# ANSI/IEEE Manually unlatched NC contact form Canonical URL: https://eloragrid.ai/symbols/ansi-manually-unlatched-nc-contact Publisher: Elora Grid Updated: 2026-10-28 Lookup label: NC UNLATCH Drawing use: Schematic Reference families: IEEE / ANSI, Manufacturer ## Symbol convention Convention: IEEE / ANSI Form: With Mechanical Block and Manual Unlatching Autodesk IEEE Symbol Preview: Relays and Contacts, block HCR2221F. Matching functional counterpart linked separately. Independently drawn educational geometry; not a certified IEEE glyph or database identifier. Related representation: [Manually unlatched NC contact](https://eloragrid.ai/symbols/manually-unlatched-nc-contact) IEEE-library form of manually unlatched nc contact: a manually unlatched NC contact has a mechanical retained state and a documented manual release. ## In plain English ### What does ANSI/IEEE Manually unlatched NC contact form mean? This reference locates manually unlatched nc contact in Autodesk's IEEE-oriented relays and contacts family. A manually unlatched normally closed contact has a mechanical retained state and a documented manual release. Its reference state is closed but the retained operated position must be stated. The public library uses HCR2221F for its horizontal representation; this is a vendor block name, not an IEEE standards symbol number. ### A simple example Trace the measured quantity or initiating control signal separately from the output contacts. The device tag links the sensing or operating element to the controlled circuit; settings, reset behaviour and the actual terminal arrangement belong in the selected equipment documentation. ### What the drawings help you do Confirm which contact position the mechanism retains. A mechanical retention marker must not be confused with a delayed-return timer marker. The linked functional counterpart explains the same operating role in its own drawing context; agreement of every detailed convention mark is not asserted. ### This particular reference IEEE-library form of manually unlatched nc contact: a manually unlatched normally closed contact has a mechanical retained state and a documented manual release. A mechanical retention marker must not be confused with a delayed-return timer marker. ### Terms - Normally open / normally closed: The contact state in the normal condition defined for the drawing. - Coil: A wound conductor that can produce a magnetic field when energised. - Terminal: An identified point where a conductor connects. Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram. - [Autodesk IEEE Symbol Preview — Relays and Contacts](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-F8EAC387-53CF-45FE-BE6A-C0C8FB3C1B22.htm) ## What it represents This reference locates manually unlatched nc contact in Autodesk's IEEE-oriented relays and contacts family. A manually unlatched NC contact has a mechanical retained state and a documented manual release. Its reference state is closed but the retained operated position must be stated. The public library uses HCR2221F for its horizontal representation; this is a vendor block name, not an IEEE standards symbol number. Trace the measured quantity or initiating control signal separately from the output contacts. The device tag links the sensing or operating element to the controlled circuit; settings, reset behaviour and the actual terminal arrangement belong in the selected equipment documentation. Confirm which contact position the mechanism retains. A mechanical retention marker must not be confused with a delayed-return timer marker. The linked functional counterpart explains the same operating role in its own drawing context; agreement of every detailed convention mark is not asserted. ## How to read it - Confirm which contact position the mechanism retains. - The preview is an original explanation of this function. Match the actual drawing convention to its legend and the selected equipment documentation. ## Information to show or reference - State reference and retained states - Identify manual release - Link associated device ## Important distinction A mechanical retention marker must not be confused with a delayed-return timer marker. ## Facts - Convention evidence: Autodesk IEEE Symbol Preview: Relays and Contacts; published form: With Mechanical Block and Manual Unlatching. - Public vendor block: HCR2221F. Vendor library token, not an IEEE symbol number. - Drawing role: Contact state - Identifier status: 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. - Artwork scope: Original educational geometry. Exact standard graphics, product ratings and terminal pinouts are not certified. ## Public references - [Autodesk IEEE Symbol Preview — Relays and Contacts](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-F8EAC387-53CF-45FE-BE6A-C0C8FB3C1B22.htm) — Autodesk. Public IEEE-oriented Relays and Contacts table explicitly lists HCR2221F as With Mechanical Block and Manual Unlatching. This supports the vendor convention context, not reproduction of the publisher graphic. ## Graphic scope Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.