Key takeaways
- An EV charger is a continuous load that has to be assessed against the whole installation, not added to the spare ways and forgotten.
- The supply capacity, the switchboard location and the cable route are design decisions that must be settled before rough-in, because moving any of them after sheeting is expensive.
- BASIX sets the water and energy performance requirements that apply to the dwelling, and the electrical design has to be able to deliver what the certificate commits the building to.
- On a new build the builder is the principal contractor, so electrical safety obligations sit with the site and the trade, not with the future owner.
- Making provision for a future charger at rough-in is almost always cheaper than retro-fitting one after practical completion, even when the charger itself is not installed.
Most of the cost in an EV charger installation is not the box on the wall. It is getting the circuit from the switchboard to the car, and making sure the supply can carry it. On a new build both of those problems are still open while the frame is exposed, which is why the rough-in stage is where the decisions belong.
Builders often treat the charger as an appliance choice — something the owner picks after handover. By then the cable route is behind plaster, the switchboard is full, and the only options left are surface conduit or a supply upgrade. Neither is cheap, and neither is the builder’s fault if nobody planned for it.
This article covers the rough-in and load planning side of EV charging in a new NSW dwelling. It does not cover converting an existing home to all-electric operation, which raises different questions about gas appliances and existing switchboards.
Why an EV charger is a load problem, not a power point
A charger draws a large, steady current for hours. That behaviour is different from a kettle or an oven, which draw hard for a short time. A steady load of that size has to be assessed against the whole installation, because it runs at the same time as everything else in the house — often overnight, when the household is also running hot water, air conditioning and whatever else is on the tariff.
The practical consequence is that the spare ways in the switchboard tell you very little. A board can have room for another circuit breaker and still not have the supply capacity to carry a charger at full rate alongside the rest of the dwelling. The assessment that matters is the total connected load and how it is managed, not the physical space in the enclosure.
This is also where the charger type starts to matter, because different chargers draw differently and some can be set to a lower rate. A charger that can be limited is a different design problem from one that always draws its maximum. Settle that with the client early, because it changes the cable and the protective device.
What BASIX actually commits the dwelling to
BASIX is the NSW planning framework that sets water and energy performance requirements for new dwellings and some alterations. It applies through the planning approval process, which means the commitments made in a BASIX certificate become conditions the building has to satisfy. You can read the framework on the NSW Planning Portal BASIX page, and the way it interacts with approvals is set out in the guidance on BASIX and planning approvals.
For an electrical rough-in, the point is not to memorise the certificate. It is to understand that the energy commitments in the approval are real, and that the electrical design has to be capable of delivering them. If the certificate assumes certain appliances or certain metering, the rough-in has to support that. Discovering at fit-out that the electrical layout cannot deliver what the certificate promised is a problem with the certifier, not just the electrician.
BASIX does not, on its own, require an EV charger. It sets performance requirements. Whether an EV charger is required or incentivised depends on the current rules and on the specific development, and those rules change. Check the current requirement against the approval for the job rather than relying on what applied last year.
Supply capacity: the question that decides everything else
Before anyone promises a charger circuit, someone has to answer a simple question: how much capacity is actually available at this supply? That is a job for the electrician, working from the network connection and the intended loads, not a guess made on site by counting empty ways.
Where capacity is tight, there are several ways forward, and they have different cost profiles. The load can be managed so the charger only draws at full rate when the rest of the house is quiet. The charger can be set to a lower rate permanently. The supply can be upgraded. Each of these has a different impact on the client’s budget and on what the rough-in needs to include.
The mistake is to leave this question until the charger is being installed, because by then the client has already chosen the charger and expects it to work at full rate. If the answer turns out to be a supply upgrade, that is a conversation nobody wants to have after handover. Sorting it at design stage means the client can make the call with real information, and the rough-in can be built to suit.
Rough-in sequence for an EV-ready dwelling
- 1Confirm the supplyEstablish the size of the incoming supply and what capacity is genuinely spare before promising a charger circuit.
- 2Fix the charger locationDecide which side of the garage or carport the vehicle will be plugged in, and whether one point or two is needed.
- 3Plan the cable routeRun the route from switchboard to charger point while the frame is open, including any wall penetrations and fire-rated elements.
- 4Size the circuitHave the electrician size the protective device and cable for the charger type and the load it will draw.
- 5Install the physical provisionFit the cable, conduit, mounting provision and any isolation point, even if the charger itself is not being supplied yet.
