Load management explained: big appliances on one supply

Every home has a limit on how much current it can draw at once, set by the consumer mains, the main switch and the network connection. Most of the day the house uses a fraction of it. The pinch comes when several big loads overlap: oven on, heating running, hot water heating, dryer going and the car plugged in.

Load management is a way of sharing that limit. A current sensor measures what the whole house is drawing at the incoming supply. When the total approaches a set ceiling, a controlled device, most often an EV charger, turns its own demand down or pauses. As other loads drop away, it ramps back up.

The car still charges fully overnight. It just doesn't charge at full rate during the hour you're cooking dinner. On a modest supply, that can be what makes a wall charger workable without touching the connection.

The sensor is usually a clamp around the incoming cable at the switchboard or meter box, linked by cable or wirelessly to the charger or controller. Because it sits beside the main conductors, fitting it is part of the licensed electrical work.

The ceiling is a setting, chosen from the main switch rating, the mains and how the house runs. Set it too high and the main switch can still trip on a busy evening. Set it too low and the car charges slowly for no reason. Getting it right is part of commissioning, not a factory default left in place.

Ask what happens when the sensor reading is lost, such as a Wi-Fi dropout or a failed link. A well-designed setup falls back to a low rate or pauses, rather than charging at full power with no idea what the house is doing.

The best candidates are loads that store energy or can wait. EV charging is the obvious one. Hot water that heats a tank can often be moved to a timer or off-peak period, and pool or spa equipment can usually run later. Some chargers can also follow your solar, using power the house isn't.

Loads that need to run when you switch them on make poor candidates. Nobody wants the cooktop throttled mid-stir-fry or the heating cut on a still July night. Those loads stay as they are, and the managed loads fit around them.

Load management, a heavier single-phase supply and three-phase all solve the same problem from different ends. Load management changes when power is used. A consumer mains upgrade raises the limit on one phase. Three-phase spreads the house across three phases and suits large loads that run together.

If one flexible load, usually the car, is what tips the house over, load management is often the neatest answer. If the main switch trips with nothing flexible running, or you're adding several big loads at once, the supply is the issue. Three-phase makes sense for a large ducted system, two EV chargers or a higher-rate charger, a workshop with three-phase machines, or an all-electric home where heating, cooking and hot water overlap in the evening.

Consumer mains, meter box and main switchboard work is prescribed in Victoria, so a Licensed Electrical Inspector checks it before it can be switched on, and any change to the connection goes through your distributor. Load management avoids that process, which is part of its appeal, but only when it genuinely covers the shortfall.

Under Victoria's Building and Plumbing Amendment Regulations 2025, all new homes must be built all-electric from 1 January 2027, and from 1 March 2027 gas hot water in existing homes must be replaced with an electric alternative when it reaches the end of its life. Each change moves another load onto the switchboard.

The tightest hour in most homes in Melbourne's west is a winter weeknight. July is the coldest month at Laverton, with a mean minimum of 5.2 °C, and that's when heating, cooking, hot water and a car plugged in after work all pull at once. Load management is built for exactly that overlap: the car waits an hour, and the house carries on.

Older post-war homes can have small mains and an original board, so the limit arrives sooner. Newer homes in growth estates tend to have more headroom, but a second EV or a larger ducted system can still use it up.

Start with the numbers: the main switch rating, the mains size and a picture of what runs together on your busiest evening. Interval data from your smart meter, if your retailer or distributor provides it, can show the peaks. From there we set the ceiling, place the sensor and test it with real loads running, not just the car.

Revisit the settings after any change to the house. A new split system, induction cooktop or hot water unit shifts the evening peak, and a ceiling set two years ago may no longer fit.