IEEE C57.12.38-2009

C57.12.38-2009 is a technical standard for phase distribution transformers used in power and energy applications, covering high voltage ratings up to 34 500 GrdY/19 920 V and low voltage at 240/120 V for units 167 kVA and smaller. It is relevant to transformer design and procurement where voltage class, size, and service conditions must be clearly defined. For utilities and related engineering work, this document helps support consistent equipment selection and application.

What is C57.12.38-2009?

C57.12.38-2009 defines requirements for phase distribution transformers within a specific voltage and kVA range, with a focus on electrical ratings and related construction expectations. In practical terms, it is the kind of specification used to align transformer design, dimensions, and performance criteria for distribution service. The standard helps establish a common technical basis for equipment intended for high-voltage primary systems and 240/120 V secondary supply, which is important when comparing products or checking compliance.

Where is C57.12.38-2009 used?

This standard is commonly used in utility distribution systems, substation-adjacent feeder applications, and other power delivery settings where single-phase or phase distribution transformers step voltage down to service-level loads. It is especially relevant for installations serving residential, light commercial, and mixed-load circuits that require 240/120 V output. In engineering, procurement, and field specification work, C57.12.38-2009 supports consistent selection of transformers sized at 167 kVA and below.

Why is C57.12.38-2009 important?

C57.12.38-2009 matters because it helps control how distribution transformers are designed, rated, and evaluated for a defined service range. That reduces ambiguity during purchasing, testing, and acceptance, especially when voltage compatibility and load capacity must be matched carefully. The standard can also help limit installation risk by promoting consistency in equipment expectations. For suppliers, utilities, and engineers, using the same technical reference supports clearer compliance decisions and more reliable interchangeability.

• Phase distribution transformer requirements
• High-voltage class up to 34 500 GrdY/19 920 V
• 240/120 V low-voltage secondary service
• Units rated 167 kVA and smaller
• Applicable to power and energy applications