Is this 2 phase power? Any decent 2 phase hot water systems?

Discussion in 'Electronics & Electrics' started by -Sk3tChY-, Oct 12, 2018 at 11:56 PM.

  1. -Sk3tChY-

    -Sk3tChY- Member

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    Currently have a large 315L hot water tank in a really inconvenient location at my house.

    I've been forced to do some renovation/repair work and am wondering/hoping I'd be able to remove the big tank and replace it with an electric instantaneous system.

    Took a look at my power box and from what I gather the three black things (fuses I've been told) with the yellow zip ties are my mains coming in. Of which, it seems there are 2 active and 1 neutral? (2 phase power)

    Here's a few pics:

    [​IMG] [​IMG]
    [​IMG] [​IMG]

    From what I gather, if I had triple phase power I'd expect to see 4 of those black things with zip ties - 3 actives, 1 neutral.

    The house does also have a fairly large ducted air con system, which I thought would have required 3-phase power. Here's specs of the outdoor unit:

    [​IMG]

    I obviously don't plan on doing any type of electrical work, at this stage I'm just wanting to try and identify my options.

    If I only have 2 phase power:

    1. Do 2 phase electric instantaneous hot water systems exist? Are they any good?
    2. Is it expensive bringing in a third phase? Does it take a long time to arrange?

    Any help much appreciated. :)
     
    Last edited: Oct 12, 2018 at 11:59 PM
  2. DarkYendor

    DarkYendor Member

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    I think that’s just old 3-phase. The Neutral is bonded to earth via the MEN link, so it’s not protected by a fuse. (Modern systems would have a 3P+N breaker protecting the Neutral as well).

    That AC is 3-phase plus Neutral based on the photo (3N~).

    I’ve never seen two-phase equipment, but it probably exists. But I don’t think it’ll be an issue. Obviously get an electrician to confirm, but I’m pretty sure you have a 3-phase connection (and with higher current than the normal 3x32A they install these days).
     
  3. OP
    OP
    -Sk3tChY-

    -Sk3tChY- Member

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    Much of what you've said is beyond me, but I'm very happy to hear I likely have three phase power! I'll take a few more photos tomorrow and upload them, hopefully someone else here will be able to confirm.

    Here's another old pic I managed to dig up, not sure if it will be of much help:

    [​IMG]

    Presumably if the AC is 3-phase and has been operating fine at least the 7+ years since I bought the property - I've got 3-phase power. Does that mean the AC unit should have 3 active wires going to it?

    Just hoping someone here will be able to confirm, so I can start researching electric instantaneous hot water systems and see if they're any good. It would be great being able to remove the huge 315L tank!
     
    Last edited: Oct 13, 2018 at 1:25 AM
  4. Privatteer

    Privatteer Member

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    Yes. From the pictures provided you have 3 phase power.
    The aircon is on a 3 phase 20 amp circuit.

    However just from those pictures I can see some issues that should be addressed by an sparky.
    It appears you have a 63amp supply judging from the marking below fuse. Yet what seems to be the main switch is under-rated at 30Amps.
    I would not consider the earthing terminations (green wires) to comply with the requirements.
    If I am not mistaken black wires have been used on the active supply to some circuits something I highly doubt any sparky has done.

    If I am reading the faded label correctly there is another sub-board somewhere fed from the main one?
    To fit another 3 phase circuit you are going to have to re-configure the board pictured. Doing so will trigger the requirements to bring it up to the latest standard in regards to RCD protection.
     
  5. OP
    OP
    -Sk3tChY-

    -Sk3tChY- Member

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    Thanks mate, appreciate the confirmation.

    I'm not surprised the board isn't up to standard, the previous owner did a lot of questionable work on the house; hence the reason "I've been forced to do some renovation/repair work".

    I take it you're referring to the big white switch located in the bottom left hand corner of my photos? (Below/outside the main board/box) Presumably, this just needs to be replaced with a XXamp switch?

    Considering I only see green wires in the photo showing behind the panel, I'm guessing this is because he has just duct taped or used connectors? What would the resolution to this be?

