This standard BS G 194:1965 Specification for lever-operated manual switches for aircraft is classified in these ICS categories:
49.060 Aerospace electric equipment and systems
This British Standard specifies the requirements for two classes of single-hole fixing, lever-operated manual switches for use in nominal 28 volt d.c. and 115/200 volt three-phase, 400 cycle a.c. systems in aircraft.
Class 1 switches are sealed and are suitable for higher altitude and wider temperature conditions than Class 2, which are sealed only at the lever entry.