scope:

NVN-IEC/TS 62257-9-4 which is a technical specification, specifies the general requirements for the design and the implementation of a user's installation. This part of IEC 62257 applies to single phase user's electrical installations with maximum power of 500 VA, in Decentralized Rural Electrification Systems (DRES). This part of IEC 62257 is applicable to installations supplied by an a.c microgrid (120 V or 220 V or 230 V or 240 V) and to installations encompassing their own single-unit a.c. micropower plant (120 V or 220 V or 230 V or 240 V) or d.c micropower plant (12 V or 24 V). The part of IEC 62257 applies neither to the electric power production and distribution installations described in the clauses concerning micropower plants and microgrids, nor to user electrical equipment. It details the rules governing the design and construction of consumer's electrical installations for the purpose of ensuring the safety of persons and property, and satisfactory operation in accordance with the purpose for which the installations are designed. It applies to new installations and modifications of existing installations.