# ANSI/IEEE thermal circuit breaker symbol

Canonical URL: https://eloragrid.ai/symbols/ansi-thermal-circuit-breaker
Publisher: Elora Grid
Updated: 2026-10-14
Lookup label: CB TH
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 circuit breaker](https://eloragrid.ai/symbols/thermal-circuit-breaker)

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

## What it represents

The thermal breaker form adds a temperature-responsive protection concept to the circuit-interruption path. Reading it requires both the overload characteristic and the device's short-circuit rating; the small protection modifier is not a complete time-current curve.
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

- Keep the thermal function linked to the breaker it operates.
- 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

- Identify thermal setting
- Reference time-current data
- State breaking rating

## Important distinction

A thermal qualifier describes protection response, while a trip-contact symbol describes a separate control connection.

## Facts

- Convention evidence: Autodesk IEEE Symbol Preview — 1 Pole Circuit Breakers
- Public vendor block name: HCB11TH (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.