Australia - 3 Phase + Solar


Could you please confirm the CT’s required for the 3 phase home installation in Australia?

The system already has SolarAnalytics wired in and its own CT clamps installed, however this only gives 2 free CT after it’s wired into the mains and solar :disappointed:. Given this, I’m looking at the IoTaWatt to run in parallel, so I can monitor ALL the mains/solar/air-con/household circuits, allowing me to see what is being produced / consumed where, and start getting data to plug into emoncms and its battery simluator to see about sizing a battery (& replacing small and old max. 3kVA inverter with larger inverter, so I can add PV panels as only 3kVA currently).

Not sure would larger inverter also mean 3phase to support 8-10kVA of PV panels (assuming its single phase currently, given the single orange switch)?

I know I need 3 x 100A CT for the mains, 6 x 50A for the power/light/stove, just not sure does the 3 phase air-con and the solar supply need 50A or 100A ?

Edit: Forgot to mention, looking to install a shed in future, but not being an electrican, but assume this means another run going to a sub-board on a future shed. At that point, would I be needing to install another v5 base and a bunch of 50A CT, to monitor the “mains” into the sub-board and the however many power/light etc circuits it ends up with?


You should consult your supplier about single vs three-phase. If you are considering a battery backup solution to run the whole house, probably three-phase.

Picture doesn’t hav3 resolution to see breaker capacities, but 100A mains and 50A branch is probably right. You would need three for the AC.

Sorry, hopefully these are OK.

Would you say however, adding a battery would mean 3 x CT would be required in that scenario, meaning this would require a second v5 base unit ?

Given the pictures above, I’m guessing:

  • 3 x 100A CT (3 phase mains)
  • 10 x 50A CT (being 6 for power/light/stove, 1 for solar and 3 for air-con) ?

Batteries are a broad category. There are a lot of different products that work in different ways. But I would think another unit is probable.

That list of CTs looks good.

Your AC will not need 50amp - 20 amp or even 15amp will be fine

Although your breakers are 100a i would question where your cables and system is capable of even handling that - in fact your mains fuses are 80amp (which is standard) which probably means that your cable from the street will be 16mm 3 phase (depending on how long ago it was done you might have 25mm if you are lucky)

You really should get your main breaker on the board changed for a lower rating - the reason being that if it does not trip until 100amps - then you will blow your main fuses - which you can not replace - you have to get your DNSP out to do so - which can take a couple of days - and they are normally pretty exxy to fix if they deem it be your fault - which they will in this case.

Your board is going to tight for space when you get the IOTAWATT in there and all the new CTs installed

You do not say where you are in OZ ? You would have to check with your DNSP as to what the max single phase inverter size they allow is - many of them limit them to 5KW - but you can purchase up to 10Kw single phase inverters - if you can afford it i would definitely go for a 3 phase inverter for better balancing across the phases and less chance of being throttled by your DNSP

If you are seriously considering a battery - then most of the economical ones are single phase - or you can go a hybrid 3 phase inverter.

If you are wanting to investigate that further - head over to the energy forum on Whirlpool


Craig, are you ‘curto’ on Whirlpool ? I’m the same handle on their.
If you are, be interested in chatting re your setup.
BTW I’m in Goulburn (so just south of you).

Yep - i am Curto on Whirlpool.

Happy to chat - whim me on whirlpool and i will send you my details