Second Edition of CSA C227.4: Standard for Distribution Transformers with High-Voltage Connectors

Untitled-1CSA has released a second edition of CSA C227.4, pertaining to three-phase, pad-mounted distribution transformers with separable insulated high-voltage connectors. This standard update supersedes the first edition published in 1978 and can be purchased from CSA’s website.


This Standard specifies the requirements for three-phase, pad-mounted distribution transformers, consisting of a transformer and a cable entrance compartment with provision for separable insulated high-voltage connectors, intended primarily for operation by electric utilities on three-phase underground distribution systems having primary voltages as shown in Clause 4.6.
Note: The operation of transformers complying with this Standard by other than an electric utility may be subject to additional requirements by the electrical inspection authority having jurisdiction.

This Standard applies to three-phase, 60 Hz, pad-mounted, liquid-filled distribution transformers, rated at 3000 kV.A or below, with an insulation class of 18 kV or less, and with separable insulated high-voltage connectors. The transformers are suitable for mounting outdoors on pads without additional protective enclosures.

This Standard includes voltage ratings, kV.A ratings, certain mechanical characteristics, and test procedures. The Standard also includes the following performance characteristics: energy efficiency (in accordance with CAN/CSA-C802.1), temperature rise, loading capabilities, audible sound level, and radio influence voltage (RIV).

When this equipment is intended for operation by other than an electric utility, it shall be the purchaser’s responsibility to ensure that the unit meets the requirements of the appropriate electrical inspection authority.

This Standard allows for the replacement of a dead-front, pad-mounted unit by another of the same basic physical size from a different manufacturer, without modifications to cables or pad. This Standard covers terminal arrangements for both radial and loop-feed systems, including certain minimum dimensions and certain specific dimensions.


*Description from CSA’s website.

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