{"schemaVersion":1,"slug":"iec-photoelectric-light-switch","name":"Photoelectric light switch plan mark","kind":"symbol","abbreviation":"PE","aliases":["photocell","daylight switch","dusk-to-dawn sensor"],"category":"installation-communications","drawingTypes":["GA"],"referenceFamilies":["IEC"],"summary":"Plan mark for a light-sensitive switch that turns external or perimeter lighting on at dusk and off at dawn.","description":["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."],"readingNotes":["Check the cell location for a clear view of daylight.","Look for a contactor or time switch in the same control scheme."],"drawingChecklist":["State lux setting range.","Show associated contactor or time switch.","Orient the cell away from controlled luminaires."],"distinction":"A light-dependent resistor is a component; a photoelectric switch is a complete lighting control device on the plan.","facts":[{"label":"Input","value":"Ambient daylight level"},{"label":"Common pairing","value":"Time switch and lighting contactor"},{"label":"Exact standard graphic","value":"Not reproduced here; confirm the form against IEC 60617 and the project legend"}],"references":[{"sourceId":"iec-diagrams","relevance":"IEC graphical symbol context; independently drawn here."},{"sourceId":"iec-public-radiation","relevance":"Public IEC-oriented radiation qualifier family for the received-light arrows."}],"related":["light-dependent-resistor","iec-time-switch-plan-mark","iec-presence-detector-lighting"],"artwork":"s28-iec-photoelectric-light-switch","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"Light-sensitive switch","reference":"IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier."},"plainEnglish":{"title":"What does Photoelectric light switch plan mark mean?","introduction":"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.","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.","drawings":"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.","terms":[{"name":"Normally open / normally closed","meaning":"The contact state in the normal condition defined for the drawing."},{"name":"Coil","meaning":"A wound conductor that can produce a magnetic field when energised."},{"name":"Signal","meaning":"Electrical information passed between devices, rather than necessarily the main power supply."}],"diagram":"flow","steps":["Identify the device and form","Read the connections and state","Check the equipment reference"],"caption":"A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.","sources":[{"label":"IEC graphical symbols for diagrams","url":"https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/"},{"label":"Autodesk IEC-60617 preview: Radiation qualifiers","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-EABC81B4-549D-49C9-A0F5-086DD204A689.htm"}],"detail":"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.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/iec-photoelectric-light-switch","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/iec-photoelectric-light-switch.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"iec-diagrams","title":"IEC graphical symbols for diagrams","publisher":"IEC","url":"https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/","type":"standard","scope":"IEC 60617 and related symbol-design publications. Full database access requires a subscription.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"IEC graphical symbol context; independently drawn here."},{"id":"iec-public-radiation","title":"Autodesk IEC-60617 preview: Radiation qualifiers","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-EABC81B4-549D-49C9-A0F5-086DD204A689.htm","type":"cad-reference","scope":"Public publisher IEC-context family names and vendor block references. No vendor images or CAD library files are reproduced, and vendor tokens are not presented as verified IEC database identifiers.","checkedOn":"2026-10-14","reuse":"link-only","relevance":"Public IEC-oriented radiation qualifier family for the received-light arrows."}]}