# Thermal-magnetic circuit breaker

Canonical URL: https://eloragrid.ai/symbols/thermal-magnetic-circuit-breaker
Publisher: Elora Grid
Updated: 2026-10-13
Lookup label: CB TM
Drawing use: SLD, Schematic
Reference families: IEC, Manufacturer

A thermal-magnetic breaker combines overload response with a magnetic response to high current.

## What it represents

A thermal-magnetic breaker combines overload response with a magnetic response to high current. Its functional annotation helps distinguish the trip mechanism from an electronic trip unit.

## How to read it

- A curve designation alone does not state every operating limit or breaking rating.
- 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

- Record rated current and curve
- Show protected poles
- Reference short-circuit rating

## Important distinction

An electronic trip unit may provide similar protection functions through a different measurement and operating system.

## Facts

- Drawing role: Circuit interruption
- Representation scope: Functional concept; not an official standard graphic or a product footprint
- Public vendor block reference: HCB11Q9, VCB11Q9 (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

- [Circuit-breaker symbol variants](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-DB1548A3-A4D3-47E5-86AC-37000DC57D80.htm) — Autodesk. Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic.
- [Fundamental characteristics of a circuit-breaker](https://www.electrical-installation.org/enwiki/Fundamental_characteristics_of_a_circuit-breaker) — Schneider Electric — Electrical Installation Guide. 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.