IEEE C57.12.38-2025

This standard covers certain electrical, dimensional, and mechanical characteristics and safety requirements of single-phase, 60-Hz, liquid-filled, self-cooled, pad-mounted, compartmental-type distribution transformers. These transformers are rated 250 kVA and smaller with the high voltages of 34 500 GrdY/19 920 V and below for operation between one phase and grounded neutral and low voltage of 480/240 V and below. These transformers are generally used for step-down purposes from an underground primary cable supply. This standard covers the connector, bushing, and terminal arrangements for radial or loop feed systems. This standard does not cover all electrical and mechanical requirements of accessory devices that may be supplied with the transformer.