3 phase power and surge protection - urgent help needed

ssyi · Dec 07, 2019 10:33 pm

Hi All,

Originally during my colour selection appointment, my power connection was marked as single phase power connection and opted to upgrade with surge protection. The upgrade item included was - "Provide single phase, complete house overvoltage protection (surge protection) installed in the main single phase switch board - $278.00 "

But now when I received the Tender document, the builder has updated the power connection from single phase to three phase as well as increase in cost for surge protection - total of $2453.00.

Please see the individual split below :
Provide three phase power connection meter box and surface mounted three phase switch board located in the garage, in lieu of standard single phase power connection and single phase board located in the meter box - $1487.00

Provide additional run of three phase underground from the electrical supply pit located on the front right hand side of the block to the meter box located on the side elevation of Master Suite - $162.00

Provide three phase, complete house over voltage protection (surge protection) installed in the main three phase switch board - $804.00

I am seeking your help with two main questions.

1. For what kind of load someone would require 3 phase power?

Mine is a single storey 29 SQ house with gas cooktop, electric oven, regular downlights, cooling/heating of max 5KW rated power input at the peak (with E.E.R./C.O.P. of 3+ it will provide 15KW of heating / Cooling capacity), then refrigerator, air fryer, vacuum cleaner, washing machine, condenser dryer that sort of regular white goods. Will get 5KW Solar installed. No plans for pools and stuffs. Alfresco has gas supply for BBQ. I am not sure whether I will really require 3 phase power for the current use. May be future proofing of electric car charging, but won’t that work with Single phase power? If I have 3 phase power, I guess as per the rule I should have the 3 phase inverter. In that case my solar power generation would be split in to 3 phases and I may not able to ensure that my air conditioner would receive all the available power from solar. Won’t that create a situation where the phase line used by air conditioner would have to draw extra power from power grid (high cost of 0.3 cents / unit) whereas the other 2 idle phases would feed ( only 0.1 cents / Unit credit for feed in) in the surplus unused solar energy to the Grid. Even if I use 3 phase air conditioner, I am unable to equate solar vs usage requirements. Aren’t these complications because of 3 phase power. Please correct me if I am wrong here.

2. Do you think what my builder quoted for 3 phase power supply and the surge protection looks alright? Is there anything that could be done post the handover cheaper than the rates from the builder (like the entire thing or even just the surge protection) ?

Your quick help will be highly appreciated as I will have to decide whether to go with a) three phase power connection and b) three phase surge protection Monday end of Day.

Thanks,

aussieta · Dec 08, 2019 10:55 am

imo
the 15kw ac is probably why the need for 3 phase
yes you should get 3 phase solar inverter only a few hundred $ more
unsure why the 3 phase surge is so expensive, but i would still get it

Shi · Dec 08, 2019 11:47 am

Thank you aussita. By the way, my plan was to put a single phase AC.

Just wondering when we say 15KW AC, it is the heating/cooling power right with efficiency of 3+.

Say if the heating/cooling range is 15KW max to 6 KW minimum, the actual max rated power utilization would be 5KW (corresponding to 15KW heating) and minimum would be 2KW (corresponding to 6KW heating being the lowest).

Now when calculating the Amps corresponding to the maximum power, i.e for 5KW with power factor of 0.9, maximum Amps would be somewhere 25 amps. If I am not wrong, single phase maximum amps is 100 amps right.

That means I still have 60 to 70 amps available before reaching the threshold. Would I be ever exceeding the threshold using other generic white goods.

aussieta · Dec 08, 2019 3:12 pm

what is the model number of the ac unit you are planning on

Shi · Dec 08, 2019 3:59 pm

Hei Aussieta,

Considering mine is a single storey and my builder only had the Brivis options, I'm planning to install the refrigerated cooling post the handover. Haven't finalized yet, but below are the few shortlisted ones.

