In Blog, Inverters, Micro Inverters & Optimisers

Can I Install a 10kW Solar System on Single Phase? – The 2023 Gen24 Update!

fronius primo image
Fronius Primo Gen24

The maximum residential solar system size allowed here in Brisbane used to be 5kW of inverter capacity per phase. Since the majority of households are single or three phase, that meant the largest you could install was 5kW solar systems, and 15kW solar systems respectively. It does appear single phase households get the short straw, as currently due to high feed-in tariffs and the reducing cost of solar, larger solar systems actually save you more money in both the short and long term. However, the rules have changed. Now, according to Energex, we can install a 10kW solar system on a single phase premises:

5.4 Inverter Phase Limits: Single phase inverters, are acceptable up to and including 10kVA of installed capacity on a customer’s installation, however total export shall be limited to 5kVA or less via partial or minimal export operation, as per Section 5.9.1. Proponents with a single phase service wishing to export greater than 5kVA will need to make application with their retailer to upgrade their service to two or three phases.

So, post over. You can install a 10kW solar system on single phase, and this should now be the norm for single phase, right?

Well, not exactly. The line, “Export Shall be limited to 5kVA or less,” is worth understanding to see if a large system is right for you. 

What is “Export Limiting?”

The concept is simple. Energex will approve your solar connection, as long as you ensure no more than a set amount of power is sent back to the grid at any one time. Before these connection standard changes, if you wanted an inverter larger than 5kW, you needed to upgrade to 3 phase. This can be quite an expensive upgrade and could be comprised of trenching, traffic control, Energex fees, electrician fees, etc. In some circumstances, it just isn’t financially viable. You were better off installing a 5kW solar system, just having it cover what it could. So now, for high usage single-phase households, there is an alternative option – keeping your connection as single-phase, but installing up to a 10kW solar system with export limitation. The far more financially viable option. If you read into Mark’s previous blog that debunked Goldilocks solar and showed the benefits of going as big as possible, you may also be thinking 10kW inverter capacity should be the norm for a single phase. However, because we’re required to export limit the site, we have to ensure the household benefits from it.

How Does it Look?

I always like a visual explanation, and I will find any excuse to post an image of a graph. Below is the solar production of a household limited to 5kW exportation, with a Fronius 8.2kW inverter and 10.2kW worth of panels. The green filled-in portion is what is being sent back to the grid, while the grey filled-in section is what’s being consumed by the household. In this export limited scenario, the green portion can never exceed 5kW.

10kW solar system restricted to 5kW export

As you can see I’ve also filled in the potential missed production in a darker green colour. This is an estimate as to what the system could have produced, and therefore sent back to the grid, but was unable to do so due to the 5kW exportation limit.

However, if the base load was increased, the system would be able to reach its full potential, and nothing would be “wasted.” Below is an example of what the production graph might look like with a higher base load.

10kW solar system export limited

You can see that by increasing the base load of the house, there is no “wasted” production as export limitation doesn’t need to occur. This is good practice for installing a larger than 5kW solar system on single phase.

New Fronius Gen24 Battery Ready Inverters – 2023 Update

gen24 electronics chassis review 2
Fronius Gen24

As of this year, Fronius have improved their Gen24 range from 5kW and 6kW sizes, to the meaty 8kW and 10kW sizes. Previously, if you wanted to capitalise on these larger export limited systems, you’d have to forgo the new Gen24 Inverter and install the oldschool 8.2kW Primo instead. Or, the maximum sizing you could install would be 6kW – not that impressive these days. With the launch of the 8 and 10kW Gen24 Inverters, you can get an extremely large single phase sizing, while also being prepared for DC ready batteries. This is a massive development for Fronius, and a really good solution for all single phase households. We are seeing a high demand for the 8kW unit in particular, as the capacity it allows means the required panels fit on most roofs without breaking the bank. Or you could just go all out and go for a 10kW Gen24 connected with 13.2kW of panels – a truly impressive sizing previously reserved for three phase households. This sizing would potentially have a large amount of export limiting, so it’s important you have a way to really use that power in the day time so as it’s not wasted.

Have I missed the boat if I already have a 5kW Solar System Installed?

If you already have an existing solar system in place, and more roof space available, we can simply install an additional Fronius Inverter alongside it. As long as the new total inverter capacity does not exceed 10kW, it also doesn’t matter what type of inverter you currently have. However, we would need to install a Fronius Smart Meter to control the Export Limitation, and the consumption data would unfortunately not report properly. But, if your existing inverter is a Fronius Primo, we can simply link both data loggers, enabling you to also have full consumption data of both inverters on the one monitoring portal. You can also utilise your existing smart meter if you had one on your original install.

