In electric power systems and industrial automation, ANSI Device Numbers can be used to identify equipment and devices in a system such as relays, circuit breakers, or instruments.

Feb 23, 2022 · In this Info Byte, learn the purpose and reason behind the often-confusing terminal numbers. You might still have to look up those wiring diagrams, but perhaps we can remove some of …

Aug 29, 2017 · They’re called DIN-standard relay terminal numbers; DIN stands for Deutsches Institut für Normung (German Institute for Standards). Sometime around the middle of the last century, …

Mar 22, 2012 · Protective relays are commonly referred to by standard device numbers. For example, a time overcurrent relay is designated a 51 device, while an instantaneous overcurrent is a 50 device.

Nov 12, 2022 · We’ve put together this guide to help you understand exactly what the numbers on a relay refer to. Read on to learn more about the numbers on a relay and how to use them. The …

Decode relay terminal numbers 30, 85, 86, 87 and their critical functions in industrial automation. Learn what each designation means for proper wiring and reliable system operation.

Apr 27, 2023 · This article will explain the basics of the relay numbers used to design a relay’s functionality.

Sep 11, 2025 · This guide breaks down the naming conventions used by Schneider, Siemens, IDEC (Izumi), Finder and OMRON. We focus on model number structure, standard terminal numbering, …

In the design of electrical power systems, the ANSI Standard Device Numbers (ANSI /IEEE Standard C37.2) denote what features a protective device supports (such as a relay or circuit breaker).

There is a NEMA standard and an IEC standard for relay wiring, that's why each terminal has two numbers assigned. One is shown in brackets and the other not in brackets.