# ANSI/IEEE thermal-magnetic circuit breaker symbol

Canonical URL: https://eloragrid.ai/symbols/ansi-thermal-magnetic-circuit-breaker
Publisher: Elora Grid
Updated: 2026-10-14
Lookup label: CB TM
Drawing use: SLD, Schematic
Reference families: IEEE / ANSI, Manufacturer

## Symbol convention

Convention: IEEE / ANSI
Form: Autodesk IEEE-oriented 1 Pole Circuit Breakers 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: [Thermal-magnetic circuit breaker](https://eloragrid.ai/symbols/thermal-magnetic-circuit-breaker)

IEEE-oriented graphical reference for thermal-magnetic circuit breaker, with public vendor evidence and drawing-reading notes.

## What it represents

The thermal-magnetic form combines two protection responses associated with the same breaker. An expanded drawing may show the operating path and additional functional marks, but device selection and coordination still depend on the scheduled breaker and trip data.
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

- Read thermal and magnetic operating information separately.
- 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

- Name breaker model
- Document current and curve
- Reference coordination study

## Important distinction

The combination is different from an electronic relay issuing a trip to an otherwise separately protected breaker.

## Facts

- Convention evidence: Autodesk IEEE Symbol Preview — 1 Pole Circuit Breakers
- Public vendor block name: HCB11Q9 (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 — 1 Pole Circuit Breakers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-7F08A484-0517-4954-BD68-1648DDBC84A1.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.