This part of GSO IEC 61557 specifies the general requirements for measuring and monitoring equipment for testing the electrical safety in low voltage distribution systems with nominal voltages up to 1 000 V a.c. and 1 500 V d.c. When measuring equipment or measuring installations involve measurement tasks of various measuring equipment covered by this series of standards, then the part of this series of standards relevant to each of the measurement tasks is applicable. NOTE The term "measuring equipment" will hereafter be used to designate "testing, measuring and monitoring equipment".