EV Charging In Strata: More Chargers Without A Power Upgrade
Electric vehicle ownership is climbing and strata buildings are feeling it first. Committees that fielded one charger request two years ago are now fielding them monthly. The instinct is to assume the building needs a bigger electrical supply, and that instinct gets expensive fast.
There is a better first step. Measure what the building actually uses, then find out how much room is already there. Plenty of Australian apartment buildings run at a fraction of their supply rating for most of the week. The question is not whether spare capacity exists. It is whether anyone has bothered to look.
Key Points
- Adding EV chargers to a strata building does not automatically require an upgrade to the electrical supply.
- The Wiring Rules allow maximum demand for an existing installation to be established by measurement or by assessment, which gives owners corporations an evidence based alternative to a conservative calculated figure.
- Assessment is the mechanism that makes load managed charging work, because a controlled charger operates on a defined duty cycle rather than as an uncontrolled addition to building load.
- EV charging drawn from the common property supply can be excluded from a NABERS Energy rating provided a kWh meter measures it, so a building without submetering risks losing stars for load that should never have counted.
- Where charging electricity is billed to residents by the kilowatt hour, a pattern approved meter installed upstream of the chargers is a recognised way to meet Australian trade measurement requirements.
- SATEC metering and the Expertpower platform provide the demand data, the live control signal and the billing measurement point that a strata charging system needs to work within the capacity a building already has.
Why EV Charging Puts Pressure On Strata Buildings
One charger is rarely a problem. Twenty is a different conversation entirely.
Apartment buildings already carry substantial electrical load. Lifts, ventilation, car park lighting, pumps, common area air conditioning and fire systems all draw from the same supply. Add uncontrolled charging on top and peak demand climbs toward the limit of the incoming connection.
The damage is usually done quietly. Chargers get approved one at a time as residents ask for them, each decision reasonable on its own. Two years later the headroom has gone and the next applicant is refused. At that point the building faces either an upgrade it never planned for or a committee argument about who was allowed to connect and who was not.
A coordinated approach avoids that outcome. It also gives the owners corporation something defensible to point at when the refusals start.
What The Wiring Rules Actually Allow
Here is the part most committees are never told.
Maximum demand for an existing installation does not have to be calculated from the standard tables. Clause 2.2.2 of the Wiring Rules sets out four methods:
- Calculation applies diversity factors from the appendix tables.
- Assessment uses engineering judgement where loads fluctuate or run on a defined duty cycle.
- Measurement records the highest sustained demand at the main board over a thirty minute period.
- Limitation caps demand at the rating of the protective device.
Calculation is the sensible default for a building that does not exist yet. It has to be conservative because there is nothing yet to observe. A building that has been running for fifteen years is in a completely different position. It has a record.
That record frequently shows a supply operating well below its rating for most of the week. The capacity is there. Nobody has measured it.
Why The Assessment Method Changes The Answer
This is where load management stops being a convenience and becomes a compliance pathway.
The Wiring Rules permit maximum demand to be assessed where equipment operates under fluctuating or intermittent loading or a defined duty cycle. A properly designed load management system gives EV charging exactly that. Charging is no longer an unpredictable addition to building load. It becomes a controlled load operating within limits a designer can demonstrate on paper.
The practical effect is significant. A building can support charging that a straight calculation would never permit, because the calculation assumes every charger runs at full current simultaneously and the assessment does not. Industry guidance for apartment complexes now favours assessment backed by limitation for precisely this reason.
Metering Shows Where The Spare Capacity Sits
Demand in an apartment building is not flat. It rises through the evening as residents come home, peaks on hot afternoons when air conditioning works hard and falls away after midnight.
Logging that profile at the main switchboard turns guesswork into engineering. Rather than asking whether the building has room, a consultant can point to the actual demand curve and identify the windows where headroom exists.
The Overnight Window Is Not As Empty As It Looks
This is where a lot of charging plans get optimistic.
Overnight looks like free capacity. Lifts are quiet, the car park is on sensors and most apartments are asleep. Plenty of older Australian buildings, though, still run controlled load hot water in exactly that window. The supply that appears idle at two in the morning may already be carrying a serious block of load.
Metering catches this. A calculation does not. It is one of the more common reasons a charging plan built on assumptions runs into trouble at commissioning.
Dynamic Load Management Turns Data Into Charging Capacity
Once the demand profile is understood the building can start controlling charging rather than simply permitting it.
Dynamic load management works from a live measurement of total building demand. When the building is busy, charging current is reduced across the connected vehicles. When demand falls, capacity is released back to the chargers. The incoming supply stays protected because the system responds to the actual figure rather than a design assumption.