    A lot of things that were done at this house are questionable, so no doubt there's been the odd rogue that's gone in on this box. Hoping those black wires, could just be swapped for appropriately sized red wires?

    You are correct, there is a sub-board in the garage; which at least appears to work as it should - i.e. Power works in the garage.

    Would you have any rough idea on how much it would cost to get something like this done?

    I'm honestly very tempted to spend the money if it means I can get rid of the huge 315L tank. Especially if a good 3-phase electric tankless could supply hot water throughout the house all year round.
     
  6. money_killer

    money_killer Member

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    Get a heat pump HWS they are cheap and efficient to run
     
  7. OP
    OP
    -Sk3tChY-

    -Sk3tChY- Member

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    Here's a bigger picture of everything that's currently contained within the power box:

    [​IMG]

    The thing in the bottom right is a "Ripple Control Receiver" branded with Integral Energy. I'm guessing the other two grey units are something to do with the power company, as they're also zip tied - guessing they're the meters, but not sure why I would have two of them?

    If I were looking to have a sparky connect a 3 phase electric tankless, what would I roughly be looking at in terms of cost/work?


    Looks like these still require large tanks? I'm wanting to get rid of the tank.

    I'm hoping something like this Stiebel Eltron unit (DHE 27 AU) would be sufficient enough to provide good hot water to a shower and tap or two simultaneously.
     
  8. DarkYendor

    DarkYendor Member

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    I think sdding a circuit will require bringing the board up to the current spec, and Bringing that board up to AS3000 will basically mean replacing the entire thing (especially with the new requirement that all circuit must be RCD protected - previously it was only Lights and GPOs). So probably >$1000.

    Is there wiring for the existing heater that is no longer required?
    Is gas an option - I think it's typically 1/4 the price of electricity for heating water.
     
  9. Privatteer

    Privatteer Member

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    Looking at it the storage HWS has been setup for off peak usage. It may also have a bypass/boost element on normal metered usage.

    Cost for the instantaneous could vary greatly. It will depend on the difficulty of installation, location of the unit, its current draw and thus cable size required.

    The main switch needs to be replaced with something rated to switch the supply, ie 63Amp or larger.
    The earthing at a switchboard has to land at a earth bar or on a main earth point in the approved manor, not a dozen different joins.
    While the color coding is simple to fix its a big indicator that someone has been doing unlicensed work without the necessary knowledge. I suspect a onsite look would identify some more issues.

    I don't do domestic but I would be guessing around $800 to sort the mess out. That's allowing for individual RCD protection on each circuit that requires it.
    Even then its going to be a tight squeeze by the time you add a 3phase main switch and the old asbestos panel does not help. Start having to move the meters/fuses and that cost will skyrocket.

    If it was my own place I would be considering if it would be worth pulling some or all of the circuits back to another location ie garage db. Or just feeding the new instantaneous from it.
    The only issue is the current cable to the subboard is only good for 32Amps and may be a limiting factor unless upgraded.
     
    Last edited: Oct 13, 2018 at 11:19 PM
  10. methodMAN

    methodMAN Member

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    Its not 2 phase electric, but single phase with off peak and a boost element for when you use all stored hot water in the tank, it heats up the water on regular rates. Single phase with 2 separate circuits.

    As stated you already have 3 phase.

    mM
     
  11. money_killer

    money_killer Member

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    My understanding for a domestic install the product you want, will just chew the power $$. A gas instantaneous system (they have no storage tank) is what people install. I have never seen a electric instantaneous installed at a home they are common in the commercial office scene. But products and technology change so its worth just double checking on, if you get one installed i would be interested in how it goes and the running costs of it.
     
  12. ArmoureD

    ArmoureD Member

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    Id stay away from the smaller steibel units. They are only good for 1 water outlet/tap.

    The larger unit is fine but requires 40 amp per phase.

    Id stick to the storage solution or get an instantaneous gas unit with bottled gas if mains gas is unavailable in your property.
     
