This standard describes certain electrical@ dimensional@ and mechanical characteristics and takes into consideration certain safety features of three-phase@ 60 Hz@ low-voltage (600 V and below) network protectors. They are used for automatically connecting and disconnecting a network transformer from a secondary spot or grid network.PurposeThis standard is intended for use as a basis for establishing the performance@ electrical and mechanical interchangeability@ and safety of the equipment covered and to assist in the proper selection of such equipment.