This part of IEC 61557 specifies requirements for power metering and monitoring devices (PMD) that measure and monitor the electrical quantities within electrical distribution systems, and optionally other external signals. These requirements also defin the performance of PMD in single- and three-phace AC or DC systems having rated voltages up to 1000 V AC or up to 1500 V DC. These devices are fixed or portable. They are intended to be used indoors and/or outdoors. Power metering and monitoring devices (PMD), as defined in this document, give additional safety information, which aids the verification of the installation and enhances the performance of the distribution systems. Additionally, this document specifies requirements for measurement functions dedicated to metering and monitoring of electrical parameters called power metering and monitoring function (PMF) which can be embedded in equipment (EMPF) that is not classified as PMD and for which the main function is not power metering and monitoring. Requirements for power metering and monitoring function (PMF) and additional requirements for equipments embedding power metering and monitoring function (EPMF) are described in Annex H. The power metering and monitoring devices (PMD) for electrical parameters described in this document are used for general industrial and commercial applications. This document does not address functional safety and cyber security aspects. This document is not applicable to: - electricity metering equipment that complies with IEC 62053-21, IEC 62053-22, IEC 62053-23 and IEC 62053-24. Nevertheless, uncertainties defined in this document for active and reactive energy measurement are derived from those defined in IEC 62053 (all parts); - the measurement and monitoring of electrical parameters defined in IEC 61557-2 to IEC 61557-9 and IEC 61557-13 or in IEC 62020; - power quality instrument (PQI) according IEC 62586 (all parts); - devices covered by IEC 60051 (all parts) (direct acting analogue electrical measuring instrument). Note 1 Generally such types of devices are used in the following applications or for the following general needs: - energy management inside the installation, such as facilitating the implementation of documents such as ISO 50001 and IEC 60364-8-1; - monitoring and/or measurement of electrical parameters; - measurement and/or monitoring of the quality of energy inside commercial/industrial installations. Note 2 A measuring and monitoring device of electrical parameters usually consists of several functional modules. All or some of the functional modules are combined in one device. Examples of fuctnional modules are: - measurement and monitoring of several electrical parameters simultaneously; - energy measurement and/or monitoring, as well as sometimes compliance with aspects of building regulations; - alarms functions; - demand side quality (current and voltage harmonics, over/under voltages, voltage dips and swells, etc.). Note 3 PMD are historically called power meter, power monitor, power monitor device, power energy monitoring device, power analyser, multifunction meter, measuring multifunction equipment, energe meters. Note 4 Metering, measuring and monitoring applications are explained in Annex A.