IEEE C37.2-1987 defines standard electrical power system device function numbers used in power, energy, and industry applications. It helps engineers, planners, and maintenance teams identify protective relays, control functions, and related devices in a consistent way across drawings, equipment schedules, and operating documents. By standardizing function numbering, IEEE C37.2-1987 supports clearer communication, fewer interpretation errors, and more reliable coordination in electrical power system work.

IEEE C37.2-1987 overview

This standard addresses the numbering system commonly used to designate electrical device functions in power system applications. In practical terms, it gives a shared technical language for identifying devices such as relays, breakers, and control elements within substations, switchgear, and associated power equipment. The document is especially useful where consistent notation is needed for design, documentation, commissioning, and maintenance. As a superseded standard, IEEE C37.2-1987 remains relevant for legacy reference and historical equipment documentation.

Typical use cases

IEEE C37.2-1987 is typically used when preparing electrical schematics, protection and control diagrams, relay panel schedules, and equipment documentation for power systems. It is relevant in substations, utility distribution installations, industrial power networks, and other applications where standardized device identification improves clarity. The function numbers may also be referenced during troubleshooting, upgrades, or recordkeeping for older installations that still rely on the same numbering conventions.

Why this standard matters

Using a consistent device function numbering scheme helps reduce confusion during design review, procurement, testing, and field service. IEEE C37.2-1987 supports better coordination between engineers, contractors, and operators by making power-system device references easier to interpret. That consistency can lower documentation errors, improve maintenance efficiency, and reduce the risk of miscommunication when comparing drawings or replacing equipment in existing installations. For organizations managing legacy power infrastructure, the standard remains a useful reference point.

• Standard electrical device function numbers
• Power system identification and notation
• Legacy reference for older installations
• Useful for drawings, schedules, and controls
• Supports consistent engineering documentation