A switch includes a power in contact, a piston, a power out contact, a plurality of flexible locking elements, an earthing contact, and a threaded rod. In a first position, the piston contacts the power in contact and the power out contact. In a second position, the piston contacts the power out contact. In a third position, the piston contacts the earthing contact and the power out contact. The piston comprises an inner threaded section that engages the threaded rod. Rotation of the threaded rod moves the piston along an axis of the switch between the different switch positions. The piston comprises a groove extending in a direction parallel to the axis. Each of the flexible locking elements is configured such that a part of each of the flexible locking elements moves into and out of the groove as the piston is moved along the axis of the switch.