For a strata property this changes the economics considerably. A supply that could accommodate four uncontrolled chargers might comfortably support fifteen or twenty controlled ones, because no vehicle needs full current for the whole night. Most cars sit connected far longer than they need to charge.
The Check Meter That Protects The Building
Load management systems fail. Timers get reprogrammed, software drops out, someone changes a setting during a service visit. A charging design that assumes the control system always works is not a design a competent consultant will sign.
The answer is a check meter at the point of supply, driving a contactor on the charging submain. It watches total building current independently of the charging system. If demand climbs toward the limit of the main breaker, it drops the charging load before the breaker ever sees the current.
This is the arrangement that lets a designer demonstrate, under the assessment method, that EV charging cannot push the building past its supply capacity. It also decides what happens when something goes wrong. Without it the building loses supply to every apartment. With it the building loses charging for an hour and nobody else notices.
Where The Real Ceiling Sits
Load management is not unlimited and it is worth being honest about that at the committee meeting rather than after installation.
Every additional vehicle reduces the share available to the others. Eventually the overnight charge becomes too small for residents who drive any distance, and the complaints begin. That threshold, not the switchboard rating, is usually the point at which a building genuinely needs more supply.
The value of good metering is that it shows you the approach to that point rather than the arrival. It also gives the owners corporation the evidence to justify the spend when the time comes.
Comparing The Options For Strata Charging Capacity
| Approach | What It Involves | Effect On Existing Capacity | Best Suited To | Main Limitation |
|---|---|---|---|---|
| First Come First Served Connections | Chargers wired individually as residents request them with no overall plan | Consumes spare capacity quickly and unpredictably | Very small buildings with one or two interested residents | Later applicants are refused because the capacity has already gone |
| Charging From Individual Apartment Meters | Each charger fed from the resident’s own meter and circuit | Leaves common property capacity untouched | Buildings where parking sits close to the apartment switchboard | Cable runs are often long and costly and the apartment supply may have little spare capacity |
| Shared Chargers With A Fixed Current Limit | Chargers on the common property supply capped at a permanent set value | Protects the main supply but wastes capacity whenever the building is quiet | Buildings adding a small number of shared visitor or resident bays | Charging stays slow at all hours even when the building is nearly idle |
| Dynamic Load Management With Metering | Charging current varied continuously in response to measured building demand, with a check meter as backstop | Uses spare capacity as it becomes available while protecting the incomer | Buildings planning for steady growth in EV ownership | Requires accurate metering, a controller and ongoing management |
| Full Electrical Supply Upgrade | New switchboard, cabling and in some cases a larger connection | Adds capacity rather than managing it | Buildings genuinely operating at their measured limit | Highest cost and longest lead time with network approval required |
Billing Residents Fairly And Lawfully
Capacity is the engineering question. Cost recovery is the one that reaches the committee meeting.
Residents without an electric vehicle should not be funding the charging of those who have one. Where charging runs off the common property supply and the cost lands in the levies, that is exactly what happens. Measurement is the only clean way to settle it.
The measurement has to be done properly though, and this is where installations get caught out. Under Australian measurement law a charger is not an electricity meter. Charging equipment sits under its own framework with its own timetable, and a great deal of hardware already installed across the country has never been assessed for billing accuracy at all. Building a cost recovery model on that measurement is a risk the owners corporation carries, not the charger vendor.
There is a cleaner route. A pattern approved meter installed upstream of the chargers is a recognised way to satisfy trade measurement requirements without depending on the charging hardware to do the job. The measurement point sits in the switchboard where it can be sealed, verified and audited. Chargers can then be chosen, replaced or upgraded over the years without disturbing the billing basis.
Buildings that bill on a basis other than energy consumed, by time connected for instance, sit outside the energy measurement rules altogether. That is a legitimate option although it tends to be unpopular with residents who charge efficiently.
There is a second layer worth raising early. Recovering electricity costs from residents can bring the owners corporation within the retail exemption framework administered by the regulator, with separate arrangements in Victoria. Where the building already operates an embedded network, the network manager or retailer may hold the meter contract and their agreement will be needed too.
The NABERS Consequence Nobody Mentions
Buildings that hold a NABERS Energy rating have a specific reason to submeter charging, and it almost never appears in the committee papers.
EV charging drawn from the common property supply does not form part of the minimum energy coverage for a NABERS Energy for Apartment Buildings rating. It can be excluded from the rating provided a kWh meter measures it and that meter is validated under the NABERS rules.
