{"schemaVersion":1,"slug":"ansi-four-way-switch","name":"ANSI four-way switch plan symbol","kind":"symbol","abbreviation":"S4","aliases":["S4 switch","four-way switch symbol","4-way switch"],"category":"installation-communications","drawingTypes":["GA"],"referenceFamilies":["IEEE / ANSI"],"summary":"US plan symbol S4 for a four-way switch placed between two three-way switches to add control points.","description":["The S4 symbol marks a four-way switch, which crosses the travellers between two three-way switches. Any number of S4 switches can be added along the travellers, so long corridors and rooms with several entries show S3 at the ends and S4 between.","Reading the plan, the installer checks that S4 never appears without a pair of S3 switches on the same group. The IEC equivalent is the intermediate switch.","The symbol gives no information about the device rating or style. Smart switching systems may replace this wiring scheme with a master and companion device, which should be noted."],"readingNotes":["Confirm two S3 switches exist on the same group.","Watch for smart-switch notes that change the wiring scheme."],"drawingChecklist":["Show S3 at each end.","Number control points for clarity.","State any smart-control alternative."],"distinction":"S3 changes over; S4 crosses two travellers and only works between S3 switches.","facts":[{"label":"Contact","value":"Crossover of two travellers"},{"label":"IEC equivalent term","value":"Intermediate switch"},{"label":"Artwork scope","value":"Original educational illustration; the exact ANSI or IEEE graphic and compliance are not certified"}],"references":[{"sourceId":"ieee-315","relevance":"Graphic-symbol standards context; not a source of reproduced artwork."}],"related":["iec-intermediate-light-switch","ansi-three-way-switch"],"artwork":"s28-ansi-four-way-switch","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEEE / ANSI","form":"Four-way switch, S4","reference":"US architectural electrical plan practice in the ANSI Y32.9 lineage, read alongside IEEE 315 context; independently drawn, not a certified IEEE or ANSI graphic."},"plainEnglish":{"title":"What does ANSI four-way switch plan mean?","introduction":"The S4 symbol marks a four-way switch, which crosses the travellers between two three-way switches. Any number of S4 switches can be added along the travellers, so long corridors and rooms with several entries show S3 at the ends and S4 between.","example":"Reading the plan, the installer checks that S4 never appears without a pair of S3 switches on the same group. The IEC equivalent is the intermediate switch.","drawings":"The symbol gives no information about the device rating or style. Smart switching systems may replace this wiring scheme with a master and companion device, which should be noted.","terms":[{"name":"Normally open / normally closed","meaning":"The contact state in the normal condition defined for the drawing."},{"name":"Rating","meaning":"A value stating the conditions for which equipment is specified."},{"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":"IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams","url":"https://standards.ieee.org/ieee/315/515/"}],"detail":"US plan symbol S4 for a four-way switch placed between two three-way switches to add control points. S3 changes over; S4 crosses two travellers and only works between S3 switches.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/ansi-four-way-switch","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/ansi-four-way-switch.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"ieee-315","title":"IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams","publisher":"IEEE Standards Association","url":"https://standards.ieee.org/ieee/315/515/","type":"standard","scope":"Graphic symbols and designation letters. IEEE lists this edition as Inactive-Reserved; it is a historical reference, not a claim of current compliance.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Graphic-symbol standards context; not a source of reproduced artwork."}]}