{"schemaVersion":1,"slug":"iec-two-way-light-switch","name":"Two-way light switch plan mark","kind":"symbol","abbreviation":"S2W","aliases":["two-way switch","three-way switch (US term)","staircase switch"],"category":"installation-communications","drawingTypes":["GA"],"referenceFamilies":["IEC"],"summary":"Plan mark for a two-way switch used in pairs so one lighting group can be switched from two places.","description":["Two-way switches are installed in pairs at either end of a corridor or staircase so either switch changes the state of the lights. The IEC-style plan form draws the switch circle with strokes in two opposite directions, each with a tick, showing the changeover action.","On a plan the pair is linked by a switching line to the luminaire group. The electrician reads the pair to run strappers between the two switches; where an intermediate switch is shown between them, a third location can also control the lights.","The symbol does not show the wiring method, which can be conventional strappers or a converted arrangement. It also does not tell you the gang count unless written."],"readingNotes":["Expect two-way switches in pairs; a single two-way switch usually signals a drafting error or a spare.","Look for an intermediate switch between the pair on long runs."],"drawingChecklist":["Show both switch positions and the controlled luminaires.","Mark any intermediate switches.","Note gang count where plates are shared."],"distinction":"In US terminology this is a three-way switch; the US four-way switch corresponds to the IEC intermediate switch.","facts":[{"label":"Operation","value":"Changeover contact, used in pairs"},{"label":"US equivalent term","value":"Three-way switch"},{"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":"switching-devices","relevance":"Context for functional control switching."}],"related":["iec-intermediate-light-switch","iec-one-way-light-switch","ansi-three-way-switch"],"artwork":"s28-iec-two-way-light-switch","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"Two-way 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 Two-way light switch plan mark mean?","introduction":"Two-way switches are installed in pairs at either end of a corridor or staircase so either switch changes the state of the lights. The IEC-style plan form draws the switch circle with strokes in two opposite directions, each with a tick, showing the changeover action.","example":"On a plan the pair is linked by a switching line to the luminaire group. The electrician reads the pair to run strappers between the two switches; where an intermediate switch is shown between them, a third location can also control the lights.","drawings":"The symbol does not show the wiring method, which can be conventional strappers or a converted arrangement. It also does not tell you the gang count unless written.","terms":[{"name":"Schematic","meaning":"A drawing showing function and connections rather than physical appearance."}],"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":"Elementary switching devices","url":"https://www.electrical-installation.org/enwiki/Elementary_switching_devices"}],"detail":"Plan mark for a two-way switch used in pairs so one lighting group can be switched from two places. In US terminology this is a three-way switch; the US four-way switch corresponds to the IEC intermediate switch.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/iec-two-way-light-switch","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/iec-two-way-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":"switching-devices","title":"Elementary switching devices","publisher":"Schneider Electric — Electrical Installation Guide","url":"https://www.electrical-installation.org/enwiki/Elementary_switching_devices","type":"manufacturer","scope":"Explains disconnectors, load-break switches, contactors and fuses. The manufacturer diagrams remain at the source.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Context for functional control switching."}]}