Key takeaways
- An all-electric home replaces gas loads with electrical loads that often peak at the same time, so maximum demand planning is a design task, not a rough guess at rough-in.
- BASIX is a condition of the development consent on many NSW residential projects, so electrical capacity for the nominated appliances needs to be resolved before the certifier signs off.
- The switchboard is the point where diversity, circuit allocation and future capacity are fixed, and changes after the board is built and the meter is relocated carry real cost.
- Load management devices can defer or shed large loads so the consumer mains and board rating suit the actual peak, but they must be documented and commissioned so the owner and the next electrician can work with them.
- SafeWork Australia’s electrical safety guidance applies to any work near live parts, and on an all-electric site the builder needs to control who is on the board and when.
An all-electric home is not simply a house with a different appliance schedule. It is a house where the entire thermal and transport load — cooking, hot water, space heating, cooling and vehicle charging — lands on one switchboard and one supply. On a gas-connected project, those loads were spread across two energy sources. On an all-electric project, they are not.
The consequence is that maximum demand stops being a formality on the electrical plan and becomes a design constraint. The switchboard is where that constraint is resolved. Circuit allocation, spare capacity, diversity assumptions and any load control device all live on or beside the board, and they are all difficult to change once the board is built, the meter is relocated and the owner has moved in.
This article is about the switchboard and circuit-level side of electrification. It does not cover appliance selection or the case for going all-electric in the first place. It assumes the decision has been made and the question now is how to make the electrical installation carry it.
Load planning stages across an all-electric build
- 1Design and appliance scheduleThe designer lists every fixed electrical load, including cooking, hot water, heating, cooling and vehicle charging.
- 2Maximum demand assessmentThe electrician applies diversity and decides whether the consumer mains and board rating are adequate.
- 3Load management strategyWhere the calculated peak exceeds supply, a control device or interlock is selected and documented.
- 4Switchboard layout and circuitsFinal circuit allocations, spare ways and labelling are set out before the board is built.
- 5Rough-in and installationCables, isolators and control wiring are installed to the agreed layout, with the board kept closed to other trades.
- 6Commissioning and handoverThe load control settings are verified and the owner receives an explanation of what will shed and when.
Why an all-electric home changes the load calculation
In a mixed-fuel home, the electrical maximum demand is dominated by a handful of loads and the gas appliances sit outside the calculation entirely. Once gas is removed, those loads move onto the electrical side and, importantly, they tend to overlap. A winter evening can have the heat pump hot water recovering, the reverse-cycle system heating, the induction cooktop running and the vehicle charging, all within the same hour.
Diversity is the tool electricians use to avoid designing for the worst-case simultaneous peak. It is a legitimate approach and it is embedded in the way maximum demand has always been assessed. The problem with an all-electric home is that the diversity assumptions that suited a gas-connected house may not suit the new load profile. Hot water and space heating, which used to be gas, now compete for the same supply at the same time as cooking and charging.
This is the point where the builder’s design coordination matters. If the appliance schedule is finalised late, or if the owner upgrades to a larger cooktop or a second vehicle charger after contract, the electrical design that was priced may no longer be adequate. The cost of discovering that at fit-off is not just the extra cable and a larger board. It is the possible need to revisit the supply capacity with the network, which is a slow and expensive process.
What BASIX requires and how it interacts with the electrical design
BASIX is the NSW sustainability index that applies to many residential developments, and it is administered through the NSW Planning Portal. It is not an electrical standard, but it has a direct effect on the electrical design because the commitments made in the BASIX certificate become conditions of the development consent. If the certificate nominates a particular hot water system, heating type or ventilation approach, those commitments need to be delivered in the built home.
The practical risk is a mismatch between what was nominated and what is installed. An electrician who has not seen the BASIX commitments may rough in for a different hot water arrangement. A builder who changes the heating specification mid-build to suit availability may breach the consent without realising it. The electrical design should start from the same appliance schedule that underpins the certificate, and any change to that schedule should be checked against the certificate before it is ordered.
The BASIX and planning approvals guidance on the NSW Planning Portal sets out how the certificate sits within the approval process. For a builder, the takeaway is that the electrical load plan and the BASIX commitments are two views of the same appliance schedule. They should be reconciled before rough-in, not after.
Switchboard capacity: the decision that is hardest to reverse
The switchboard is the most expensive thing to change late. Consumer mains, the main switch, the board enclosure and the meter position are all set early, often before the frame is complete. If the calculated maximum demand later turns out to exceed what the board and mains were sized for, the options are limited: upgrade the supply, or manage the load.
