looks good to me, i would be tempted to make this into although it a large extension lead adaptor, depending of what you are plugging it into 13A or 16A make an adaptor.
Car charge points should not be connected to and electrical point thats is connected to a PME (TN-C-S) earthing system, which most houses (not all) are connected to. That is why if you buy a charge point, pod point, rolec etc a lot of them have the equipment built in to stop this and other...