A transformer switch, such as a dual voltage switch or a tap changer. The switch includes a cover, a housing, and a rotor sandwiched between the cover and the housing. The cover and housing are molded from a non-conductive plastic. An interior space of the cover includes at least one pocket within which stationary contacts are disposed. Each stationary contact is electrically coupled to one or more windings of a transformer. The rotor extends within a channel of the housing, from a top of the transformer switch to an interior surface of the cover. The interior surface includes a protrusion about which the rotor and at least one movable contact coupled thereto can rotate. The movable contact is configured to be selectively electrically coupled to at least one of the stationary contacts. For example, different stationary contact-movable contact pairs can correspond to different voltages of the transformer.