For example, it has been found that a single switch 5 can interrupt a current at a voltage of approximately 208 volts while a unit composed of the two switches 5 and 7, interconnected in series, can interrupt a current at a voltage of approximately 350 volts.74 Furthermore, by the use of two current responsive latch elements 17, the resistance of the switch unit thus provided is doubled and the switch acts more efficiently as a current limiter and, furthermore, by employing two housings of electrically nonconductive material, arcing problems between the adjacent sets of contacts are eliminated, which problem might occur if all of the contacts were in a single housing.