IEC 62271-212:2016 specifies the service conditions, rated characteristics, general structural requirements and test methods of the assemblies of the main electrical functional units of a high-voltage/low-voltage distribution substation, duly interconnected, for alternating current of rated operating voltages above 1 kV and up to and including 52 kV on the high-voltage side, service frequency 50 Hz or 60 Hz. This assembly is to be cable-connected to the network, and intended for installation within an indoor or outdoor closed electrical operating area. This publication is to be read in conjunction with IEC 62271-1:2007