7kW charger on a board with no room left

A new car was arriving in eleven days. The dealer had passed on a charger quote that started with the word 'from', and the owner wanted to know what the real number was before the car turned up and became a problem.

The parking spot was on the opposite side of the house from the switchboard, with a paved side path in between. That was the part the owner already suspected would cost money. It was not the part that did.

The board was a 2004 unit, full. Every way occupied, no room for another breaker, and no space in the enclosure to extend it neatly. Landing a 32-amp continuous load anywhere on it was not going to happen compliantly.

The supply itself was fine — 63 amp single phase with plenty of headroom for another 32-amp circuit once the aircon and the oven were accounted for. So this was a board problem, not a supply problem, which is a considerably cheaper problem to have.

We quoted a matched extension enclosure beside the existing board rather than a full replacement, which kept the cost down and left four spare ways for whatever comes next.

• Load assessment on the existing supply, written up before anything was ordered
• Matched extension enclosure fitted alongside the existing board, four spare ways left
• 24 metre run: surface conduit through the roof space, then buried in conduit under the side path
• 7kW wall charger mounted at the parking spot, positioned for a driver's-side port
• Dedicated RCBO with type B residual current protection as the charger requires
• Charger paired to the inverter for excess-solar charging, plus an off-peak fallback schedule

The car arrived eight days later to a charger that was already commissioned and tested, on a circuit sized for continuous load rather than for the minimum that would pass.

The load assessment is the part worth repeating. Ninety minutes on site before anything was ordered turned a potential board replacement into a board extension, and the owner knew the real figure a week and a half before the car did.