Building a new house, being prepared

[Vostok]

Coal-fired power stations can't be turned on and off. Gas powered stations can be more demand driven. NSW is around 80% coal (at least was in 2018/19) and coal-fired power stations run 24x7 with little scope for changing their output as demand changes. They certainly can't lower production when a few roof-top solar system export to the grid.

Coal-fired output can be modulated though - and it is - in response to demand changes. In the olden days, even things like ad-breaks in the top-rating TV programmes of the day would lead to demand spikes when hundreds of thousands people simultaneously went to the kitchen and turned their kettles on. And back in those days they didn’t have fast-response gas-peakers like we do now. So generator operators used to closely track these things and pre-emptively inject more power into the grid. It wasn’t instantaneous response by any means, but enough to prevent voltage drop and frequency instability.

And it’s not just a “few” rooftop solar systems but the collective output of hundreds of thousands of rooftop systems that makes a difference to fossil demand.

In January, NSW was 29% renewable and 67% coal:

National and State Renewable Energy stats

 

[Vostok]

The SA switchoff only applies to new systems installed after (for memory) 1 july last year. It does not apply to systems installed before that. Applies to upgrades and size increases too, so a lot of people installing batteries will get caught with it as well.

This is why we need a smart grid with smart inverters. Rather than shutting rooftop solar inverters off when there is voltage rise, a “smart grid“ would simply dial down their output enough until the collective export no longer caused voltage rise, i.e. production meets demand.

That way everyone would share the “pain” (and still be meeting their own household demand) rather than blunt-force trauma of having their solar production reduced to zero AND their house back to running off the grid (which in most cases is not 100% renewable).

What this policy will do is encourage more battery uptake - because it improves battery economics.

 

[Victor T]

hmm for me when I built my house I did certainly opt for 3 phase power.... I have 13kw Jinko 335w half type panels 39 panels.. with Sunnyboy 3 phase 10kw inverter.....

Didn't install those fancy wall chargers.. I just opt for 2 Dedicated 15A plug at the garage 1 on each side( with 16A circuit breaker)... and I bought a $250 16A portable charger for the car to charge.. 16A with 240v is about 3840w if you got 2 electric charging together is about nearly 7680w.....inverter max is only 10000w and it's between 10 to 2 pm mostly.... 16A charging can charge like 26km/hour easily done with a few hrs charging for daily commute.

I set my charging to 10am charging because by 10am I would get at least 4000w in generation even if it seems cloudy..... I work from home mostly

didn't get the batteries because it's not worth the cost....

If it's not too late for you to change..... Depending on your preference.... I did regret not going 100% electric for my new house.... I still have ducted gas heating and gas instantaneous hot water....... I could have cut off gas altogether.

 

[suku18]

Thanks to everyone for sharing their thoughts on my question.

Is anyone able to send a picture of how the Gen 3 charger is connected to the the circuit breaker on the wall? Or how the set ups should look like in the Garage.
We have started our internal wiring and tomorrow I am meeting the electrician to show him my Gen 3 charger and ask him to make some connections.

to confirm we will have 3 phase connection to the house.

 

[cafz]

Thanks to everyone for sharing their thoughts on my question.

Is anyone able to send a picture of how the Gen 3 charger is connected to the the circuit breaker on the wall? Or how the set ups should look like in the Garage.
We have started our internal wiring and tomorrow I am meeting the electrician to show him my Gen 3 charger and ask him to make some connections.

to confirm we will have 3 phase connection to the house.

It's a wired-in device. It has ingress points for conduit on top and bottom, the sparky pulls the wiring through into it and screws it into a connection block on the back plate of the Gen 3.

There are diagrams in the Gen 3 Wall Connector Installation Manual AU/NZ - send that to your electrician.

 

[suku18]

It's a wired-in device. It has ingress points for conduit on top and bottom, the sparky pulls the wiring through into it and screws it into a connection block on the back plate of the Gen 3.

There are diagrams in the Gen 3 Wall Connector Installation Manual AU/NZ - send that to your electrician.

Thanks, and apologies for my noviceness.

But what is this and do I need this

 

[moa999]

That's an isolation switch, which afaik you need in Australia unless the wall charger is literally next to the fuse board.

 

[cafz]

That's an isolation switch, which afaik you need in Australia unless the wall charger is literally next to the fuse board.