So, if you’re finding you have large daytime usage and more roof space to play with, it may be worth giving us a call to discuss your options to see if and how you can achieve a 10kW solar system. With the launch of the new battery ready Gen24 ranges, it’s actually a very good time to get a 2 for 1 on your system upgrade. A new system would allow for a larger capacity and therefore larger savings, but it would also now be battery ready.

10kW Solar System Size Restrictions with Batteries

Tesla Powerwall

If you wanted to install larger than 5kW of inverter capacity on single phase to help cover your high base load, you could not install a Tesla Powerwall or any other AC battery that pushes your total inverter capacity above 10kW without entering a dynamic export agreement. This is a topic in of itself, but essentially instead of a 5kW export limit, Energex will allow a range of 1.5kW to 10kW export as they deem fit. . Since the Powerwalls’ AC to DC inverter has a 5kW output, anything larger than a 5kW Solar inverter pushes us above the 10kW Energex limitation. You could install DC batteries just fine, and this is why a Fronius Gen24 expansion may be the better option. Furthermore, if you require a system larger than 5kW to meet your household requirements, you’re not going to find enough excess generation to charge an AC battery anyway, so the point is somewhat moot.

Reviving the Fronius Relay

fronius relay hot water timer solar

If you want to take advantage of a bigger system on single phase, but don’t have the base load to justify it, and have an off-peak electric hot water system, then it’s a good case to revive my previously declared dead, Fronius Relay. The general concept of the post was; exporting power is a more valuable solution than heating a hot water unit, due to increased feed-in tariffs. But since the anticipated base load is not high enough, you may run into this “wasted” generation. This means the production diverted to the hot water unit via the use of a Fronius relay would have been unable to be exported anyway, so the calculation changes. This is a prime revival case for the Fronius hot water relay, but as the discussion is a bit more in-depth it’s best to read the blog first to understand it better.


Through the use of export limiting, single-phase households can now install a 10kW solar system. However, it’s important to understand the effects of export limitation, and whether it’s a good solution for your particular circumstances. Having additional intelligently timed loads, or excessive daytime usage will minimise, or even eliminate the “wasted” power export limitation incurs. If you have an electric hot water system, it’s also a good revival case for the Fronius Hot Water Relay. If done correctly, larger single-phase systems through the use of Export Limitation can be a great, cost-effective alternative compared to upgrading to three-phase.

As of 2023, you now have the option of true battery ready Fronius Gen24 Inverters, in sizes that really capitilise on a large single phase export limited system. You can either expand your existing system with our 5 or 6kW units, or if you’re installing solar for the first time, go all out with a new 8kW or 10kW Gen24 Inverter and a system size to suit. As always, we’re always happy to have a chat to go through the options.

ben neville
ben neville

Ben Neville

Sales Designer/Estimator

MC Electrical


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43 Comments on Can I Install a 10kW Solar System on a Single Phase?

Eric McInnes said : Guest Report 2 years ago

Gday... Good information on your website on 10kW systems (2 x 5kW). Thx for that. Im based in WA and wnat to go 100% solar and battery on my farm house up the north coast from Perth. Already have a 5.2kW solar panels and Fronier Inverter. So thanks again and that has given some food for thought. The Fronier Filter is what I would need if I decide to keep the mains power connected... Regards

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Mark C said : administrator Report 2 years ago

Hi Alex, there is now a solution without a battery! I call it Batteryless backup. Check out my Fronius Gen24 review

Alex M said : Guest Report 2 years ago

Hi Mark, Love the blog. We have a 11kw solar array and a 10kw 3-phase inverter. It is not uncommon for us to have black outs but our 3-phase inverter needs grid power to work. What is the best solution for us to be able to utilise the solar during a grid outage? Would it be possible to install a 5kw single phase inverter to the existing solar with a manual change over switch to use during outages? Any help would be great. Cheers, Alex

Elliot said : Guest Report 2 years ago

Hi Greg. It might be worth reading our oversizing blog. The CEC limits inverter oversizing to 1.33 or 33% oversizing, this means a 5kW inverter can only have 6.6kW of panels on it.

