IEEE C57.12.23-2009

This standard covers certain electrical, dimensional, and mechanical characteristics and takes into consideration certain safety features of single-phase, 60 Hz, liquid-immersed, self-cooled, submersible distribution transformers with separable insulated high-voltage connectors. These transformers are rated 167 kVA and smaller, with high voltages of 25 000 V and below and with low voltages of 600 V and below. These transformers are generally used for step-down purposes from an underground primary cable supply. These transformers are typically installed in an enclosure below ground level, operated from above and suitable for submerged operation. This standard does not cover the electrical and mechanical requirements of any accessory devices that may be supplied with the transformer.