The EV charger that started with the switchboard

The enquiry came in on a Sunday morning. He had already bought the charger. The car had not arrived yet.

That last detail is the reason this job went well, and it is the opposite of how most EV charger jobs reach us. Usually the car is in the driveway, the charger is in a box in the hallway, and everyone wants it working by the weekend. This homeowner got in touch before the vehicle was delivered, which gave us room to look properly at what his house could actually carry.

The assessment came first

We booked a paid EV pre-install assessment for the Tuesday. It is a fixed price and it covers earth continuity testing, a full switchboard and circuit protection inspection, a maximum demand assessment of the electrical supply, charger location and cable route planning, and a written photographic report with a clear recommendation, delivered the same day. If the installation goes ahead with us, the whole fee is credited against it. On this job it was, and the invoice shows it at zero.

We were on site an hour and twenty minutes. Here is what Michael said on camera while he was there:

We came to do an EV charger pre-site inspection, just to check out their switchboard, check the demand of their house, to see if they can actually get an EV charger installed. While we were here we noticed the switchboard didn’t have a lot of electrocution protection devices on half the house.

Michael, on site at Hoxton Park

That is the finding that shaped the job. Half the circuits in a 1995 brick veneer home had no residual current protection at all. Adding a dedicated high-draw circuit to a board in that condition is the wrong order of work.

What the board was already carrying

This was not a quiet switchboard. Air conditioning circuits, cooktops, a solar inverter and a battery, all live on the same board. Maximum demand was already high before anyone added a car to it.

That mattered for the charger choice too. We went with a myenergi Zappi, and the reason is load management. The Zappi reads the load coming into the house and trims its own draw as required, so when the air conditioners and the cooktop are all going at once, the main switch does not trip. Because the home has solar and a battery, we also supplied and installed myenergi CT clamps, rated 100A 16mm, so the charger can see what the solar and battery are actually contributing.

The work

Two days after the assessment we came back and did the lot in one visit, on site from 7.43am to 12.34pm:

• Switchboard internals replaced including the main switch, 18 pole, with individual safety switches. Old equipment disconnected, removed and disposed of, cables stripped, terminated, loomed and tidied, then tested and commissioned.
• Surge protection installed into the switchboard enclosure.
• An RCBO installed in the enclosure.
• A single phase EV charger mounted and commissioned, with its own circuit breaker, cabling, isolators and clips.
• 10mm two core and earth run to the charger, plus 4mm twin and earth for a weatherproof power point.
• myenergi CT clamps supplied and installed.

Cable selection on the charger circuit was done against AS/NZS 3008.1.1:2017. For most homes the maximum allowable voltage drop is 5% from the switchboard to the last outlet, and getting the cable size wrong on a long run to a garage or carport is one of the more common ways an EV charger install goes quietly bad. A Certificate of Compliance for Electrical Work was lodged the same day.

The part worth knowing before you buy a charger

On this job the switchboard work cost more than the charger installation did. That is not unusual. Three of our last five EV charger jobs needed the board upgraded before the charger could go on, and on every one of them the board was the larger half of the bill.

People understandably shop for chargers. The charger is the least interesting part of the price. What actually decides what an EV charger costs at your place is whether the board has capacity, whether your supply is single or three phase, how far the cable has to run, and whether load management can do the job instead of a supply upgrade.

And if you are on single phase, you can still charge. Michael gets asked this constantly:

People ask us, can I actually get an EV charger installed on a single phase home? And the answer is yes, yes you can. It may require some sort of load management. The only difference is the charging speed. With single phase you’re limited to around 7kW to charge, but that’s more than enough to charge your car overnight.

Michael, Hoxton Park

Thinking about a charger in Hoxton Park or nearby? Start with the EV charger page, or see what else we do as your electrician in Hoxton Park. If your board has ceramic fuses or missing safety switches, the switchboard upgrade page explains what a proper upgrade involves.