Applies to three-pole units for public and industrial distribution systems assemblies of switches and current-limiting fuses which interrupt, any load current up to the rated breaking current of the switch and any over-current up to the rated short-circuit breaking current of the combination by which automatic interruption is initiated. Does not apply to fuse-circuit-breakers, fuse-contactors, combinations for motor-circuits or to combinations incorporating single capacitor bank switches. Covers normal and special service conditions, definitions, design and construction, type tests, routine tests, application guide for the selection of switch-fuse combinations for service and information to be given with enquiries, tenders and orders.