Conversion to 3-Phase Power (from Single Phase)

Hey folks!

I am looking at wanting to upgrade my household switchboard to a 3-phase power supply from a single phase. Reason: fast charging of EV at home (in the future).

• Location: Melbourne
• Grid: United Energy (UE)
• Meter Type: Smart Meter

I have initially reached out to United Energy Connections department for their advice regarding suitability for the conversion to 3PH.
They have responded with a very confusing email asking

Kindly ensure that before you request for the job, the 3PH supply should be available in your area.

That was essentially what I was trying to find out before I would engage a REC via hipages.

My question is: for those of you who have gone through the process of upgrading to a 3PH power system, could you please share your experience regarding how you went about getting the job done?

Were there any hurdles that you faced, and any gotchas to be aware of?
Approximate cost of upgrade (ballpark figure)?

Also to be noted, the solar system that I am planning to install will be using high efficiency LG panels with Enphase micro inverters, which I believe will only export power on a single phase, i.e. there will be no 3PH string inverter involved. Furthermore, from what I have read on SolarQuotes, current battery tech can't achieve "Apocalypse Proof Battery Backup" with a 3PH string inverter.

Comments

  •  

    After reading this old article by Finn Peacock (of SolarQuotes), I am beginning to have doubts about 3PH + solar system.
    https://reneweconomy.com.au/3-phase-trickery-utilities-rippi...

  •  

    I have 3 phase power and a 3 phase inverter and 0 problems. Generating much more than we consume at the moment. Planning to get an electric car when the prices are more reasonable. New house though, not upgraded.

  •  

    Could I please ask what's the consequence of having 3PH power system?

    Would it change your billing? (ie: instead of single rates, demand driven, REC charges, etc are separately billed) or subject to different regulations?

    •  

      what's the consequence of having 3PH power

      In what respect? Yes, it impacts how you would go about your installing your solar system, battery backup, etc.

      Would it change your billing?

      No. Only if your tariff code changes.

      •  

        "No. Only if your tariff code changes."

        Aahhh… this is what I am afraid of.

        When I moved to Solar, Ausnet forced me to move into ToU.

        So if your tariff code changes again if you go to 3PH, is it going to be much more expensive?

        Btw I have 4.5Kwh LG Mono X Neon systems + APS Microinverters. Looking to expand that soon so I will be interested to hear your experience with Enphase systems (as I cannot extend my existing one so I need to have secondary set of panels with Enphase as opposed to extending the current APS one).

        •  

          When I moved to Solar, Ausnet forced me to move into ToU.

          You shouldn't have given into such bullying tactics.

          https://www.solarquotes.com.au/blog/time-of-use-tariffs-sola...

          So if your tariff code changes again if you go to 3PH

          No, it shouldn't. I don't see how the two are related at all.

        •  

          Btw I have 4.5Kwh LG Mono X Neon systems + APS Microinverters. Looking to expand that soon so I will be interested to hear your experience with Enphase systems (as I cannot extend my existing one so I need to have secondary set of panels with Enphase as opposed to extending the current APS one).

          I am assuming you are on a property with single phase power supply as well.

          Have you discussed the export limit (DNSP limit) with your installer first?
          https://support.solarquotes.com.au/hc/en-us/articles/1150016...

  •  

    There's no point in trying to 'recreate' three phases from a single phase if your input supply isn't increased, which is the whole point of the exercise here. Especially if you're not running anything else 3-phase like an aircon or industrial motors.

    There's no reason to have a 3-phase charger if a single phase, high current charger will do the same job (which it will). Then you avoid potential issues with solar, batteries etc

    •  

      anything else 3-phase like an aircon or industrial motors.

      I have got a 7.1kW C / 8.0kW H LG inverter in the living room (on a dedicated circuit).
      Another 5kW inverter upstairs. 2 more yet to be installed.

      Then you avoid potential issues with solar, batteries etc

      Agreed.

  • +2 votes

    I am an electrician. You will find most areas will have 3 phase in the street. If you have an overhead connection you will need to have an electrician change your mains box from single phase to 3 phase, change the cabling between the mains box and switchboard. You may have an old switchboard with Asbestos lining/panel - this would need replacing. If you have a modern switchboard - you may be lucky and be able to add a smart meter that can handle 3 phase and therefore not need to increase the size of your switchboard - worst case you will need to increase your switchboard size to accomodate additional meters and isolation links. Then it would be handy to have space for a 3 phase circuit breaker for your EV charger outlet. ** If you have underground power your electrician will need to dig up between house and connection point to replace your mains cable.

    •  

      If you have underground power your electrician will need to dig up between house and connection point to replace your mains cable.

      That sounds really costly and my wallet with be screaming if I do this :D
      I assume it is not doable in a townhouse complex as well?

      • +1 vote

        unless your townhouse complex is very small, it probably has 3 phases available (with approximately the same number of units wired up to each individual phase)

    •  

      If you have an overhead connection

      It doesn't look like I have an overhead connection. There an grey junction box on the side garden (next to my driveway) with a Victorian power industry padlock. So, the cabling must be underground.

      If you have a modern switchboard - you may be lucky and be able to add a smart meter

      I have had a smart meter well before I moved into the property. There is plenty of space on the switchboard itself.

