This International Standard specifies the service conditions@ rated characteristics@ general structural requirements and test methods of prefabricated substations@ which are cable connected@ to be operated from inside or outside for alternating current of primary rated voltages above 1 kV and up to and including 52 kV1)@ and for a transformer of maximum power 1 600 kVA@ for service frequencies up to and including 60 Hz for outdoor installation in locations with public accessibility. Prefabricated substations can be situated at ground level or partially or completely below ground level.As no basic generally accepted IEC or IS0 standards are available concerning ageing or corrosion@ requirements covering these aspects are not included in this standard.1) The rated voltage on the secondary side should not exceed 1 kV.