# Make-before-break changeover contact

Canonical URL: https://eloragrid.ai/symbols/make-before-break-changeover-contact
Publisher: Elora Grid
Updated: 2026-10-13
Lookup label: MBB
Drawing use: Schematic
Reference families: IEC, Manufacturer

A make-before-break changeover contact establishes the next path before releasing the previous path during its documented transfer.

## What it represents

A make-before-break changeover contact establishes the next path before releasing the previous path during its documented transfer. The temporary overlap must be understood for the connected circuits.

## How to read it

- Identify any circuits that would be interconnected during the overlap.
- The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation.

## Information to show or reference

- Label common and throw terminals
- State overlap sequence
- Reference connected-circuit compatibility

## Important distinction

A break-before-make transfer opens the previous path before establishing the next.

## Facts

- Drawing role: Contact state
- Representation scope: Functional concept; not an official standard graphic or a product footprint
- Public vendor block reference: HSW1SC7_F, VSW1SC7_F (Autodesk identifiers; not IEC symbol numbers)
- Identifier status: The short label is a functional lookup label, not an assigned IEC or IEEE symbol number. Any separately listed Autodesk code is a verified vendor block name.

## Public references

- [AutoCAD Electrical: Level, flow, keyed and measurement switches](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-1FB94435-C954-4479-BD97-25796DB8F728.htm) — Autodesk. Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic.

## 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.