{"schemaVersion":1,"slug":"residual-voltage-monitoring-relay","name":"Residual-voltage monitoring relay","kind":"symbol","abbreviation":"U RES","aliases":["HCR1F38","VCR1F38"],"category":"measurement-protection","drawingTypes":["SLD","Schematic"],"referenceFamilies":["Manufacturer"],"summary":"A residual-voltage relay responds to the specified residual-voltage measurement.","description":["A residual-voltage relay responds to the specified residual-voltage measurement. Its drawing needs the voltage-transformer connection and the input quantity definition."],"readingNotes":["Check the measurement circuit that produces the residual voltage.","The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation."],"drawingChecklist":["Show VT connection","State residual input scaling","Reference operating threshold"],"distinction":"Residual voltage is different from phase-to-neutral voltage at an arbitrary single phase.","facts":[{"label":"Drawing role","value":"Monitoring element"},{"label":"Representation scope","value":"Functional concept; not an official standard graphic or a product footprint"},{"label":"Public vendor block reference","value":"HCR1F38, VCR1F38 (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-voltage-relays","relevance":"Public documentation of this equipment function or named vendor variant; the illustration is independently authored and is not the source graphic."}],"related":["current-transformer","relay-coil"],"artwork":"edu-residual-voltage-monitoring-relay","publishedOn":"2026-10-13","updatedOn":"2026-10-13","provenance":"independent-public-research","url":"https://eloragrid.ai/symbols/residual-voltage-monitoring-relay","illustration":{"url":"https://eloragrid.ai/library/illustrations/residual-voltage-monitoring-relay.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-voltage-relays","title":"AutoCAD Electrical: Voltage monitoring relays","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-5296749E-9336-4B07-9956-160963D6C848.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."}]}