# Changeover contact

Canonical URL: https://eloragrid.ai/symbols/changeover-contact
Publisher: Elora Grid
Updated: 2026-10-13
Lookup label: CO
Drawing use: Schematic
Reference families: IEC, IEEE / ANSI

A contact arrangement switching a common connection between two contact paths.

## What it represents

A changeover contact connects a common terminal to one of two alternative contact paths according to its operating state. Form C and SPDT are terms commonly encountered for this arrangement. The actual terminal numbering and transfer behaviour come from the selected device.
The schematic should make the common terminal and normal state clear. A mirrored or differently oriented drawing can retain the same logical arrangement, but terminal associations must not be inferred from appearance alone.

## How to read it

- Locate the common terminal and determine the path shown in the defined normal state.
- Use device data to identify transfer timing and any special overlap behaviour.

## Information to show or reference

- Identify the common terminal.
- Link both switched paths to the parent device.
- Keep terminal identifiers consistent with wiring documentation.

## Important distinction

Two unrelated NO/NC contacts are not automatically one changeover contact. Confirm whether they share a common connection and operating mechanism.

## Facts

- Connections: Common and two alternative paths
- Alternative terms: Form C; SPDT
- Transfer characteristics: Device-specific
- Public Autodesk reference names: HCR23R, VCR23R (vendor identifiers, not IEC symbol IDs)

## Public references

- [Relays and contacts: public symbol reference](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-011C62B8-9EC8-485C-B47D-B22A3F7B7574.htm) — Autodesk. Public Form C relay contact variants.

## 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.