Mitsubishi Heavy Industries FDUA140AVNXVF-RC-EX3 14.0 kW 1 Phase Ducted System
https://www.lawsonair.com.au/mitsubishi ... ted-system

Panasonic S-140PE1R5B 14.0kW Ducted 1 Phase Ducted System Air Conditioner
https://www.lawsonair.com.au/panasonic- ... ted-system

Mitsubishi Electric PEA-RP140GAA 14.0 kW 1 Phase Ducted Unit
https://www.lawsonair.com.au/mitsubishi ... -1-phase-d

Daikin FDYQ140 14.0kW Premium 1 Phase Inverter Ducted Unit
https://www.lawsonair.com.au/daikin-fdy ... onditioner

Thanks,

Joker · Dec 09, 2019 9:14 pm

Have actron add on ac 17kw single phase,,never a problem ,home almost 50squares, with 2-3 zones on when used,4zones all up,have 5kw micro inverted solar,was almost going with 3phase,but found I didn't need it,if in doubt go for it,does sound a bit high ,but not sure what's involved with surge protection and quality.

Shi · Dec 09, 2019 10:52 pm

Thank you Joker. I'm in the same boat, can't foresee any reason why 3 phase would be required for my case other than fast charging electric car if I ever buy it.

supersleuth · Dec 10, 2019 1:16 pm

Shi

Thank you Joker. I'm in the same boat, can't foresee any reason why 3 phase would be required for my case other than fast charging electric car if I ever buy it.

Hey Shi,

I'm in a similar situation building new home and decided to go 3 phase. Mine is probably a stronger case as I already have an EV, but something you should consider some states (like QLD) limit single phase homes to 5kw solar feed-in/export, whereas 3 phase homes can export 15kw. So in future if you want to upgrade your solar panels, you may find that limitation an issue.

There are also other benefits to 3 phase such as better balance of current draw in the house which a sparky can explain better then me.

You can certainly charge an EV on single phase (I have been for several months) but in time when you potentially have 2 EVs needing a charge, or just want to charge quicker from time to time, I think I would regret not having 3 phase available.

Of course all depends on your personal circumstances.

I've gone for 3 phase ducted A/C, 3 phase solar inverter, and 3 phase to garage for 2 x EV charging points. Plus 3 phase to pool area for future pool heater.

Shi · Dec 10, 2019 2:25 pm

supersleuth

Shi

Thank you Joker. I'm in the same boat, can't foresee any reason why 3 phase would be required for my case other than fast charging electric car if I ever buy it.

Hey Shi,

I'm in a similar situation building new home and decided to go 3 phase. Mine is probably a stronger case as I already have an EV, but something you should consider some states (like QLD) limit single phase homes to 5kw solar feed-in/export, whereas 3 phase homes can export 15kw. So in future if you want to upgrade your solar panels, you may find that limitation an issue.

There are also other benefits to 3 phase such as better balance of current draw in the house which a sparky can explain better then me.

You can certainly charge an EV on single phase (I have been for several months) but in time when you potentially have 2 EVs needing a charge, or just want to charge quicker from time to time, I think I would regret not having 3 phase available.

Of course all depends on your personal circumstances.

I've gone for 3 phase ducted A/C, 3 phase solar inverter, and 3 phase to garage for 2 x EV charging points. Plus 3 phase to pool area for future pool heater.

Thank you supersleuth !

Were your builder charged the similar amount for 3 phase ? I am probably leaning towards 3 phase and planning to leave the surge protection for now. My builder charges $800 for surge protection, instead I am planning to do it along with my post handover electric jobs such as extra downlights and power points.

supersleuth · Dec 10, 2019 3:04 pm

Shi

supersleuth

Shi

Thank you Joker. I'm in the same boat, can't foresee any reason why 3 phase would be required for my case other than fast charging electric car if I ever buy it.

Hey Shi,

I'm in a similar situation building new home and decided to go 3 phase. Mine is probably a stronger case as I already have an EV, but something you should consider some states (like QLD) limit single phase homes to 5kw solar feed-in/export, whereas 3 phase homes can export 15kw. So in future if you want to upgrade your solar panels, you may find that limitation an issue.

There are also other benefits to 3 phase such as better balance of current draw in the house which a sparky can explain better then me.

You can certainly charge an EV on single phase (I have been for several months) but in time when you potentially have 2 EVs needing a charge, or just want to charge quicker from time to time, I think I would regret not having 3 phase available.

