# Dimmer switch plan mark

Canonical URL: https://eloragrid.ai/symbols/iec-dimmer-switch
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: SD
Drawing use: GA
Reference families: IEC

## Symbol convention

Convention: IEC
Form: Dimmer switch
IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.

Plan mark for a switch that varies lamp brightness, drawn as a switch with an added variability arrow.

## In plain English

### What does Dimmer switch plan mark mean?

A dimmer varies the power delivered to luminaires using phase-cut electronics or a control signal. IEC-style plans typically draw the switch mark with an oblique arrow or a small adjustment mark to show continuous variation, and the switching line links it to the dimmed group.

### A simple example

Dimmer compatibility with LED drivers is a frequent site problem, so the symbol is usually backed by a schedule stating the dimming method: leading edge, trailing edge, 0-10 V or DALI. The reader should check that every luminaire on the dimmed group is dimmable by that method.

### What the drawings help you do

The plan mark does not state the dimming technology or minimum load. A rotary or push dimmer looks the same on the plan.

### This particular reference

Plan mark for a switch that varies lamp brightness, drawn as a switch with an added variability arrow. A one-way switch has no variability mark; the dimmer adds continuous control of light output.

### Terms

- Phase: One of the related AC waveforms in a power system.
- Signal: Electrical information passed between devices, rather than necessarily the main power supply.
- 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.

- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/)
- [Autodesk IEC-60617 preview: Operating-device and function qualifiers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-3598E18D-9F8A-48CE-83D0-4CEBA0AE869C.htm)


## What it represents

A dimmer varies the power delivered to luminaires using phase-cut electronics or a control signal. IEC-style plans typically draw the switch mark with an oblique arrow or a small adjustment mark to show continuous variation, and the switching line links it to the dimmed group.
Dimmer compatibility with LED drivers is a frequent site problem, so the symbol is usually backed by a schedule stating the dimming method: leading edge, trailing edge, 0-10 V or DALI. The reader should check that every luminaire on the dimmed group is dimmable by that method.
The plan mark does not state the dimming technology or minimum load. A rotary or push dimmer looks the same on the plan.

## How to read it

- Check the dimming method in the schedule.
- Confirm every luminaire in the group is compatible.

## Information to show or reference

- State dimming method and rated load.
- Link to the dimmed luminaire group.
- Note minimum load for LED circuits.

## Important distinction

A one-way switch has no variability mark; the dimmer adds continuous control of light output.

## Facts

- Graphic cue: Switch mark with an oblique variability arrow
- Key schedule item: Dimming method and load rating
- Exact standard graphic: Not reproduced here; confirm the form against IEC 60617 and the project legend

## Public references

- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/) — IEC. IEC graphical symbol context; independently drawn here.
- [Autodesk IEC-60617 preview: Operating-device and function qualifiers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-3598E18D-9F8A-48CE-83D0-4CEBA0AE869C.htm) — Autodesk. Public IEC-oriented qualifier family showing how adjustability is added to a base symbol.

## 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.