# ANSI/IEEE changeover contact symbol

Canonical URL: https://eloragrid.ai/symbols/ansi-changeover-contact
Publisher: Elora Grid
Updated: 2026-10-14
Lookup label: CO
Drawing use: Schematic
Reference families: IEEE / ANSI, Manufacturer

## Symbol convention

Convention: IEEE / ANSI
Form: Autodesk IEEE-oriented Relays and Contacts functional form
Autodesk explicitly publishes this block under IEEE Symbol Preview. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.
Related representation: [Changeover contact](https://eloragrid.ai/symbols/changeover-contact)

IEEE-oriented graphical reference for changeover contact, with public vendor evidence and drawing-reading notes.

## What it represents

The Form C relay contact representation links a common connection to alternative contact paths. The reader must identify common, normally closed and normally open terminals, with transition timing specified separately where overlap matters.
This is a convention-specific lookup based on the publisher's IEEE-labelled preview. The geometry here is independently drawn to explain the connection or operation; it is not a certified reproduction of the standard graphic.

## How to read it

- Trace the common terminal to each throw using the stated reference state.
- Read the selected library and the project legend together. A vendor block identifier is meaningful within its named library and is not a universal standard-symbol code.

## Information to show or reference

- Label common/NO/NC
- Identify parent relay
- Reference transfer sequence

## Important distinction

Form C identifies a changeover contact arrangement; it does not by itself establish make-before-break behaviour.

## Facts

- Convention evidence: Autodesk IEEE Symbol Preview — Relays and Contacts
- Public vendor block name: HCR23R (Autodesk identifier; not an IEEE symbol number)
- Standards context: IEEE/ANSI 315-1975 covers diagram graphics. IEEE lists this edition as Inactive-Reserved.
- Artwork scope: Original functional illustration; exact standard glyph and compliance are not certified

## Public references

- [Autodesk IEEE Symbol Preview — Relays and Contacts](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-F8EAC387-53CF-45FE-BE6A-C0C8FB3C1B22.htm) — Autodesk. Exact public IEEE-oriented category page verifying the component name and vendor block identifier.
- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/) — IEEE Standards Association. Graphic-symbol standards context and official status; not a source of reproduced artwork.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.