- 6Record and hand overDocument what was installed, what it is rated for, and what the owner needs to know before they buy a charger.
Location: where the car will actually be plugged in
Charger location is not the same as “in the garage”. It depends on which side of the vehicle the charge port sits, how the car is parked, and whether the cable has to reach across a walkway. Get this wrong and the owner ends up draping a cable over the floor every night.
On a new build, the cheapest thing you can do is decide the location early and mark it on the electrical plan. That sounds trivial, but it forces the conversation while the answer is still free. Once the garage is lined, the location is fixed by where the cable was run.
There are practical constraints to work through at the same time. The charger needs to be mounted where it will not be hit by a vehicle, where it is not exposed to direct weather if the carport is open, and where the cable does not create a trip hazard. If the dwelling has two vehicles, consider whether a second point is likely, because running the provision for two while the walls are open costs far less than adding the second later.
If the garage is attached and the switchboard is inside the dwelling, the route also has to respect the separation between the two. That is a detail for the electrician, but the builder needs to know it is a constraint so the location is not locked in before it is checked.
The switchboard question: how much provision is enough
There is a spectrum between “nothing” and “fully installed charger”, and the right answer depends on the client. At one end, the rough-in includes only the cable and a mounting provision, with the charger and its circuit added later. At the other, the whole installation is completed at handover.
The middle ground is the one most clients actually want: the cable is run, the circuit is provisioned, an isolation point is fitted, and the charger is left for the owner to buy. That gives them the choice of charger without paying for one the builder picked. It also means the expensive part — getting the cable to the right place through a finished building — is already done.
Whichever option is chosen, the switchboard needs to be able to accommodate it. That includes physical space for the protective device and any control equipment, and it includes the load capacity question from earlier. A board that is physically full at handover is a board that has to be replaced or extended to add the charger, which is exactly the cost the rough-in was meant to avoid.
There is also a documentation point. Whatever was installed needs to be recorded on the as-built drawings and in the handover information, including what the circuit is rated for and what the owner needs to know before buying a charger. Without that, the next electrician is guessing.
Checks before the walls are sheeted
- Supply capacity assessed against the total connected load, not just the spare ways in the board.
- Charger location agreed with the client and marked on the electrical plan.
- Cable route run and protected, including penetrations through fire-rated or structural elements.
- Dedicated circuit and protective device sized for the charger, not for a general-purpose outlet.
- Isolation and control arrangement agreed, so the charger can be managed rather than simply tripped.
- Provision documented on the as-built drawings and in the handover pack.
- Future second vehicle point considered if the household runs two cars.
Coordination with other trades at rough-in
An EV charger circuit is not the only thing competing for space in the frame. Solar and battery systems, air conditioning, smart wiring and data all want a route from the switchboard to somewhere else. Running them as separate exercises means the frame gets opened more than once, and the routes start to conflict.
If the job includes a battery or solar, the charger circuit and the energy system need to be planned together, because the way they interact affects the load management approach. There is a related article on the builder’s role in home battery installation that covers how that coordination works. If the job includes ducted or split air conditioning, that has its own clearance and cable requirements, covered in the article on split-system air conditioner installation in NSW.
Smart wiring and data are also worth settling at the same time, because the charger may need a data connection for scheduling or monitoring. That is covered in the article on smart home wiring rough-in decisions. The principle across all of them is the same: decide the routes once, while the frame is open, and make sure each trade knows what the others are running.
Safety and the principal contractor’s obligations
Electrical work on a construction site carries risk, and the builder as principal contractor has obligations that do not disappear because the work is being done by a licensed trade. Safe Work Australia publishes national guidance on electrical safety that sets out the general duties and the controls expected on site; the principles are relevant to how the electrical rough-in is managed, including isolation, testing and the condition of tools and leads.
The specific risk on an EV rough-in is that the cable is installed before the charger exists, which means there is a live or provisioned circuit with no appliance on the end of it. That has to be managed so nobody assumes the circuit is dead because the charger is not there. Labelling at the board and at the point is part of that.
There is also a commissioning question. If the charger is installed at handover, it needs to be tested and verified before the owner uses it. If it is not installed, the handover information needs to be clear about what has and has not been done, so the owner does not assume the circuit is ready for any charger they happen to buy.
The mistake that costs the most. Running a charger circuit without first confirming the supply capacity. The cable is cheap; discovering after handover that the supply cannot carry the load, and that the client has already bought a charger, is not.
