IEEE C57.12.23-2009

C57.12.23-2009 is a technical standard for phase transformers rated at 167 kVA and smaller, with high voltage at 25,000 V and below and low voltage at 600 V and below. This redline edition helps engineers, purchasers, and compliance teams see the applicable requirements for compact power and energy equipment in one place. It is especially relevant where transformer design, rating, and performance must align with defined electrical limits and established industry practice.

C57.12.23-2009 overview

This standard addresses phase transformer requirements within a clearly bounded voltage and kVA range, making it useful for specifying smaller distribution-class equipment. C57.12.23-2009 is intended to support consistent design and evaluation of transformers used in power, energy, and related industrial applications. By setting expectations around the equipment scope, it helps frame manufacturing, testing, and procurement decisions for transformers that operate within these ratings and need to meet recognized technical criteria.

Typical use cases

This document is commonly used when selecting or reviewing phase transformers for low-voltage secondary systems, site power distribution, or equipment-level voltage conversion. It may apply to utility-connected installations, industrial facilities, and other electrical systems where transformer size and voltage limits fall within the stated scope. The standard can also support engineering teams that need a reference for comparing transformer designs, checking ratings, or aligning purchase specifications with expected application conditions.

Why this standard matters

For buyers, designers, and inspectors, C57.12.23-2009 matters because it helps reduce ambiguity around what qualifies as compliant transformer equipment in this rating class. Clear requirements support safer procurement, more consistent testing, and better control over design and performance expectations. In practice, the standard can help limit mismatches between system needs and transformer capability, which is important when coordinating insulation levels, voltage compatibility, and application-specific reliability in power and energy environments.

• Phase transformers up to 167 kVA
• High voltage 25,000 V and below
• Low voltage 600 V and below
• Redline edition for change review
• Relevant to power and energy applications