Spare capacity is the cheapest insurance available at design stage. Leaving spare ways costs a little now and avoids a board replacement later. The same applies to the physical size of the enclosure and the position of the board, which should allow for additional devices, a load control unit or a future battery connection without a major rebuild.
The board also needs to be controllable. On a busy all-electric site, multiple trades may want to isolate circuits for their own work. SafeWork Australia’s electrical safety guidance makes clear that electrical risk must be managed, and an open, unlabelled board with live parts exposed is exactly the kind of hazard that guidance is aimed at. A lockable board, clear labelling and a rule about who opens it are practical controls that cost almost nothing.
Switchboard checks before the board is built
- Confirm the appliance schedule matches what was nominated to the certifier for BASIX purposes.
- Check that the consumer mains and main switch rating suit the calculated maximum demand, not the old gas-era assumption.
- Allow spare ways for future loads such as a second vehicle charger or a battery.
- Confirm where the load control device sits in the circuit hierarchy and how it is labelled.
- Check that isolators for fixed appliances are accessible and identified.
- Confirm the board is lockable or otherwise controlled so other trades cannot open it.
- Record the final settings and circuit schedule for the owner and the next electrician.
Lead in. The mistake that costs the most is committing to a switchboard and consumer mains based on a gas-era load assumption, then discovering at commissioning that the all-electric appliance schedule exceeds it. By then the board is built, the meter is set and the only remaining options are an expensive supply upgrade or a load management retrofit that should have been designed in from the start.
Circuit-level planning: allocation, isolation and control
Circuit allocation is where the load plan becomes physical. Each fixed appliance needs its own final circuit, its own protection and, where required, its own isolator. On an all-electric home, that list is longer than on a mixed-fuel home because the cooking, hot water and heating loads are all electrical.
The allocation should follow the way the house will actually be used. Cooking, hot water and space heating are the loads most likely to run concurrently on a winter evening, and the vehicle charger is the load most likely to be added or upgraded later. Grouping them thoughtfully across circuits and phases, where a three-phase supply is available, gives the electrician more options for balancing the load and reduces the chance that a single circuit carries more than it should.
Labelling matters more on an all-electric board than on a mixed-fuel one. The owner will interact with the board when a circuit trips, and a future electrician will rely on the schedule when adding a load. A board that is labelled to the final circuit schedule, with the load control device identified and its function explained, is a board that can be maintained. A board that is not is a source of callbacks.
The related articles on EV charger rough-in for residential builds, induction cooktop electrical requirements and split system air conditioner installation in NSW cover the appliance end of these circuits. The switchboard is where they all meet.
Load management devices: what they do and what they need
A load management device monitors the total draw at the supply and either sheds or defers a controlled load when the total approaches a set limit. In practice, the controlled load is usually the vehicle charger, because it is the largest single load and the one whose timing is least critical. Some devices can also cycle hot water or limit heating, depending on how they are configured.
The important point for a builder is that a load management device is a design decision, not an accessory. It changes the circuit hierarchy, it needs a place on or near the board, it needs to be commissioned with settings that suit the household, and it needs to be documented so the owner understands what will happen when they plug in the car while the oven is on.
There is also a handover obligation. An owner who does not know that the charger will reduce its rate when the cooktop is running may report it as a fault. A short explanation at handover, plus a written note of the settings, prevents that call. It also gives the next electrician something to work from, which matters because load control settings are often adjusted as a household’s needs change.
Two ways to keep an all-electric home within supply
| Upgrade supply capacity | Manage the load |
|---|---|
| Higher consumer mains and board rating | Existing supply retained with a control device |
| Cost sits in the network connection and board | Cost sits in the control device and commissioning |
| No behaviour change for the occupant | Some loads shed or defer automatically |
| Future loads still need checking | Future loads may need re-tuning the control settings |
| Simple to explain at handover | Requires clear documentation to be understood later |
Coordination with other trades and the certifier
The switchboard is a coordination point. The electrician needs the final appliance schedule, the position of the meter, the location of the vehicle charger and the heating and cooling equipment, and the owner’s intentions for future loads. The builder is usually the one holding that information, and the earlier it is shared, the fewer assumptions the electrician has to make.
Where a load management device is used, the certifier may want to understand how the installation meets the consent conditions. That is easier if the design is documented: the appliance schedule, the maximum demand assessment, the load control strategy and the final circuit schedule. A file that shows the reasoning is more useful than a verbal explanation on the day of inspection.
