Three-Phase Live-Front Pad-Mounted Distribution Transformers

1.1 This Standard specifies requirements for three-phase live-front pad-mounted distribution transformer units that (a) consist of a transformer and a separable or integral cable entrance compartment; (b) are rated 75 to 3000 kV-A and intended for operation on three-phase underground distribution systems having the preferred rated voltages specified in Tables 1 and 2; and (c) are intended for mounting outdoors on pads without additional protective enclosures.

1.2 This Standard does not apply to equipment involving enclosures for housing a separate three-phase transformer or a bank of single-phase transformers (see CAN/CSA-C2.1). Note: It is possible that transformers complying with this Standard will, if operated by a body other than an electrical utility, be subject to additional requirements specified by the electrical inspection authority having jurisdiction.

1.3 This Standard allows for the replacement of a live-front pad-mounted unit by another unit of the same basic physical size from a different manufacturer without modification to cables or pad. This Standard covers terminal arrangements for both radial and loop-feed systems, including certain minimum and other dimensions. Note: This concept should not be understood to imply that the cable entrance compartment of one manufacturer's transformer will be compatible with that of another manufacturer's transformer.