Why This Matters to You
Most writing about home EV charging assumes a house with a garage and a switchboard on the other side of the wall. Plenty of people in Adelaide don't have that. They have a park in a shared basement, a board somewhere else entirely, and a body corporate.
This install was on the lower level of a multi-level residential car park in Greenwith. A customer-supplied EV Switch unit, 7 kW, on a new dedicated circuit. The electrical principles are the same as a house. Almost everything around them is different.
Why It Gets Its Own Circuit
A 7 kW single-phase charger draws around 32 amps, and the thing that makes an EV different to every other appliance you own is duration. A kettle pulls hard for two minutes. An oven cycles on and off. A car charger sits at close to its maximum continuously for hours.
That's why it goes on a dedicated circuit sized for continuous load rather than sharing with anything else. A circuit that copes fine with intermittent use can run hot when something sits on it all night, and heat is what degrades cable and connections over years rather than minutes. It's also why plugging a car into an ordinary powerpoint on an extension lead is a genuinely bad idea rather than just a slow one.
The Protection isn't the Same as a Powerpoint
An electric vehicle can introduce DC fault current into the supply, and an ordinary safety switch isn't built to detect that. If DC blinds the safety switch, the protection you assumed you had isn't there.
So an EV circuit needs protection that accounts for it. Some chargers have that detection built into the unit, and where they don't, it has to be provided on the circuit instead. Either way it isn't optional and it isn't something a standard powerpoint arrangement gives you. It's worth asking whoever quotes you how the DC side is being handled, because the answer tells you quickly whether they install these regularly.
The unit also has local isolation beside it, so it can be switched off where it sits rather than by walking to a board somewhere else in the building.
What's Different in a Shared Building
This is the part that catches people out, and none of it's electrical.
Whose supply is it coming from. In a shared building the answer needs to be your own meter, not common property, unless there's an agreed arrangement for metering and paying for it. Getting this wrong means you're charging your car on everybody else's bill, which tends to get noticed.
Permission. Running a new circuit through common areas and mounting equipment on a common wall isn't yours to decide alone. That's a body corporate or strata conversation, and it's far easier before the work than after.
Cable route. A car park has no wall cavities to hide anything in. The supply runs in surface conduit, which means the route has to be planned so it's neat, protected from vehicle damage, and doesn't cut across somebody else's space.
What happens when the neighbours want one. Buildings are steadily going from nobody charging to several residents charging, and the building's supply is finite. If you're first, you're in the best position. It's still worth asking what capacity is there, because the answer affects everyone who comes after you.
If You're Getting a Charger
Sort the charger choice and the location before you book the electrical, because both change the job. We install customer-supplied units like this one and we can supply a range of brands, so if you haven't bought yet that's worth a conversation first rather than after.
In a house, the questions are board capacity and the distance from the board. In an apartment, add metering and permissions to that list and start earlier. There's more on our EV charger installation page, and on what we cover locally on our Greenwith electrician page.
