In short: a lot of Perth switchboards can't take solar, a battery or an EV charger without an upgrade first. The board either has no spare space, no safety switch protection, or a main switch that's already near its limit. Getting the switchboard sorted first avoids paying twice, and if you're planning an EV charger and big air conditioning, it's worth asking about three phase at the same time.
If you're getting quotes for solar, a home battery or an EV charger, the switchboard is the part of the job most people don't think about until the installer turns up and says "we can't connect to that."
Why these three jobs stress an old switchboard
Each of them needs a dedicated circuit at the switchboard, and each draws serious current:
- Solar needs its own main switch and protection for the inverter, and it feeds power back into the board rather than just drawing from it.
- A battery adds another circuit and, if it's set up for backup, changes how the main switch and critical circuits are wired.
- An EV charger is often the single biggest load in the house. A 7 kW charger can draw 32 amps continuously for hours, more than an oven and cooktop together.
A board built in the 1970s or 80s, with a handful of circuits and a 63 amp single phase supply, was never designed for any of that.
Signs your switchboard won't cope
- No spare space. Open the board and look. If every position is used, there's nowhere to put the new circuit.
- Ceramic fuses or no safety switches. Any new circuit has to have RCD protection, and if the board is that old, the installer will usually require it to be replaced before they'll connect.
- The main switch is already working hard. If the safety switch or main breaker trips when the air conditioning and oven run together, adding an EV charger makes that a daily event.
- Single phase and you want a fast charger. A 22 kW charger needs three phase. So does some ducted air conditioning and most pool heat pumps.
If you're not sure, send us a photo of the open board. That's usually enough to tell you whether it's fine, needs a couple of additions, or needs replacing.
When three phase is worth it
Most Perth homes are single phase. Three phase brings in three supply lines instead of one, so the house can draw a lot more power at once without tripping.
It makes sense if you're planning two or more of these: an EV charger, a large split system or ducted air conditioning, a pool heat pump, an induction cooktop, or a big solar and battery system. It doesn't make sense for a small home that just wants a 7 kW charger, because a single phase board in good condition handles that fine.
Three phase involves an application to Western Power to upgrade the supply, and the switchboard has to be rebuilt to suit. It's a bigger job, but doing it once while the board is being replaced anyway is far cheaper than doing it later.
The right order to do things
- Get the switchboard assessed first, before you sign with a solar or charger installer. Every booked job with us includes a free switchboard inspection.
- If it needs an upgrade, do that as the first job. Our Switchboard Upgrade Perth page covers what's included, and we've broken down what a switchboard upgrade costs in Perth.
- Have the EV charger circuit run at the same time, even if the charger itself comes later. Running the cable while the board is open is cheaper than a second visit. See our EV Charger Installation Perth page and the guide to EV charger installation cost in Perth.
- Then solar and battery. The solar installer will thank you for it.
Nexus Electrical Co | Switchboard Upgrade Perth
Nexus Electrical Co is a licensed and insured electrician Perth homeowners have trusted for 6000+ jobs, based in Balcatta. We hold both electrical and refrigerant licences, so switchboards, EV chargers and split systems are all done by the same team. Fixed price before we start, 100+ Google 5-star reviews. Call (08) 9245 1362.
