IEEE C57.12.26-1992

This standard covers certain electrical, dimensional, and mechanical characteristics and takes into consideration certain safety features of three-phase, 60 Hz, mineral-oil-immersed, self-cooled, pad-mounted, compartmental-type distribution transformers with separable insulated high-voltage connectors. These transformers are rated 2500 kVA and smaller, with high voltages of 34 500 Grd Y/19 920 V and below and with low voltages of 480 V and below. These transformers are used generally for step-down purposes from an underground primary cable supply. NOTE — Refer to latest Federal regulations concerning polychlorinated biphenyl (PCB) contamination in transformers. This standard covers connector and terminal arrangements for both radial-feed and loop-feed systems. Either certain minimum dimensions (see Figs 1-4) or certain specific dimensions (see Figs 5.A-8) shall be specified. This standard does not cover the electrical and mechanical requirements of any accessory devices that may be supplied with the transformer.

This standard is intended for use as a basis for determining the performance, interchangeability, and safety of the equipment covered, and for assisting in the proper selection of such equipment.

New IEEE Standard - Inactive-Withdrawn. Withdrawn Standard. Withdrawn Date: Mar 06, 2000. No longer endorsed by the IEEE. This standard is intended for use as a basis for determining performance, interchangeability, and safety of the equipment covered, and for assisting in the proper selection of equipment. It covers certain electrical, dimensional, and mechanical characteristics and takes into consideration certain safety features of three-phase, 60 Hz, mineral-oil-immersed, self-cooled, pad-mounted, compartmental-type distribution transformers with separable insulated high-voltage connectors. These transformers are rated at 2500 kVA and smaller, with high voltages of 34 500 Grd Y/19 920 V and below and with low voltages of 480 V and below. These transformers are used generally for step-down purposes from an underground primary cable supply. Connector and terminal arrangements for both radial-feed and loop-feed systems are included.