The standard lead length for most tethered chargers is just over 5.5m. This is normally sufficient to reach the car from the charge point without having to awkwardly manoeuvre the charging cable. Remember that you’ll want the cable to run along the ground so remember to include some slack for that if you’re measuring.
Some models can be ordered with longer tethered leads if the car is going to be parked further away from the charge point. The Anderson A2 and the Rolec WallPod:EV HomeSmart are both available with a 10m long tethered lead.