Opinions among electricians seem to vary. I asked mine about it before installation - he looked into it and said it wasn't required.

 

[ambishop]

2 things to consider. 3 phase junction box located in an area that can reach 2 cars. Mine is mounted on the side wall in the same location as the charging port and with the long cable can reach two cars.

If you prefer 2 wall chargers I would not put both on the same breaker.

Ensure you drop in ethernet cable to support wifi in the garage with wifi access point. I suggest power point near ethernet port as well.

Lastly, having a gen 2 wall charger on 3 phase charges pretty fast. I leave one car on UMC and the other on wall charger. Then switch if needed.

With 13 kw solar I wanted a max charge rate of both cars to use 100% solar.

In summer I can charge both cars during day 100 % solar and switch cables if desired

Also have 24 amp single phase hardwire connection for UMC at shed

Happy to give further advise or photos etc as just outside Canberra myself

 

[ambishop]

24 or 32 amp UMC hardware connection to ISO switch is also a good option if you do not want wall charger. 32 amp hardwire will charge at 7kwh. Mine is only 24 as it is connected to my solar array with battery backup.

 

[Zoltrix77]

Opinions among electricians seem to vary. I asked mine about it before installation - he looked into it and said it wasn't required.

I am a non practicing electrtician, and I really suprised that an electrician can come to the conclusion that an isolator is not required. I mean, I am not particularly worried if they don't choose to install one, but I wouldn't. I have just tried to satisfy my curiosity by spending 30 minutes reading the Wiring Rules (AS/NZS 3000:2018), and while I can't find anything specific for this particular case:

1. It's common practice to install an isolator (switch) on any directly connected electrical equipment, there is only on exception that I am aware of; and that is an oven or microwave (that being an enclosed cooking device), which come to think of it is a little odd in itself. Generally the idea is to be able to swtch off the device whist someone is working on the equipment for safety (may or may not be electrical related safety, eg moving parts etc)

2. All socket outlets (with the exception of one installed for the specifically for the purpose of a luminaire) are required to have a switch. I'd consider an EV charger to be close enough to a socket outlet. There is a whole appendix on EV chargers in current rules, it makes specfic mentions of "socket-outlets" being one form of connection, and "vehicle connectors" being aother. Basically, if you have provided a socket outlet for the purposes of pluging in a portable EVSE (or Fixed EVSE but you have attached a plug to the input), that is the socket-outlet method. If you connect via a Type 1 or Type 2 connector, that is a "vehicle connector" method.

3. I would feel better if it was possible to quickly switch off power both for convinience and for a possible safety issue should somthing untoward be happening.

4. If your electrical install is randomly audited, I would expect an inspector to defect the job, regardless of wether or not its techinically required. Just for the fact that he/she might not be sure either and would err on the side of caution. You could try to convince them otherwise, but if they didn't agree, you'd be going back to install an isolator, wasting time, paying for an isolator you didn't charge the customer for, looking like an idiot to the customer and potentially having to completely change the position of the charger etc.

5. As the customer, I'd ask for an isolator just to avoid potential hassels as listed in point 4.

6. The rules should just remove the question by specifying one way or another!!!

No idea if I am right or not, but thats my take.

 

[cafz]

1. It's common practice to install an isolator (switch) on any directly connected electrical equipment, there is only on exception that I am aware of; and that is an oven or microwave (that being an enclosed cooking device), which come to think of it is a little odd in itself. Generally the idea is to be able to swtch off the device whist someone is working on the equipment for safety (may or may not be electrical related safety, eg moving parts etc)

Pretty sure my AC doesn't have an isolator switch either (of course I've seen plenty around that do have them). Electric HWS often don't seem to have them. On the other hand I have seen wired-in ovens with isolator switches in newer builds (often hidden at the back of a nearby cupboard, which kind of defeats the point a little doesn't it?).

If I want to deenergise the AC or car charger for safety, I'll use the RCBO (they're both on dedicated circuits).

 

[Zoltrix77]

Pretty sure my AC doesn't have an isolator switch either (of course I've seen plenty around that do have them). Electric HWS often don't seem to have them. On the other hand I have seen wired-in ovens with isolator switches in newer builds (often hidden at the back of a nearby cupboard, which kind of defeats the point a little doesn't it?).

If I want to deenergise the AC or car charger for safety, I'll use the RCBO (they're both on dedicated circuits).

