Going to three phase power

Hi, I have a 5.4kW system on my house and wish to put panels on a new garage. I live in the eastern suburbs of Sydney. I am looking at a 4.6kW system for the new garage. I have heard that I will need to upgrade to three phase phase power to balance the street load. But I have also heard that if I go with Enphase micro inverters I do not have to upgrade to three phase. This does not make sense to me, but there may be some underlying reason. Can anyone confirm this ? Also, what is the typical cost for upgrading to three phase ?

It depends on your local network provider (Ausgrid does most of Sydney I think) and what approval you can get for more solar generation. I’m not familiar with Ausgrid so hopefully someone local can explain. Here’s a link to Ausgrid’s application… https://www.ausgrid.com.au/Connections/Get-connected/Apply-for-a-connection

Enphase Micro-inverters are a great option but will not make any difference to how much you get approved or whether you need to upgrade to a 3-phase supply. Micro-inverters can be easily export limited but so can any solar inverter with an additional consumption energy meter.

Other options could be to install battery along with the new solar system and have zero export on the new system. If you have high consumption you may not need a battery all. If the new solar system is mostly for self-use (air-con, pool pumps etc) then maybe get a zero export and save the hassle of upgrading to 3-phase to get more solar.

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Hi Phil,

I think you’ll find the reason you’ll have to go to three phase is because you are only allowed to feed maximum of 5 kW / phase into the grid (in any state in Australia) and as you will have nominally 10 kW capacity you would at least to upgrade to a two phase supply.

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I agree to the suggestion by Svarky and adding 4.6kw with 0 export, only for self-use
you may pm me ( see CEC installer list ) for the 3rd quotes so you can see there are many ways to solve your enquiry
Regards Esmail Attia