# Photoelectric light switch plan mark

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

## Symbol convention

Convention: IEC
Form: Light-sensitive 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 light-sensitive switch that turns external or perimeter lighting on at dusk and off at dawn.

## In plain English

### What does Photoelectric light switch plan mark mean?

A photoelectric switch, or photocell, measures ambient light and operates a lighting circuit at a set lux threshold. Plans draw a small switch or box with inward arrows to indicate light received, placed where the cell can see the sky without seeing the luminaires it controls.

### A simple example

Photocells are often combined with time switches so that lighting comes on at dusk but goes off at a fixed time. The plan and schedule should show both devices and their logic.

### What the drawings help you do

The mark does not give the threshold, time delay or contactor rating. Large lighting loads are usually switched by a contactor operated by the cell.

### This particular reference

Plan mark for a light-sensitive switch that turns external or perimeter lighting on at dusk and off at dawn. A light-dependent resistor is a component; a photoelectric switch is a complete lighting control device on the plan.

### Terms

- Normally open / normally closed: The contact state in the normal condition defined for the drawing.
- Coil: A wound conductor that can produce a magnetic field when energised.
- Signal: Electrical information passed between devices, rather than necessarily the main power supply.

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: Radiation qualifiers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-EABC81B4-549D-49C9-A0F5-086DD204A689.htm)


## What it represents

A photoelectric switch, or photocell, measures ambient light and operates a lighting circuit at a set lux threshold. Plans draw a small switch or box with inward arrows to indicate light received, placed where the cell can see the sky without seeing the luminaires it controls.
Photocells are often combined with time switches so that lighting comes on at dusk but goes off at a fixed time. The plan and schedule should show both devices and their logic.
The mark does not give the threshold, time delay or contactor rating. Large lighting loads are usually switched by a contactor operated by the cell.

## How to read it

- Check the cell location for a clear view of daylight.
- Look for a contactor or time switch in the same control scheme.

## Information to show or reference

- State lux setting range.
- Show associated contactor or time switch.
- Orient the cell away from controlled luminaires.

## Important distinction

A light-dependent resistor is a component; a photoelectric switch is a complete lighting control device on the plan.

## Facts

- Input: Ambient daylight level
- Common pairing: Time switch and lighting contactor
- 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: Radiation qualifiers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-EABC81B4-549D-49C9-A0F5-086DD204A689.htm) — Autodesk. Public IEC-oriented radiation qualifier family for the received-light arrows.

## 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.