Phase 1 power - upgrade?

So I'm pretty hands on when it comes to reading up and learning for my new build, but I'm stumped on the whole phase 1 power versus phase 3 etc.

The builder comes default phase 1, and I'm confused if and whether I need phase 3(or 2??) ppower for a new home build? I mean it'll be a rental property, thinking ducted reverse cycle air conditioning up front (even if just ducted air cond or split systems does this make a difference)?

Can anyone shed some light? Or is phase 2/phase 3 power something rare/needed for pools, which I don't plan to have in an IP?

Posed the question to ambience airconditioning in response to their quote and all I got told was needed by them at the time of my build was if I could do a 1200 x 600 concrete slab pour for the air cond unit. Otherwise no specific power or plumbing needs? A quick google seems to indicate phase 3 power being required for air conditioning, so now I'm confused? Can anyone shed some light please?

 

3 phase is for equipment that uses a lot of current Eg welding. Most houses just have single phase 240v. 3 phase is 415.
Unless you have some big gear going in or big air con unit planned you might need 3 phase.
Majority of houses have single phase, unless you have a work shop or some thing going on where you need extra power. The main thing is blokes welding
For an ip single is all you need.

 

Yes no and maybe - it depends upon your ac unit - if you are going fully ducted, then you'll require 3 phase otherwise single phase will do.

You will need to get the specs of the AC unit to confirm whether it is single or 3 phase.

Mains will need to be upgraded to 3 phase cabling from the power pole to the board, 3 phase service breakers etc.

Getting technical - if you go with 3 phase then you will want the spark to balance your loads across the phases.

 

Hmmm probably going a 10-12 kw style ducted. If i don't know, and if I can't find out prior to prestart tomorrow - what's the easiest/safest route: Go phase 1 power?

I assume it isn't cheap to upgrade to phase 3 power at pre-start , is it even possible to go phase 3 later on if required?

Otherwise will they modify the model of the air cond to suit phase 1 , or not negotiable?

 

3 phase for that size aircon unit.
It will be cheaper to get it done while building then changing it after.

 

I just upgraded from 50 amps to 3 phase. Upgrading was necessary, but I had to choose single amps 100 amps or 3 phase. By the time you had 14.5 kW air con, induction cooktop, etc we were close to the limit on 100 amps and went 3 phase. Gives us options for a granny flat or pool /spa if we want later. Cost was not much more to go 3 phase, just the cabling. We already had to upgrade the board as it was very 60s original

 

If you are ping through a builder you will probably be charged approx $1300 for the upgrade to 3 phase. Or most will include the upgrade in the cost of a full house refrigerated cooling system.

 

3 phase - if the builder has proced for the ac they should also have allowed to upgrade power based on the selection of the ac unit.

 

Thanks. Its strange as my brother didnt upgrade his nor did the air cond guy say so when i asked? I don't know if he's oblivious, surely not if that's your livelihood. I mean its an IP eventually so if i can save $1,300 on sticking with phase 1 power that would be my pref. I assume one just jumps to phase 3 power not 2 for these things?? And phase 2 is for something more specific??

Is it alot more exp to convert over to phase 3 after handover?

 

Yes, an air cond ducted reverse cycle was an upgrade option but i took the free flooring throughout and stone top... Maybe i shouldve gone the laminate in the end!

 

If it is an average sized house with average air con you won't need it, but if your building a huge house with big ducted system it would be worth while.
Sparky will work it out. It may just mean an extra circuit out two

 

For a domestic electrical installation, the only time you would need 3 phase connection to the house from the street is if you have 3 phase appliances/tools installed. ie HWS, stove, bore pump, welder, A/C etc. Check your appliance electrical specs to find out... depending upon which state in Australia single phase is 240-250volt and three phase is 415-440volt.

I hope this helps.

 

Thanks Rixter. Pre-start lady also said phase 1 was required and phase 3 for the pool etc. Never will be a pool in the backyard so no issues there, so I assume a 14kw ducted reverse cycle will get away with just average household (4x 2) appliance usage.... only a single storey too around 238sqm inclusive of garage, so don't think anyhting too big?

Hopefully I haven't got it wrong! Same for those (air conditioning guy and prestart lady) advising me...

 

The correct answer is when your maximum demand calculation ( total building load ) is 70 amps or above.

You can get a/c units upto around 16kw that use single phase.

It's the engineers responsibility to provide these details.

Max demand isn't as simple as adding everything together to get a end total. There are various factors that come into account.

Your electrical contractor is capable of working this out for you aswell.

 

Don't quibble over $1k power upgrade to 3 phase.

3 phase motors are more efficient than larger single phase equivalents hence lower running costs.

 

I was told upgrade to 3 phase power was more expensive to run in the longer term on a day to day basis over single phase?

If they say i don't need it for a 12,13 kw reverse cycle with th eeveryday applicances in the house than I should be able to get through saving the money without any large change in circumstances i.e. a massive man shed with welding tools and other high electricity usage items?

 

Have you not read the thread?