  13. OP
    OP
    -Sk3tChY-

    -Sk3tChY- Member

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    Would it not be possible to simply have someone add the required circuit without re-doing everything? Obviously, fix up a few of the other mentioned issues like larger amp main switch, correcting the cable colours/gauge and the new circuit being added would be RCD, etc.

    Unfortunately gas isn't an option, unless I go with bottles - in which case rather than having a huge 315L tank, I'd have a couple of huge gas bottles. My concern isn't necessarily the efficiency, it's more the fact I currently have this huge 315L tank right by the backdoor, which I'd like to try and get rid of.

    The current HWS is off-peak only, correct.

    The original tank was dual-element and there's 2 actives coming in at the tank. Initially I thought one would be peak and the other off-peak. So you'd wire up the larger bottom element for off-peak and small top element for peak to top-off the tank where necessary; it seems both actives are off-peak though.

    No idea if there's a boost/bypass feature somewhere though, this would be interesting?

    Would meters/fuses and the likes need to be moved? Wouldn't they just remove the switchbox, two main swiches and dodgy looking sensor light switch:

    [​IMG]

    And essentially just integrate all of this into a single switchboard?

    From what I gather, the electric tankless units are actually more efficient than storage tanks. The FAQ for one of the units I'm considering says they're 30% more efficient.

    Obviously, I take all these figures with a grain of salt, but as long as the electric tankless isn't any more expensive than the existing 315L tank, I'd be fine with it. My main goal is getting rid of the big tank.

    At this stage my biggest concern is the water temperature. The electric tankless i'm looking at states 60° which doesn't seem very hot, but I believe this refers to the temperature "rise" - so if the incoming water temperature is 10° and you have it set to 60° the water coming out would be 70°, provided flow isn't too high.

    Would definitely be going for the largest three phase unit I can get. Would you happen to know any other units worth considering? Steibel Eltron seems the only "reputable" type vendor I've come across so far.
     
    Last edited: Oct 14, 2018 at 3:00 PM
  14. ArmoureD

    ArmoureD Member

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    Last edited: Oct 14, 2018 at 9:09 PM
  15. DarkYendor

    DarkYendor Member

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    I think the problem would be that those changes would all require more room, which probably isn't available as it is. And if that panel is asbestos, you may be limited to what you can do without any cutting or drilling.

    EDIT: That said, I'm not an Electrician, so I can't say for sure.
     
  16. ArmoureD

    ArmoureD Member

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    Im no eagle eye but I'm certain your main switch is not 30a as others have stated.
     
  17. rickbishop

    rickbishop Member

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    With that ugliness, I would be getting a whole new switchboard. Here's mine: https://i.imgur.com/ylFJuTq.jpg

    Basically, you've got two meters in there and a ripple receiver that would need to be relocated to a new board. Pretty much everything else I would throw away and start again, as well as separating some circuits and putting them onto their own RCBO (say, your laundry on its own circuit, and if possible, separate the circuits in your kitchen). It looks like you already have 63a 3 phase coming in, so a new 63a 3 phase main switch would be good.

    I would absolutely encourage you to do this, because of a VERY good reason: You will more or less HAVE to do it if you want to put a solar system on the roof. But, the good thing is you can put a VERY large solar system in, because you have 3 phase, potentially up to a 15kw system.

    As for your HWS, pretty much the only way to get rid of the big tank is either get a small electric one which WILL cost you a shitload in running costs, or seriously consider a roof mounted solar HWS which is electric boosted.

    And your main switch definitely is a 32a 3phase.
     
    Last edited: Oct 15, 2018 at 1:17 PM
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  18. ArmoureD

    ArmoureD Member

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    His main switch is NOT 32a. Why do folks keep saying that. Show me where it says 32a
     
  19. TonyR

    TonyR Member

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    Just a random thought...

    Have you considered instantaneous gas hot water. We have 2 of them for 3 bathrooms and 1 kitchen, and they are great.

    Might mean less mucking about with the electrics.
     
    money_killer likes this.
  20. rickbishop

    rickbishop Member

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    For your consideration:

    [​IMG]
     

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