{"schemaVersion":1,"slug":"make-before-break-changeover-contact","name":"Make-before-break changeover contact","kind":"symbol","abbreviation":"MBB","aliases":["HSW1SC7_F","VSW1SC7_F"],"category":"control-circuits","drawingTypes":["Schematic"],"referenceFamilies":["IEC","Manufacturer"],"summary":"A make-before-break changeover contact establishes the next path before releasing the previous path during its documented transfer.","description":["A make-before-break changeover contact establishes the next path before releasing the previous path during its documented transfer. The temporary overlap must be understood for the connected circuits."],"readingNotes":["Identify any circuits that would be interconnected during the overlap.","The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation."],"drawingChecklist":["Label common and throw terminals","State overlap sequence","Reference connected-circuit compatibility"],"distinction":"A break-before-make transfer opens the previous path before establishing the next.","facts":[{"label":"Drawing role","value":"Contact state"},{"label":"Representation scope","value":"Functional concept; not an official standard graphic or a product footprint"},{"label":"Public vendor block reference","value":"HSW1SC7_F, VSW1SC7_F (Autodesk identifiers; not IEC symbol numbers)"},{"label":"Identifier status","value":"The short label is a functional lookup label, not an assigned IEC or IEEE symbol number. Any separately listed Autodesk code is a verified vendor block name."}],"references":[{"sourceId":"pub-symbol-misc-switches","relevance":"Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic."}],"related":["normally-open-contact","normally-closed-contact"],"artwork":"edu-make-before-break-changeover-contact","publishedOn":"2026-10-13","updatedOn":"2026-10-13","provenance":"independent-public-research","url":"https://eloragrid.ai/symbols/make-before-break-changeover-contact","illustration":{"url":"https://eloragrid.ai/library/illustrations/make-before-break-changeover-contact.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pub-symbol-misc-switches","title":"AutoCAD Electrical: Level, flow, keyed and measurement switches","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-1FB94435-C954-4479-BD97-25796DB8F728.htm","type":"cad-reference","scope":"Public vendor catalogue naming and functional variants. Vendor block names are not IEC identifiers. Linked for reference; no graphics or CAD files are redistributed.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic."}]}