      If you have underground power your electrician will need to dig up between house and connection point to replace your mains cable.

      This sounds very expensive. Just out of curiosity, what would be the ballpark figure for such a project?

  •  

    Reason: fast charging of EV at home (in the future).

    But do you need it? You have all the time when at home to charge. So if it takes 4 hours instead of 2, will it matter? Rarely the car will arrive home dead flat and then need to be charged quickly for a instant turn around?

    Also have a look at the onboard AC charger the car comes with. For example a model 3 can only do up to 11kw charging.

    https://www.tesla.com/en_AU/support/home-charging-installati...

    So a 32amp single phase charger is will give you around ~7.4kw charging. Which is ~3.6kw below the cars max.

    https://www.tesla.com/en_AU/support/home-charging-installati...

    Also to be noted, the solar system that I am planning to install will be using high efficiency LG panels with Enphase micro inverters, which I believe will only export power on a single phase

    Nope enphase is 3 phase friendly. You'll end up with enphase system on each phase using a 3 phase relay instead of a single phase one to bring them together.

    https://www.solarbatteriesonline.com.au/product/enphase-q-re...

    •  

      But do you need it?

      I guess it falls in the category of "nice to have".

      For example a model 3 can only do up to 11kw charging.

      I have found the following webpage recently which provides a more in-depth comparison
      https://thedriven.io/2019/08/18/is-a-3-phase-electric-vehicl...

      So, the gains are marginal. I would save about 3 - 4 hours using a 3-PH Level 2 EVSE.

      Nope enphase is 3 phase friendly.

      Thanks for the heads up.

      I looked into this aspect further.

      https://support.solarquotes.com.au/hc/en-us/articles/1150016...

      So, according to Finn there is a limit to how many panels / micro inverters that can be placed on a single phase. This is set by the distributor - DNSP limit.
      To get around this limit, there are two options:

      (1) 3-PH power supply (using the 3-PH relay you have linked above).

      OR

      (2) Increase panel efficiency

      Obviously, option (1) is a bit more flexible than option (2).

      •  

        I have found the following webpage recently which provides a more in-depth comparison

        Its pretty old and has some glaring errors like

        So, the gains are marginal. I would save about 3 - 4 hours using a 3-PH Level 2 EVSE.

        from dead flat…… Most people in day to day use, rarely come home dead flat.

        The base model 3 has a 55kw battery and can do 400+km on a charge, so even at 7kw its under 8 hours from DEAD FLAT. But you rarely come home dead flat and you rarely go above 80% for charging day to day usage. So that leaves around 33kw of battery you might normally use, which is under 5 hours to charge.

        So, according to Finn there is a limit to how many panels / micro inverters that can be placed on a single phase. This is set by the distributor - DNSP limit.

        These are network distributor rules and applies to everyone regardless of the solar system brand, you claim was enphase will only work on a single phase. Which is wrong.

        Obviously, option (1) is a bit more flexible than option (2).

        If you can get 3 phase cheaply then get it for sure. But spending $5k for example to get 3 phase just so you can export more, might not be worth it in the long run.

        Export rates are dropping all the time. Vic is now 7-8c/kw for solar export. Hardly worth bothering about.

        •  

          Most people in day to day use, rarely come home dead flat.

          No one is disputing this.

          Its pretty old and has some glaring errors like

          Not seeing the glaring errors in the thedriven.io article.
          Are any of the full charging figures incorrect in Table 1?

          you claim was enphase will only work on a single phase.

          I admitted I was wrong already in my first reply, and thanked you for the correction.

          But spending $5k for example to get 3 phase just so you can export more

          Yes. No way in hell would I spend that much for 3-PH.
          I would rather that money go towards a decent solar system and/or battery backup solution.

    •  

      https://www.solarbatteriesonline.com.au/

      Also, have you used this company, and/or recommend them?

  •  

    I would think that either United Energy didn't understand the request or you asked the wrong question.

    I'd allow $4k-$6k to string the new wiring from the nearest pole, reconfigure the distribution board to take advantage of the 3 phases and the supplier fee. Unless your house is relatively new then count on some other electrical work being needed.

    I'd question whether you need 3 phase. My neighbour just plugs his Tesla in to a 32amp circuit overnight. I have 2 other mates with Teslas and they don't run 3 phase either.

    Have you actually got a quote from a Level 2 sparky and then done the sums to determine the payback period?

    •  

      I'd question whether you need 3 phase. My neighbour just plugs his Tesla in to a 32amp circuit overnight. I have 2 other mates with Teslas and they don't run 3 phase either.

      Agreed, as I said above, the onboard charger for a Model 3 is 11kw, a 32amp single phase circuit will give 7.4kw. You're really only going to be getting a 'extra' 3.6kw out of 3 phase, that comes with a lot of cost.

      Plus when charging at 'home', time is rarely an issue. A car even from near empty will recharge 'overnight' and be ready with a full battery by morning.

      So not really sure why the OP as such a need for rapid charging.

    •  

      I would think that either United Energy didn't understand the request or you asked the wrong question.

      It was a simple enquiry regarding the suitability of 3PH for my property before hiring a REC.

      But that's moot now. The costs simply outweigh any potential gains.

      Have you actually got a quote from a Level 2 sparky

      Will be doing so when I purchase an EV.