Elliot said : Guest Report 2 years ago

Hi Mel. That does sound a bit strange. I would recommend contacting your installer and organising for them to take a look. They may be able to figure out the problem by just looking at your monitoring.

Greg said : Guest Report 2 years ago

Hi Mark What a great article. You may be able to help me with the following. Would it be OK to have just one 5kW inverter with the 10kW panels or would it be a waste of money? Therefore better off with the 8.2kW???? Thanks Greg

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Mel said : Guest Report 3 years ago

Hi Mark, I have 10 kw panels and an 8kw inverter. Before they changed my meter I was generating 58kwh per day and around 7.6 kwh at peak and 6.5 at 8 am. After they changed the meter, it is still doing 6.5 at 8 am but at peak it is only producing 3.5. is this because the meter is limiting the amount of kwh that is produced? I'm worried there is something wrong with my system.

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Mark C said : administrator Report 3 years ago

Hi Yan, In Australia, you can only install up to 6.66kW on a 5kW inverter if you want to claim the "rebate" (STC's). However, there is a loophole... If you have a battery installed you can oversize the 5kW inverter to the maximum capacity of the inverter. This is really dependant on voltage and the current of the panels, but in general, I wouldn't recommend installing that much.

Yan Ma said : Guest Report 3 years ago

can I install 8.2kw panel with 5kw invert

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Mark C said : administrator Report 4 years ago

Hi Trevor. It's about net metering. The electrons don't jump phases but the meter records the total import and export and charges or credits you on the net instantaneous surplus. See this blog:

Trevor Hudson said : Guest Report 4 years ago

If i instal a thtree phase inverter. How is the solar generated power distributed to my 3 phase supply lines i would be reluctent to send my generated power back to the grid and buy back at a higher price. Could the inverter supply the individual phases according to demand. Example if my load on phase A was 6kw and phase B was next to zero. My panels are producing 6+ kw would Phase A get that supply or only one third of the panel output Cheers Trevor

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Ben Neville said : administrator Report 4 years ago

Hi Terry, Sorry for the late reply. I can confirm this will work, but just make sure you are being export limited by consumption data, and it's not simply one inverter limited to 5kW.

Terry said : Guest Report 4 years ago

Hello, I found the information very useful and informative regarding installing 10KW solar system. I recently received an offer from my local installer suggesting that 10KW system with two 5 KW panel systems with two 4 KW inverters is suitable for my house with one phrase, which uses electricity only instead of 10KW with 8KW inverter which is more expensive according to a quote. Therefore, I just wanted to know if it is ok to install two inverters which separately connects to 5KW panels each. It would be highly appreciated if you can give your opinion in this matter at your earliest convenience. Thank you very much in advance. Kind regards, Terry.

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Ben Neville said : administrator Report 4 years ago

Hi Chris, Apologies for the delay in a reply. Sounds like an incorrect configuration, I'd get the company back out to fix the issue. The system should be able to generate 10kW at a 5kW export limitation if the export limiting is set correctly. They might have set total generation to 5kW instead of setting total exportation to 5kW. Otherwise you've basically got 5kW worth of solar doing nothing. Alternatively some earlier dodgy methods of handling export limitation was to set the 2nd inverter to 0kW exportation, but that would still enable you to produce more than 5kW at one time. It doesn't sound like that's what's going on here, it sounds worse.

Ben Neville said : administrator Report 4 years ago

Hi Maryanne, Apologies for the long delay on this one. If your paperwork stated you were getting a 10kW inverter, that's definitely what you should be getting. If they downgraded you to an 8kW inverter, I would be demanding compensation regardless of what they can and can't handle.

maryanne eldridge said : Guest Report 4 years ago

Hi i just had a question in regards to getting a 10.5 kw solar panel system installed with a 8kw single phase inverter, would this system work more efficiently with a 10kw inverter? My paper work stated that I was getting a 10kw inverter but after installation I only received a 8kw, I have complained to the company but they have told me it was a "mistake" and that most installers will only install an 8kw system as they can run up to 33% more. Is this true? Am I being ripped off or does it not make any difference?

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Chris Dippenaar said : Guest Report 4 years ago

Hi Mark, great article and very relevant to me. I have 40 x 330W Seraphim blade cells and two 5Kw Growatt inverters installed. There is also an Eastron smart meter installed to manage the two inverters. The problem I have is that the smart meter is limiting the output of the second inverter to a maximum generation of 5Kw for the whole system, irrespective of how much electricity is consumed in the house. It isn't therefore limiting only the export to 5kw, it is limiting the generation to 5Kw. Is this the way it is supposed to work or is the system configured wrong?

