# Frame or chassis connection

Canonical URL: https://eloragrid.ai/symbols/iec-frame-or-chassis-connection
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: -
Drawing use: Schematic
Reference families: IEC

## Symbol convention

Convention: IEC
Form: Frame or chassis connection
Independent IEC-context illustration; not certified IEC geometry.

A connection to the metal frame or chassis of equipment, which may or may not itself be connected to earth.

## In plain English

### What does Frame or chassis connection mean?

The frame or chassis connection shows that a circuit point is connected to the metal structure of a device, drawn as a line ending in a comb or hatched mark. It is common on electronics, vehicle and machine wiring, where the chassis is used as a common reference or return.

### A simple example

A chassis connection is not automatically an earth connection. Equipment on a vehicle or isolated supply may have a chassis that is not connected to earth at all. Where the chassis is also protectively earthed, the protective earth symbol should be shown separately so the safety function is clear.

### What the drawings help you do

Do not assume the chassis is earthed. Look for a separate protective earth connection on the frame. A chassis connection ties to the equipment frame; a protective earth connection ties to the installation earthing system.

### This particular reference

A connection to the metal frame or chassis of equipment, which may or may not itself be connected to earth. A chassis connection ties to the equipment frame; a protective earth connection ties to the installation earthing system.

### Terms

- Terminal: An identified point where a conductor connects.
- Schematic: A drawing showing function and connections rather than physical appearance.

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.

- [AutoCAD Electrical: Earthing, sources and surge protection](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-1E3FDEAE-B4B2-417C-8075-108AA2C6E509.htm)
- [IEC-60617 symbol preview directory](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-7871E6EF-24D5-467E-9B74-321FEDC9DFDA.htm)


## What it represents

The frame or chassis connection shows that a circuit point is connected to the metal structure of a device, drawn as a line ending in a comb or hatched mark. It is common on electronics, vehicle and machine wiring, where the chassis is used as a common reference or return.
A chassis connection is not automatically an earth connection. Equipment on a vehicle or isolated supply may have a chassis that is not connected to earth at all. Where the chassis is also protectively earthed, the protective earth symbol should be shown separately so the safety function is clear.

## How to read it

- Do not assume the chassis is earthed.
- Look for a separate protective earth connection on the frame.

## Information to show or reference

- Show whether the chassis is earthed.
- Separate chassis returns from protective earthing.
- Identify the chassis bonding point.

## Important distinction

A chassis connection ties to the equipment frame; a protective earth connection ties to the installation earthing system.

## Facts

- Graphic cue: Line ending in a comb-like mark
- Earthing implied: No; check separately
- Preview: Original educational illustration; consult the publisher and applicable standard for the exact graphic

## Public references

- [AutoCAD Electrical: Earthing, sources and surge protection](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-1E3FDEAE-B4B2-417C-8075-108AA2C6E509.htm) — Autodesk. Public IEC-oriented earth and bonding forms.
- [IEC-60617 symbol preview directory](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-7871E6EF-24D5-467E-9B74-321FEDC9DFDA.htm) — Autodesk. Public directory of IEC-oriented symbol families.

## 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.