Without that meter the charging load simply lands in the building’s total consumption. The rating falls at the next assessment. A building ends up looking less efficient for supplying infrastructure that residents requested, funded and use responsibly.
One submeter on the charging distribution board prevents the entire problem. It costs a small fraction of what a lost star costs a building that markets itself on its rating.
Talk To The Network Before The Committee Votes
Adding meaningful charging load to a building is a matter for the local distribution network business, not only the electrician.
Requirements vary between networks but the pattern is consistent. Beyond a certain size the network wants to know about the load and may impose conditions on how it is controlled. In some cases a demand management arrangement becomes the condition of approval rather than an option the building can consider.
A building that arrives with measured demand data and a documented load management strategy is in a far stronger position than one arriving with a request and an estimate.
Metering For EV Charging In Strata From SATEC
SATEC has spent 50-plus years building electricity meters and energy management systems for measurement problems of exactly this shape. Australian strata charging asks three different things of a metering system, and they are rarely supplied well by a single vendor.
The first is a clear picture of total building demand at the main switchboard, logged over enough time to be representative rather than anecdotal. Meters installed at that point give the consultant what is needed to establish maximum demand by measurement or to support an assessment, and to show where the headroom genuinely sits.
The second is a live signal for the load management system. Communications outputs pass real time demand values to the charging controller so allocation responds to building conditions rather than a fixed assumption. This is also where a check meter earns its place, watching current at the point of supply and dropping the charging submain before the main breaker ever reacts.
The third is defensible measurement of the charging load itself. Where consumption is billed to residents by the kilowatt hour, NMI pattern approved metering installed upstream of the chargers provides a measurement point that meets Australian trade measurement requirements independently of the charging hardware. That same submetering keeps EV consumption visible as a separate cost centre and available for exclusion from a NABERS rating.
Expertpower brings all of it together. The platform trends demand across the building, tracks how charging load grows as more residents connect and produces the reporting an owners corporation needs when the upgrade question eventually arrives. Committees make better decisions with two years of data in front of them than with one contractor’s opinion.
Plan Before The Requests Arrive
No strata building needs a charger in every bay tomorrow. Every strata building needs a position on how charging will expand.
That position should cover measured demand, metering, load management, billing, communications and the point at which an upgrade becomes genuinely necessary. A committee with those answers can approve requests with confidence. A committee without them makes decisions in the order the requests happen to arrive, which is how buildings run out of capacity while still believing they have plenty.
The approval pathway may also be easier than committees expect. In New South Wales EV charging is treated as sustainability infrastructure, which means the resolution passes unless fifty per cent or more of the value of votes cast are against it. That replaced the seventy five per cent special resolution that used to apply. Other states take different approaches, so confirm the position that applies to your scheme before drafting the motion.
Make Existing Capacity Work Harder
EV charging in strata does not automatically mean a major power upgrade.
For most buildings the first step is to measure existing demand and find out how much capacity is already available. Load management then makes better use of that capacity by adjusting charging to real electrical conditions, and a check meter makes the arrangement safe enough to sign.
Accurate metering supports every part of the process. It establishes the demand figure, feeds the control system, measures consumption for billing and protects the building’s energy rating. Start there. It is the cheapest step and it changes every conversation that follows.
Talk to SATEC about metering for EV charging in your building. Contact our team for advice on measuring building demand, supporting dynamic load management and metering charging loads for accurate cost recovery.
FAQs - EV Charging In Strata
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Do we need to upgrade the building's electrical supply before installing EV chargers?
Not necessarily. Many buildings have unused capacity that only becomes visible once demand is measured at the main switchboard. Measurement should always come before an upgrade decision because it frequently changes the answer.
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Can EV charging electricity be billed to individual residents?
Yes, and the cleanest method is a pattern approved meter installed upstream of the chargers rather than relying on the charging hardware to perform the measurement. Chargers sit under a separate and still transitioning framework under Australian measurement law. The owners corporation should also check its position under the retail exemption framework before charging residents for consumption.
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Will EV charging affect our building's NABERS rating?
It will if the charging load is not separately metered, because it lands in the building's total consumption. Charging drawn from the common property supply can be excluded from the rating provided a kWh meter measures it and that meter is validated under the NABERS rules. A single submeter on the charging board resolves it.
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Do we need approval from the electricity network before adding chargers?
Usually yes, once the load reaches a meaningful size. Distributors publish their own requirements for EV charging connections and may require the load to be controlled as a condition of approval. Arriving with measured demand data and a documented load management strategy makes the process considerably smoother.