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Mark C said : administrator Report 4 years ago

Hi Randihir, It depends where you are, but yes you can in qld. You would have to "export limit" to 5kW.

Randhir said : Guest Report 4 years ago

I have a Three kw system installed.Can I add another 7,kw

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Mark C said : administrator Report 4 years ago

Hi Frank, if it actually NE and NW (or close) then yes I would split them. Generally, I don't agree with facing them in the direction to suit usage, but face them all north if possible. Here is why:

Mark C said : administrator Report 4 years ago

Hi Mike, it depends on which electricity distributor you have. In Qld, you don't really have a decent option, except a small AC coupled Enphase battery - because the total you can have is 10kW (including the size of the battery). Otherwise, you need to DC couple a battery, and you would probably need to swap out your inverter with a hybrid inverter.

Mike said : Guest Report 4 years ago

I have a 10kw grid tied system with an 8.2 Fronius Primo inverter on a single phase. I have been looking at adding battery storage but do not want to go down the 3 phase path. Can you recommend a set up that achieves this.

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Frank Perry said : Guest Report 4 years ago

Hi , I am considering a rooftop solar system, a rep from 3 solar quotes has said I can fit 6.6kw system on one side of my roof, with all panels facing N.E. My feed in tariff would be about 7c to 8c/kwh, so I am more interested in using / storage rather than exporting. Would I be better off having around 50% of panels facing S.E. 50% facing N.W as thats the lie of the gable roof, to enable me to use solar for the air cons etc for the most time, my average daily consumption is round 13kwh

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Mark C said : administrator Report 5 years ago

Hi Trent, If you have a high daytime baseload, installing a larger system than 5kW could be a good idea. It depends on your local network, so you are best to contact someone local for a quote. Try getting quotes from

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Trent said : Guest Report 5 years ago

Hi, I found your info usefull for my needs. I currently have single phase power and run a pool on the off peak metre (controlled load) and a hot water system. We just got ducted air con installed and it has pushed our bill through the roof in winter. Currently in winter using 48kw per day. What do you suggest the most ideal set up and size would be for my place. Thankyou kindly Trent.

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Ben Neville said : administrator Report 5 years ago

Hi Amanda, It depends on the inverters utilised and your grid restrictions, but yes, you most likely could have had 2 x 5kW Inverters (one on each phase) with the full 10kW maximum exportation. Perhaps there was a reason this was done via an export limited scenario?

Amanda Ardern said : Guest Report 5 years ago

We just had a system installed with 7.8kw panels and a 6kw inverter. We are obviously limited to 5kw export. But we have two phase to our house, does that mean we could have actually set up a system to export a maximum of 10kw?

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Ben Neville said : administrator Report 5 years ago

Hi David, Two phase is quite rare, and I'm not sure on your exact DNSP guidelines. Best bet would be installing 10kW of inverter capacity, 5kW on each phase, without any export limitation set. As you are installing multiple single phase inverters across multiple phases, the Inverters would need to be interlocked with the ability to shut down simultaneously. You technically could install more inverter capacity on each phase, but both inverters would need to be export limited to 5kW on each phase, requiring two consumption meters. This is expensive, and probably not required as 10kW capacity should be enough.

David Brown said : Guest Report 5 years ago

Hi Ben, i live in NSW on 5 acres and have 2 lines (2 phase) coming in so how much can i export into the grid?

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Ben Neville said : administrator Report 5 years ago

Hi Matt, Are you noticing your Solarweb production data "clipping." In that your system could be producing far more at times but is being limited to the 5kW exportation limit? If not (and you only used 9kW) your export limiting could be not set correctly. But if so, then yes, you are a prime candidate for a hot water relay assuming you get a large hot water cylinder that can go through the night without requiring heating.

Matt B said : Guest Report 5 years ago

I've just had a 7.8kw system installed in Melbourne. We're on single phase and thus export limited to 5kw. I'm a perfect example of the "oversized system with low base load". Yesterday I exported 52kwh to the grid, yet used only 9kwh. We currently have a 15 year old gas storage hot water unit. Am I right in thinking that we'd be great canditates for electric hot water with the Fronius relay? Thanks for the info.

