A motor vehicle has a body with an opening that can be closed by a preferably pivotable cover and a box-shaped metallic reflector that is open towards the opening for receiving an HPEM source and that is reversibly insertable into the opening. The reflector is connected to the body by an earth connection following insertion of the reflector. The earth connection is implemented by a brush strip containing fibers of a conductive material that connects the box-shaped reflector to the body circumferentially on all sides in the region of the opening.