Of course all depends on your personal circumstances.

I've gone for 3 phase ducted A/C, 3 phase solar inverter, and 3 phase to garage for 2 x EV charging points. Plus 3 phase to pool area for future pool heater.

Thank you supersleuth !

Were your builder charged the similar amount for 3 phase ? I am probably leaning towards 3 phase and planning to leave the surge protection for now. My builder charges $800 for surge protection, instead I am planning to do it along with my post handover electric jobs such as extra downlights and power points.

Sorry I should have mentioned I have arranged my own sparky to do all electrical as part of the building contract. Its almost no difference for me but builder would add on their margin so that might change things. For what it's worth my sparky has not said anything about recommending surge protection so I guess he thinks that money is better spent elsewhere.

I would say 3 phase will help future proof your house, and a surge protector could easily be added later.

My sparky spoke very highly of the benefits of 3 phase - he convinced me to upgrade the solar inverter to 3 phase and also the ducted air. And he is a friend so its all mates rates - no benefit in it for him either way.

ssyi · Dec 10, 2019 3:24 pm

Thanks great supersleuth !

ssyi · Dec 10, 2019 3:25 pm

shi

Thanks great supersleuth !

TeslaCyberTruck · Jan 03, 2020 2:50 pm

supersleuth

Shi

Thank you Joker. I'm in the same boat, can't foresee any reason why 3 phase would be required for my case other than fast charging electric car if I ever buy it.

Hey Shi,

I'm in a similar situation building new home and decided to go 3 phase. Mine is probably a stronger case as I already have an EV, but something you should consider some states (like QLD) limit single phase homes to 5kw solar feed-in/export, whereas 3 phase homes can export 15kw. So in future if you want to upgrade your solar panels, you may find that limitation an issue.

Hey supersleuth - which EV do you own? Who did you use for your roof & inverter & say Tesla PowerWall2 battery install? I am hearing a lot of good things about Solaray - as I keep hearing that the SII (solar install industry) is full of sharks

TeslaCyberTruck · Jan 03, 2020 2:54 pm

Shi

supersleuth

Shi

Thank you Joker. I'm in the same boat, can't foresee any reason why 3 phase would be required for my case other than fast charging electric car if I ever buy it.

Hey Shi,

Thank you supersleuth !

Were your builder charged the similar amount for 3 phase ? I am probably leaning towards 3 phase and planning to leave the surge protection for now. My builder charges $800 for surge protection, instead I am planning to do it along with my post handover electric jobs such as extra downlights and power points.

Hey Shi - I think definitely worth to straight away go with 3-phase because also a bonus with 3-phase if the grid (normal elec) goes down around you and you have a battery (eg: Tesla PowerWall2) install in your garage or outside in an area with a little bit of roof-cover, your house will lose elec for about 1-second and then the PowerWall2 battery will kick-in and use whatever is stored in that. The Tesla PowerWall2 is only about high $9000's so well worth if one has the funds

Is your home builder installing your roof solar panels and the inverter, or are you getting an independent like Solaray to install it after the house build is complete?

Shi · Jan 03, 2020 3:32 pm

Yes TeslaCyberTruck, I have included 3-phase. Only regular solar for the water heater and an additional solar pannel as per the developer requirements are installed by the builder.I am planning to have the complete home solar from outside. PowerWall2, hmmm it would long time to break even.

supersleuth · Jan 03, 2020 3:48 pm

TeslaCyberTruck

supersleuth

Shi

Thank you Joker. I'm in the same boat, can't foresee any reason why 3 phase would be required for my case other than fast charging electric car if I ever buy it.

Hey Shi,

I'm in a similar situation building new home and decided to go 3 phase. Mine is probably a stronger case as I already have an EV, but something you should consider some states (like QLD) limit single phase homes to 5kw solar feed-in/export, whereas 3 phase homes can export 15kw. So in future if you want to upgrade your solar panels, you may find that limitation an issue.

