Do I need a consumer unit upgrade for an EV charger?

An EV charge point is a dedicated circuit with specific protection requirements, set out in Section 722 of the wiring regulations. There are three things the board has to be able to provide.

1. A spare way, physically, for the protective device.
2. The right kind of RCD protection, either a Type B RCD, or a Type A combined with a 6mA DC fault detection device. Ordinary Type AC RCDs are not suitable, because EV charging can produce smooth DC residual current that would stop them working.
3. Protection against an open PEN conductor, on the majority of UK supplies which are PME. Most current charge points have this built in; where they don't, an earth electrode is the alternative.

That second point is the one that catches out older boards. A board full of Type AC RCDs is not automatically a problem for the charger circuit, because the DC detection commonly sits inside the charge point itself, but it does need checking rather than assuming.

1. It goes straight in

Your board has room, it's in good condition, and it can take the device required. Nothing else needed. This is a genuinely common outcome on boards fitted in the last decade or so.

2. A separate enclosure alongside

The board is sound but full, or it's a type that can't take the right device. A small enclosure is fitted next to it, fed from the supply side, containing the charger's own protection. Cheaper than a full upgrade, and perfectly proper, but it does mean two boards on the wall.

3. A consumer unit upgrade

The board is a rewireable fuse board, or a plastic unit in a position that now calls for a metal one, or it's showing heat damage. Then the upgrade is worth doing on its own merits and the charger is a good excuse to get on with it, and you save a second set of testing by doing both at once.

Separate from the board is the incoming main fuse. Many UK houses have 60A, 80A or 100A. A 7.4kW charger draws 32A continuously for hours.

Add an electric shower at 40A and an induction hob, and a 60A supply can be asked for more than it can give. The answer is almost never a supply upgrade, because that's a job for the network operator with cost and lead time attached. It's load management: a current transformer clamped around the incoming tails tells the charger to back off when the rest of the house is busy, then let it back up again.

In practice you barely notice. The car is charging overnight when nothing else is on, and the throttling only happens at the moments you're cooking and showering at once.

You can get most of the way there yourself with two photographs: one of the consumer unit with the cover on, and one of the meter and main fuse. Between them, an installer can normally tell you which of the three outcomes above applies to you and roughly what it means.