Gives the requirements for two classes of single-hole fixing switches for use in nominal 28 V d. c. and 115/200 V three-phase, 400 Hz a.c. systems. Class 1 switches are sealed and are suitable for higher altitude and temperature conditions than are Class 2 switches, which are sealed only at the lever entry. Furthermore, gives requirements for dimensions, operation, construction, voltage and current ratings, environment, tests, type tests, production tests, quality tests, declarations and marking.