Worked example: a builder in western Sydney
A builder in western Sydney is putting up a single-storey dwelling with an attached double garage. The client mentions during selections that they expect to buy an electric vehicle within a couple of years and want to be ready for it.
The builder does the sensible thing and raises it with the electrician before the frame is closed. The electrician assesses the supply and finds that a full-rate charger alongside the rest of the intended load would be tight. The client is given the options: provision the circuit and manage the load so the charger only draws at full rate when the house is quiet, or plan for a supply upgrade now.
The client chooses the managed approach, because it avoids the upgrade cost and suits their charging pattern. The rough-in includes the cable run to the agreed location on the driver’s side of the garage, a dedicated circuit provisioned at the board, and an isolation point. The charger itself is not installed, because the client wants to choose it later.
Two years later the client buys a vehicle and a charger. The electrician returns, fits the charger to the existing provision, sets the load management, and commissions it. The total cost is a fraction of what a retrofit would have been, because the cable route and the board provision were already there.
The counterfactual is easy to picture. If the builder had not raised it, the garage would have been lined with no provision. The client would have bought a charger, discovered the supply constraint, and faced a choice between surface conduit through a finished garage and a supply upgrade. Either way the conversation would have been about extra cost, and the builder would have been the one explaining why nobody mentioned it.
None of this required predicting the future. It required asking the question while the answer was still cheap.
What to put in the handover pack
If the charger is not installed at handover, the owner needs enough information to buy the right one and to brief the electrician who fits it. That means a record of the circuit, its rating, the location of the provision, and any load management that has been set up.
It also means being clear about what has not been done. A provision is not an installation, and the owner should not assume that any charger will simply plug in. The handover information should say what the provision is designed for and what needs to be checked before a charger is connected.
For the builder, this is also a risk management step. A clear record of what was provided, and what was left to the owner, is the difference between a reasonable scope boundary and an argument about expectations. It costs very little to write down and it is worth a great deal if the owner later claims they were promised a working charger.
Where this sits in your CPD
Electrical rough-in decisions sit at the intersection of compliance, trade coordination and client expectation, which is exactly the territory that NSW builder CPD is meant to cover. If you want to understand how the requirements are structured and what counts, the guide to how NSW builder CPD works is a useful starting point.
The broader catalogue of courses is at the PointCPD course catalogue, and the home page at PointCPD is the entry point for NSW builder CPD courses. The point of covering this material is not to turn builders into electricians. It is to make sure the conversation with the electrician happens before the frame is closed, because that is where the cost is decided.
Questions builders ask
Do I need to install an EV charger in a new home in NSW?
Not necessarily. BASIX sets water and energy performance requirements for the dwelling, but it does not on its own require an EV charger. Whether a charger is required or encouraged depends on the current rules and the specific development, so check the approval for the job rather than assuming.
Can I just run a cable and sort the switchboard out later?
You can run the cable, but the switchboard provision and the load assessment should happen at the same time. If the board has no capacity for the circuit, or the supply cannot carry the load, the cable alone does not solve the problem. Settle both before the walls are sheeted.
How do I know if the supply can carry an EV charger?
That is an assessment for the electrician, working from the network connection and the intended loads in the dwelling. It is not something you can judge from the number of spare ways in the board. Get the answer before you commit to a charger location or a charger type.
What is the difference between a provision and an installed charger?
A provision means the cable, circuit and mounting point are in place but the charger itself is not fitted. An installed charger is fully connected, tested and commissioned. The provision is cheaper at handover and leaves the charger choice to the owner, but the handover information needs to be clear about what has and has not been done.
Should I plan for two chargers if the household has two cars?
If the household runs two vehicles, it is worth considering at rough-in, because running the provision for a second point while the walls are open costs far less than adding it later. Whether the supply can support two chargers at once is a separate question for the electrician.
Where can I check the current BASIX requirements?
The NSW Planning Portal publishes the BASIX framework and guidance on how it interacts with planning approvals. Check the current requirements there and against the approval for the specific job, because the rules change and what applied last year may not apply now.
Sources
- BASIX · NSW Planning Portal
- Electrical safety · Safe Work Australia
- BASIX and planning approvals · NSW Planning Portal
- Modern methods of construction · NSW Department of Planning, Housing and Infrastructure
Published 21 July 2026. General information for builders, not legal, financial or engineering advice for a specific job. Check current requirements with the relevant regulator or standard before relying on them.
