Abstract: A trigger operated switch assembly for a portable hand tool such as an electric drill that includes a switch casing, housing a switch contact module and a reciprocally movable contact carrier operatively engageable with the switch contact module for controlling communication of electrical energy from a source to an electrical load. An elongated arm extends through an opening in the switch casing and operatively interconnects the movable switch contact module with trigger structure. A seal arrangement prevents or substantially inhibits the entry of foreign material into the switch casing and includes a seal located in wiping relation with the elongated arm and mounted within an opening integrally molded in the switch casing. An additional seal seals a gap between the switch contact module and an inside surface of the casing. An elastomeric cap covers an end opening of the casing and includes apertures through which electrical conductors extend and are connected with the switch contact module.