off the inverter, its probably worth asking them if they have exceeded G98 limits and if they have, that a G99 is in place. If they are evasive or dont understand what you are asking, then you have your answer on their competance!!

The number of panels isn't really relevant, its the inverter capacity thats relevant. If its the installer thats telling you the number of panels is relevant then either they're not explaining things very well or they dont know what they are doing!!! There'll likely be a data plate on the inverter so you may be able to see the inverter details

Ok. If the cable is SPs then its a no no but if its yours then it might be your only option. If its a straight duct the SWA should pull back in ok, if youve got enough room not to bend it as its drawn out. Getting cable rods over 70 metres is alot of rods! I think you can blow/vac lightweight cables through ducts but not sure how successful that would be with a chunky cable in the duct already

@patp A few pointers for you. UKPN are unlikely to be interested in how many panels or the panels output youve got. What they are interested in is what your inverter can export onto the grid and thats not necessarily the capacity of your panels. Without getting permission you can export 3.68kw per phase so with your 3 phase inverter youre limited to 11kw, unless you have permission to export more. If you already have an 11kw inverter and its being replaced with a bigger one, you need permission from UKPN. If youre not bothered about that its fine, but the concern could be that your questionable installation company maybe steaming ahead with something that is technically illegal. If thats what they are doing then you might want to consider their credentials. Maybe worth finding out what they're up to as ultimately its your responsibility.

Use one of the cables in the duct to pull a draw wire in then use thd draw wire to pull the cable back together with the new data cable??

Are you sure? AFAIK rule of thumb is 4 amp per kw so 5kw is circa20amp. Likely easily handled by 2.5mm cable over half a meter, but..... If youre going to increase the RCBO rating to 32amp, youll need to increase cable size.

Almost certainly a design/installation balls up! Do you know how much youre generating at any particular time?? Without an accessible realtime indication its very difficult to schedule your usage. If you got 46 panels youve likely got quite a sizeable generation capacity and even in the winter may be generating enough to not have to worry to much about scheduling loads. Do you know what the kwp rating of the panels is?

Can you hook up the new inverter and batteries to your existing solar and keep the existing inverter for the extra PV in the future?? If the hybrid Solis is G98 limited it would save any concerns with the DNO now

Just get the trays and internal cabling installed now and do a second fix for the panels and inverter once the builder has finished. If youre under pressure to get the scaffold down you may be rushing into a full install thats not right for you technically and cost

Definitely check the back up interface is available and certified for the UK. Its been available overseas for a while but if its now certified for the UK its a fairly recent event- I think last year or so. AFAIK, Energybank is Solaredges current battery offering for new systems and connects directly to the current HD wave inverters. I think the LG batteries are now intended to be used with a storedge interface for adding batteries to older inverters. I think you can still hook up LG batteries to the current inverters but it doesnt seem to be the norm. Maybe theres a cost saving with LG batteries and Storedge interface vs energybank???

Our system isn't designed to feed the grid but export is a consequence of how weve installed things. I dont have a problem with surplus going to the grid if we're not using it.

Watched the video but without sound so don't know if they covered this, but does the vector summing only happen in real time as in export only negates the same import if the two are happening at the same time? An example would be importing 4kw on L1 and at yhe same time exporting 2 x 2kw on L2+3 so the sum would be zero. If it doesnt have to be balanced in real time, then am I right in thinking you could export 2 x 5kwh on L2+3 through an afternoon and then import 10kwh through the evening giving a sum of zero???

Another problem with using an 8kw inverter on a single phase is that youll need to get DNO permission to put more than 3.68kw on a single phase. I dont know what criteria a DNO would use to accept that set up, but I would have though they would expect you to balance the 3 phases wherever possible and would likely reject 8kw on one phase and zero on the other 2 when all 3 phases could quite easily be balanced. If I remember correctly on a G99 application one of the conditions you have to confirm is that there wont be more than a 16 amp difference between phases. I guess thats important to the grid??

Probably not but speak to youre supplier as they may have a standard fitment. I think its mentioned above that net metering is part of the smart meter spec and that's what a bit of googling suggests too. It seems a great way to avoid MCS cost and get "paid" for all your export at the same rate charged for import. Just the cost of a 3 phase upgrade to fret about but it seems a no brainer for a new build if available

No experience with 3 phase inverters but assume that a 3 phase hybrid inverter will output battery energy evenly across all 3 phases so net metering will still use the battery output to offset an equivalent import?? I assume if theres 8kw load on L1, inverter will provide 8/3 on each phase to try and meet demand on L1 leaving the shortfall on L1 covered by grid import. That import would be offset by the unused export on L2 and 3??? Is that how it works??

A manufacturer??

Plenty of 8kw 3 phase sunsynk inverters listed on the ENA type test database but the only one listed as a hybrid isnt approved so shouldn't be connected to the grid. Probably want to ask the installer about that!! It's been mentioned on here before but if the OP has a 3 phase smart meter, or can get one fitted, then they could well have net metering so its largely irrelevant how the 3 phases are loaded as import and export are offset against each other. As I understand it PV export on any phase cancels out import on any phase to give a net consumption that you get billed for. No MCS needed to get "paid" for your export at a very lucrative equivalent rate. Hopefully someone who knows about 3 phase net metering will confirm?? Another thing for the OPs spark to look into.

One from Scottish Power. Seems the pros cant even get the units right so there's no hope for the rest of us

Googling your inverter and the spec says it can operate on 3 phase. Your quote only has a single phase generation meter so did you ask for a 3 phase PV system and the supplier has made a mistake? Plenty of info on the web but make sure your looking at UK web sites!! If youre not too confident with electrics, you might be best paying your electrician to come and explain your house wiring before you go looking at PV. PV install and wiring will likley make much more sense if you have a grasp of how your house electrics work.

I dont think its a policy decision intended to make people suffer, but more a policy decision for other reasons that some people are as a consequence suffering. As we've got a climate crisis to sort out, personally Im quite comfortable with the hike in energy prices to focus the 1st world on cutting consumption.

Good on you. Its your drop that matters but most people dont realise that

No electronics knowledge needed to install or fault find on PV systems. Maybe if youre an enthusiast wanting to build your own bits and bobs but that's far from the norm. Electrics yes but no electronics No software knowledge needed either. Configuring a PV system even with batteries and comms to energy meters is no more complicated than navigating a modern cars menus. In fact using Solaredges setapp tool is easier and more intuitive than resetting the tyre pressure monitoring on my wife's Jazz! I've no experience with anything other than Solaredge kit and that works off the shelf, in my experience. A breeze to install and straight forward to configure. I'm sure theres plenty of other systems that are equally straight forward

I'd be surprised if a PV system is beyond your ability to understand, its more likely that your interests lie elsewhere. If I remember correctly you had a thread about insulating a large car workshop where you discussed roof construction in quite an informed way so you wont have any problem with the mounting and mech installation of PV panels. PV panels produce DC power in the same way a battery provides DC power for a car which Im sure you understand. Connect batteries together as on many wagons and you increase voltage to 24volts....PV panels are the same. If you want to run 240v equipment off a battery in a car/camper/caravan youll pop an inverter in a cupboard. That's the same function as a PV inverter. Much of the functionality of a PV system uses quite simple principles well within the grasp of an awful lot of people......if they want to understand it.