# ANSI/IEEE thermocouple with terminal board symbol

Canonical URL: https://eloragrid.ai/symbols/ansi-thermocouple-with-terminal-board
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: TC
Drawing use: Schematic
Reference families: IEEE / ANSI, Manufacturer

## Symbol convention

Convention: IEEE / ANSI
Form: Autodesk IEEE-oriented Instrumentation and Sensors form: Thermocouple with Terminal Board
Autodesk publishes this block under its IEEE Symbol Preview. The counterpart is the matching functional concept in the library; no equivalence of every detailed standard graphic is asserted.
Related representation: [Thermocouple with terminal board](https://eloragrid.ai/symbols/iec-thermocouple-with-terminal-board)

IEEE-library thermocouple form that adds the head terminal board where element leads change to field cable.

## In plain English

### What does ANSI/IEEE thermocouple with terminal board mean?

This form adds the terminal board in the thermocouple head to the basic junction symbol. It is useful on loop and wiring diagrams because the terminal board marks the boundary between the element, which is replaced with the sensor, and the field extension cable, which stays in place.

### A simple example

Drawing the terminal board makes polarity at the changeover explicit, but it still does not tell you the thermocouple type or whether the head contains a transmitter. If a head-mounted transmitter is fitted, the output becomes a current loop and should be drawn as such.

### What the drawings help you do

Use the terminal numbers to check polarity at the head. Confirm whether a head transmitter replaces the direct millivolt connection. The terminal-board form shows the head connection point; the plain thermocouple form shows only the junction and leads.

### This particular reference

IEEE-library thermocouple form that adds the head terminal board where element leads change to field cable. The terminal-board form shows the head connection point; the plain thermocouple form shows only the junction and leads.

### Terms

- Terminal: An identified point where a conductor connects.
- Signal: Electrical information passed between devices, rather than necessarily the main power supply.
- Rating: A value stating the conditions for which equipment is specified.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [Autodesk IEEE Symbol Preview — Instrumentation and Sensors](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-F44D5059-4728-40BD-B9BA-0DE7CFDFAACF.htm)
- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/)


## What it represents

This form adds the terminal board in the thermocouple head to the basic junction symbol. It is useful on loop and wiring diagrams because the terminal board marks the boundary between the element, which is replaced with the sensor, and the field extension cable, which stays in place.
Drawing the terminal board makes polarity at the changeover explicit, but it still does not tell you the thermocouple type or whether the head contains a transmitter. If a head-mounted transmitter is fitted, the output becomes a current loop and should be drawn as such.

## How to read it

- Use the terminal numbers to check polarity at the head.
- Confirm whether a head transmitter replaces the direct millivolt connection.

## Information to show or reference

- Number the head terminals
- Show extension cable type
- Note any head-mounted transmitter

## Important distinction

The terminal-board form shows the head connection point; the plain thermocouple form shows only the junction and leads.

## Facts

- Convention evidence: Autodesk IEEE Symbol Preview, Instrumentation and Sensors
- Public vendor block name: HTC1LTB / HTC1RTB and vertical forms (Autodesk identifier; not an IEEE symbol number)
- Boundary shown: Sensor element to field cable changeover
- Artwork scope: Original functional illustration; exact standard glyph and compliance are not certified

## Public references

- [Autodesk IEEE Symbol Preview — Instrumentation and Sensors](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-F44D5059-4728-40BD-B9BA-0DE7CFDFAACF.htm) — Autodesk. Public IEEE-oriented Instrumentation and Sensors preview listing the Thermocouple with Terminal Board block and its vendor 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.