This part of IEC 62586 specifies product and performance requirements for instruments whose functions include measuring, recording and possibly monitoring power quality parameters in power supply systems, and whose measuring methods (class A or class S) are defined in IEC 61000-4-30. These requirements are applicable in single, dual- (split phase) and 3-phase a.c. power supply systems at 50 Hz or 60 Hz. These instruments can be used: – in the generation, transmission and distribution of electricity, for example inside a power station, substation or a distributed generator connection. – at the interface point between the installation and the network, e.g. in order to check the compliance of the connection agreement between a network operator and the customer. NOTE 1 – These instruments can also be used for other applications, e.g. inside commercial / industrial installations especially where comparable measurements are needed (i.e. data centers or petrochemical plants). These instruments are fixed-installed or portable. They are intended to be used indoors and/or outdoors. Devices such as digital fault recorders, energy/power meters, protection relays or circuit breakers may include power quality functions defined in 61000-4-30 class A or class S. If such devices are specified according to this standard, then this standard fully applies and applies in addition to the relevant product standard. This standard does not replace the relevant product standard. NOTE 2 – It is not the intent of this standard to address user interface or topics unrelated to device measurement performance. NOTE 3 – The standard does not cover post-processing and interpretation of the data, for example with a dedicated software.