Definately AC and HWS require isolation switches. It will just be old installations that don't have them. If the AC or HWS were to be replaced, the electrician would probably fit an isolator, but I'd have to check if that is a hard requirement. Eg, if you extend a power circuit, the new GPO must be RCD protected, Usually the easiest way is to put an RCD in the switchboard, but you CAN just put an RCD protected GPO in), I guess most electrtcians would up sell a complete new switchboard.

The oven rule can be confusing. If there it is an electric cooktop, or an oven with a built in cook top, it DOES require an isolator within easy reach, but not requiring you to reach over the cooking surface. Same applies to built in fryers etc. A purely enclosed oven only does NOT require an isolation switch, however, should you choose to install one, thats obviously fine too, some electricians will install one because they think it is a good idea, or they don't understand the requirements. Being at the back of a cupboard is not acceptable if it is an open cooking serface, but is if its an enclosed oven. Gas cooktops with electronic ignition don't have to have a readily accesable switch either, but they DO require an isolation in the cupboard, usually a GPO.

Requirements are change every few years, HWS isolators are now required to disconnect all live conductors, eg, including the neutral. Its recomended on other isolators. So basically every isolator is now 2 pole.

On your last point, yes you can use RCBO, but the idea is that people may not have a clue where the switchboard is located in an emergency.

 

[suku18]

So another question. My electrician said he will be putting one thick single-phase wire to the circuit breaker switch and not three wires for the 3 phase connection. He also mentioned if you need a 3 phase connection to the wall charger you need to run three wires which will cost much much more. It has now got me confused as do I need to run one thick single phase wire to the charger or three wires ?
Please any advise would be much appreciated.

 

[Nobody Famous]

So another question. My electrician said he will be putting one thick single-phase wire to the circuit breaker switch and not three wires for the 3 phase connection. He also mentioned if you need a 3 phase connection to the wall charger you need to run three wires which will cost much much more. It has now got me confused as do I need to run one thick single phase wire to the charger or three wires ?
Please any advise would be much appreciated.

Did he quote in writing the variation you mentioned here Building a new house, being prepared

How long was you cable run from Breaker to Outlet?

 

[paulp]

So another question. My electrician said he will be putting one thick single-phase wire to the circuit breaker switch and not three wires for the 3 phase connection. He also mentioned if you need a 3 phase connection to the wall charger you need to run three wires which will cost much much more. It has now got me confused as do I need to run one thick single phase wire to the charger or three wires ?
Please any advise would be much appreciated.

Single phase is 3 cables comprising an active, neutral, and earth. 3 phase is 3 actives and the neutral can be dropped to earthing, so you run 3 actives Instead of 1 hence a 4 strand cable instead of 3 strand. Each of these can be run as a single cable or as multiple cables. The labour cost is identical for both. Only difference is the cable cost. Its not “much much more“, although everyone has a different view on value And depends how much of it your are buying and how many amps you intend putting through it.
A tesla hpwc that is 3 phase will run at reduced capacity connected on single phase.

 

[Rolond]

3 phase is 3 actives and the neutral can be dropped to earthing
Err... No!!
A Tesla HPWC requires a neutral, and the earth can not double as a neutral, the AC charger in the Tesla is not a three phase charger as such but three single phase chargers in effect

 

[Nobody Famous]

Please any advise would be much appreciated.

On further thought, maybe just get a 15A GPO and a conduit that you can pull cables later. Might avoid getting gouged on price and not getting what you want. Install a Gen3 later if/when.

 

[suku18]

Did he quote in writing the variation you mentioned here Building a new house, being prepared

How long was you cable run from Breaker to Outlet?

Hi,
Nothing in writing. So have been dealing directly with the electrician so the builder is not involved and wont be charging any variation.

 

[suku18]

Thank you everyone. I now have a decent understanding of what i want.
What the electrician has quoted me will be for a single phase cable run, so considering a 32 A circuit the max I can attain is 50 km/ hour with the Gen 3 Wall charger. As per the table from the Tesla Website.

But a 3PHASE RCD + 3PHASE isolation switch + 3PHASE cable required pending the amperage from the meter board should supply around 75 km / Hour of charging speed.

This makes sense now. I will ask him to quote for the 3 Phase connection. Else will try other quotes.

Thanks everyone for your help. This group has been awesome.