Hey supersleuth - which EV do you own? Who did you use for your roof & inverter & say Tesla PowerWall2 battery install? I am hearing a lot of good things about Solaray - as I keep hearing that the SII (solar install industry) is full of sharks

Hey TCT. My EV is a Telsa 3. The solar system is part of home build contract so not sure who they are using. its a 5kw system and after paying to upgrade to 3 phase inverter, discovered it was still only 5kw inverter so i reverted to standard single phase. For a higher power 3 phase inverter it was quite a bit more, so I'm just going with the standard and when i add more panels i'll add another single phase inverter on a different phase.

Havent got a powerwall yet. I can't justify the price of the battery yet - the ROI is decades I believe.

TeslaCyberTruck · Jan 03, 2020 4:58 pm

Shi

Yes TeslaCyberTruck, I have included 3-phase. Only regular solar for the water heater and an additional solar pannel as per the developer requirements are installed by the builder.I am planning to have the complete home solar from outside. PowerWall2, hmmm it would long time to break even.

If you look at Tesla PowerWall2 on pure on the surface break-even yes it may take a while, but if you look at the tangibles such as having elec when others around dont have it (grid goes out for some reason) or if someone in your house needs elec & internet 24/7 (like a small business run from home, or drop shipping business, or similar) it could be well worth it, and also can make a bit of $'s by selling the battery stored elec back to the grid. Because with a 3-pahse you can export more kWh back to to grid

TeslaCyberTruck · Jan 03, 2020 5:17 pm

supersleuth

TeslaCyberTruck

supersleuth

Hey Shi,

I'm in a similar situation building new home and decided to go 3 phase. Mine is probably a stronger case as I already have an EV, but something you should consider some states (like QLD) limit single phase homes to 5kw solar feed-in/export, whereas 3 phase homes can export 15kw. So in future if you want to upgrade your solar panels, you may find that limitation an issue.

Hey supersleuth - which EV do you own? Who did you use for your roof & inverter & say Tesla PowerWall2 battery install? I am hearing a lot of good things about Solaray - as I keep hearing that the SII (solar install industry) is full of sharks

Hey TCT. My EV is a Telsa 3. The solar system is part of home build contract so not sure who they are using. its a 5kw system and after paying to upgrade to 3 phase inverter, discovered it was still only 5kw inverter so i reverted to standard single phase. For a higher power 3 phase inverter it was quite a bit more, so I'm just going with the standard and when i add more panels i'll add another single phase inverter on a different phase. Haven't got a powerwall yet. I can't justify the price of the battery yet - the ROI is decades I believe.

Yeah true - as I said in the above reply to Shi, if you look at Tesla PowerWall2 on a pure on the surface ROI (break-even) it may take a while, but intangibles such as having electricity while others around you don't, or if someone in your household runs a small business from home (eg: drop shipping, similar), and with 3-phase being able to sell a big amount of kWh unused battery power back to the grid can also earn one some extra $'s, then the PowerWall2 is worth its weight in gold

Re: Tesla Model 3 - do you regularly watch (or follow) the Aussie-based Tesla EV owner YouTube channel's like below?
* Tesla Tom
* Tesla Straya
* Chris Vanderstock
* SydEV
* AHillFromOz
* Unplugged EV
* Rado Trenciansky
* Wonk
* Telsa from the Gong
* Outback Tesla
* Jonathan Choo
* Millin Tesla Taxi
* Ahead of the Curve
* JD Solar & EV
* Kane & Pia
* TechAU
* ku7 tech
* LocalPower4101
* Harald Murphy
* Paul Colmer

Blacktea2sugars · Jan 03, 2020 6:26 pm

Builder may have done it for a reason, like ours did.
We have an induction cooktop and aircon that requires 3 phase.

Also we were told to "future proof" our home as much as possible too, during the build.
So we are taking into account the "things that will get added", and 3 phase was the result.

I think your costs are extremely reasonable. Ours was 3800+

TeslaCyberTruck · Jan 03, 2020 6:51 pm

Blacktea2sugars

Builder may have done it for a reason, like ours did.
We have an induction cooktop and aircon that requires 3 phase.

Also we were told to "future proof" our home as much as possible too, during the build.
So we are taking into account the "things that will get added", and 3 phase was the result.

I think your costs are extremely reasonable. Ours was 3800+

Hey Blacktea2sugars - who was your builder and which suburb/area (& state) did you build in?