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Paul said : Guest Report 5 years ago

Thanks Ben for responding, and for mentioning the Solarwatt battery (I have actually looked in to them) interesting idea & concept. The one thing I didn't mention previously was - I really want to have backup power during a power outage (even though outages don't happen very often where I am). I will definitely keep my fingers crossed that something changes regulation wise (or a new product appears) by the time battery storage becomes financially viable (which might not be that long if the Victorian Battery rebate happens after the next state election in November). Will be interesting to see if Michael (Post Code: 3777) has any luck getting his 10kW Solaredge inverter and Tesla battery system approved. Alternately I will just have to bite the bullet and replace my inverter (luckily I don't have more than 6.6kW of panels currently). Thanks again for mentioning/explaining the 10kW inverter limit in your great article (I will now be able to ensure that I take this into account when answering any general questions about solar & battery storage from friends and family).

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Ben Neville said : administrator Report 5 years ago

Hi Paul, Thanks for the feedback! Hopefully the regulations regarding AC batteries change by the time they become financially viable. There is also the alternative option of a Solarwatt battery which won't contribute to your total inverter capacity.

Eliana parker said : Guest Report 5 years ago

Thanks for this valuable information about the Capacity of single Phase. Very informative Blog. This Blog will very helpful in Solar panel system .

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Paul said : Guest Report 5 years ago

Good article, oh snap! I didn't realise the 10kW inverter limit includes the battery inverter, Doh! That's going to put a rather large spanner in my plans for a battery with a 5kWh inverter in it, since I currently have a 6kW string inverter. :(

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Ben Neville said : administrator Report 5 years ago

Hi James, Your roof layout is going to dictate how beneficial a bigger inverter will be. If you have a full north facing array, a 6kW Primo might be the go - assuming you are already proceeding with a Fronius Smart Meter and you use some power in the day so as not to "waste" the additional 1.6kW. However if you have a mix of East and West, your array may not be able to produce more than 5kW for the majority of the year anyway, so a 5kW Inverter will be suitable.

James S said : Guest Report 5 years ago

I am about a month out from getting a 6.6 kW system installed with a Fronius Primo I.V inverter, would i be better of getting an upgrade to a bigger inverter to take advantage of that extra 1.6kW of panels? Or is it not really worth it for a small electricity user?

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Ben Neville said : administrator Report 5 years ago

Hi Tim, Unfortunately I'm not across the SA power network regulations, but from reading some other sources that do have a more SA focus, I don't see why not. I believe a timer/relay linked with a hot water unit, especially an element with a smaller kWh draw, would get the most out of an export limited system. An AC battery adds to our total inverter capacity here in Brisbane, and would therefore not be approved. However, if it were possible in SA, a battery would be the best contributor to a higher base load. It also makes their return a lot better as we'd be unable to export the excess anyway, so Feed In Tariff calculations are removed from the equation. Meaning, their prices may not even need to drop "significantly." just enough to make the math work.

Ben Neville said : administrator Report 5 years ago

HI Mark, Thanks for the feedback. Unfortunately there is no way to "unlock" the inverter to snag any potential missed production. You would need to either install an additional inverter like you say, or replace your 5kW Fronius Primo with a 6kW or 8.2kW Fronius Primo, with export limitation enabled.

Ben Neville said : administrator Report 5 years ago

Hi Michael, Thanks for picking that up, although like you say luckily it's still relevant - 10kW of inverter capacity, 13kW of array. Great to hear you can achieve 10kW of inverter + the Tesla Powerwall, that's something we can't get approved for here - yet.

Michael Nardella said : Guest Report 5 years ago

Your email has 13kW in the title, although I presume the article is still relevant. Similar regulations apply here and I have applied for approval for a 13kW single phase system with 5 kW export limiting using a Solaredge 10kW inverter. I already have a Tesla battery installed.

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Tim Chirgwin said : Guest Report 5 years ago

Hi Ben, a great workaround, would this comply on SA Power Networks SWER line? While mark explained in a previous blog that timers for hot water are not a good option, does the balance swing if a timer and lower wattage HW element be fittet, to give a long baseload for an oversized system such as 13kw panels on 2x5kw inverters. Further, if battery storage cost drop sufficiently, would this work on a system where part of the house is connected via the second inverter in a UPS scenario, at least for lower amp circuits?

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Mark B. said : Guest Report 5 years ago

Great article Ben and very interesting. So with my current 5kw Fronius plus smart meter together with 6.6kw of panels is there a way to unlock the Fronius to use the full 6.6kw without installing another invertor ? My smart meter relay runs my electric hot water during the day. Thanks.

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