Flood risk is also relevant to board location in some areas. The NSW flood risk management manual deals with development in flood-affected land, and where a switchboard is located in a flood-prone position, the design needs to account for the risk of inundation. This is a siting question that should be resolved with the certifier and the electrical designer early, because moving a board later is not a trivial change.
Worked example: a builder in western Sydney
A builder in western Sydney is delivering a detached home on a compact lot. The client has specified an all-electric home: induction cooking, a heat pump hot water system, reverse-cycle heating and cooling, and a single vehicle charger. The vehicle charger was added as a variation after the electrical rough-in was priced.
The original electrical design assumed a gas cooktop and gas hot water, with the electrical load dominated by the reverse-cycle system and general power. The switchboard was sized accordingly, with limited spare ways and no provision for a load control device. When the variation came through, the electrician recalculated the maximum demand and found that the winter evening peak — hot water recovery, heating, cooking and vehicle charging — was well above the original assumption.
The options were an upgrade to the consumer mains and board, which would have meant revisiting the supply with the network, or a load management device that limited the vehicle charger when the total draw approached the supply limit. The builder chose the load control route because it was faster and cheaper, but it required a new board with space for the device, a revised circuit schedule and a commissioning step at handover.
The lesson is not that load management is the wrong answer. It is that the decision was made late, after the board had been ordered, and the cost and disruption reflected that. Had the vehicle charger been in the appliance schedule at design stage, the same outcome could have been achieved with a board that was already sized and laid out for it.
Handover, documentation and the next electrician
An all-electric home hands over with more electrical complexity than a mixed-fuel home, and the owner is likely to interact with it. The handover pack should include the final circuit schedule, the load control settings and a plain-language explanation of what the system will do under load. That is not a technical manual; it is a page or two that answers the question the owner will actually ask.
The same documentation serves the next electrician who works on the house. Load control settings are often tuned over time, and a record of what was set and why saves the next person from guessing. It also reduces the risk that a future addition, such as a second vehicle charger or a battery, is installed without checking whether the supply and the control strategy can carry it.
For builders, the broader point is that electrification moves electrical design earlier in the programme. The appliance schedule, the BASIX commitments and the switchboard design need to be aligned before rough-in. Builders who treat that as a design task rather than a site task spend less time fixing electrical problems at fit-off. The PointCPD guide to how NSW builder CPD works explains how this kind of technical content fits into the continuing professional development framework, and the PointCPD course catalogue lists the courses that cover it in more depth. Builders looking for the full set of NSW builder CPD courses can start at the PointCPD home page.
Questions builders ask
Does an all-electric home always need a load management device?
No. If the calculated maximum demand fits within the supply and the consumer mains, no control device is needed. A load management device is one way to keep an all-electric home within an existing supply when the peak would otherwise exceed it. The decision should come out of the maximum demand assessment, not be assumed at the start.
When should the switchboard design be finalised on an all-electric project?
Before rough-in, and preferably before the board is ordered. The switchboard depends on the appliance schedule, the BASIX commitments and the position of the meter, all of which are usually settled early. Changes after the board is built are expensive because they can affect the consumer mains, the supply capacity and the enclosure itself.
How does BASIX affect the electrical design of a new home?
BASIX commitments become conditions of the development consent, so the appliances nominated in the certificate need to be the appliances installed. That means the electrical design should start from the same appliance schedule that underpins the certificate. If the schedule changes mid-build, the certificate should be checked before the change is ordered.
Can a second vehicle charger be added later without upgrading the switchboard?
Possibly, but it depends on the spare capacity left in the board and the headroom in the supply. Leaving spare ways and documenting the load control strategy at handover makes a later addition more straightforward. Adding a second charger without checking the supply and the control settings is how overloads and nuisance tripping start.
What should be in the handover pack for an all-electric home?
At minimum, the final circuit schedule, the load control settings if a device is installed, and a plain-language explanation of what will shed or defer under load. The owner needs to know why the vehicle charger may slow down when the oven is on, and the next electrician needs a record of the settings to work from.
Does flood risk affect where the switchboard can be located?
It can. The NSW flood risk management manual deals with development on flood-affected land, and a switchboard in a flood-prone position needs to account for the risk of inundation. This is a siting question that should be resolved with the certifier and the electrical designer early, because relocating a board later is disruptive.
Sources
- BASIX · NSW Planning Portal
- Electrical safety · Safe Work Australia
- BASIX and planning approvals · NSW Planning Portal
- Flood risk management manual · NSW Government
Published 30 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.
