{"schemaVersion":1,"slug":"iec-pushbutton-contact-mushroom-head-normally-closed-latching-key-operated","name":"IEC pushbutton contact: mushroom head normally closed latching, key operated","kind":"symbol","abbreviation":"PB","aliases":["HPB12S82","VPB12S82","pushbutton contact Mushroom Head Normally Closed Latching, Key Operated"],"category":"control-circuits","drawingTypes":["Schematic"],"referenceFamilies":["IEC","Manufacturer"],"summary":"Pushbutton contact form: Mushroom Head Normally Closed Latching, Key Operated.","description":["A pushbutton translates a person pressing an operator into a change of electrical contact state. The operator form and the contact state are separate pieces of information, so a mushroom head can operate either a normally-open or a normally-closed contact. This entry identifies the mushroom head normally closed latching, key operated form in the publisher's IEC-context family.","On a machine control sheet, this form lets the reader distinguish the physical button action from the contact used by the controller. Link every contact block to the same operator tag, including a separate indication lamp when fitted. The normally-closed designation starts with a conducting output or closed contact in the documented reference condition; operation changes that state. The retained operator requires the documented key action for release. Key availability is an operating constraint and does not by itself create an electrical interlock.","The head shape and contact drawing do not establish a safety category, contact rating or emergency-stop suitability. Direct opening, reset behaviour and the selected assembly must be confirmed from its documentation."],"readingNotes":["The normally-closed designation starts with a conducting output or closed contact in the documented reference condition; operation changes that state.","The retained operator requires the documented key action for release. Key availability is an operating constraint and does not by itself create an electrical interlock.","The head shape and contact drawing do not establish a safety category, contact rating or emergency-stop suitability. Direct opening, reset behaviour and the selected assembly must be confirmed from its documentation."],"drawingChecklist":["Identify the operator and each associated contact block.","State the contact state before the operator is pressed.","Show the release or return action and any independent lamp supply."],"distinction":"This entry adds the mushroom head normally closed latching, key operated detail to the broader pushbutton contact family. The head shape and contact drawing do not establish a safety category, contact rating or emergency-stop suitability. Direct opening, reset behaviour and the selected assembly must be confirmed from its documentation.","facts":[{"label":"Drawing form","value":"Mushroom Head Normally Closed Latching, Key Operated"},{"label":"Public vendor block names","value":"HPB12S82 / VPB12S82. Autodesk identifiers, not standards database IDs."},{"label":"Drawing purpose","value":"pushbutton contact"},{"label":"Graphic scope","value":"Independently authored educational illustration; not certified standard geometry, a terminal pinout or a product footprint."}],"references":[{"sourceId":"autodesk-pushbuttons","relevance":"Public Push Buttons table explicitly lists HPB12S82 / VPB12S82 with this operating or connection form. Vendor graphics are linked, not copied."}],"related":["pushbutton-no","pushbutton-nc","emergency-stop"],"artwork":"s28-iec-pushbutton-contact-mushroom-head-normally-closed-latching-key-operated","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"Mushroom Head Normally Closed Latching, Key Operated","reference":"Autodesk IEC-60617 Symbol Preview: Push Buttons, HPB12S82 / VPB12S82. This identifies the publisher's library context; exact IEC graphics and database identities are not asserted."},"plainEnglish":{"title":"What does IEC pushbutton contact: mushroom head normally closed latching, key operated mean?","introduction":"A pushbutton translates a person pressing an operator into a change of electrical contact state. The operator form and the contact state are separate pieces of information, so a mushroom head can operate either a normally-open or a normally-closed contact. This entry identifies the mushroom head normally closed latching, key operated form in the publisher's IEC-context family.","example":"On a machine control sheet, this form lets the reader distinguish the physical button action from the contact used by the controller. Link every contact block to the same operator tag, including a separate indication lamp when fitted. The normally-closed designation starts with a conducting output or closed contact in the documented reference condition; operation changes that state. The retained operator requires the documented key action for release. Key availability is an operating constraint and does not by itself create an electrical interlock.","drawings":"The head shape and contact drawing do not establish a safety category, contact rating or emergency-stop suitability. Direct opening, reset behaviour and the selected assembly must be confirmed from its documentation.","terms":[{"name":"Normally open / normally closed","meaning":"The contact state in the normal condition defined for the drawing."},{"name":"Signal","meaning":"Electrical information passed between devices, rather than necessarily the main power supply."},{"name":"Rating","meaning":"A value stating the conditions for which equipment is specified."}],"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":"Pushbutton contact and actuator variants","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-9E8890C7-7176-47DD-8700-E02A16C1670E.htm"}],"detail":"Pushbutton contact form: Mushroom Head Normally Closed Latching, Key Operated. This entry adds the mushroom head normally closed latching, key operated detail to the broader pushbutton contact family. The head shape and contact drawing do not establish a safety category, contact rating or emergency-stop suitability. Direct opening, reset behaviour and the selected assembly must be confirmed from its documentation.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/iec-pushbutton-contact-mushroom-head-normally-closed-latching-key-operated","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/iec-pushbutton-contact-mushroom-head-normally-closed-latching-key-operated.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"autodesk-pushbuttons","title":"Pushbutton contact and actuator variants","publisher":"Autodesk","url":"https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-9E8890C7-7176-47DD-8700-E02A16C1670E.htm","type":"cad-reference","scope":"Momentary and latching pushbuttons, normal contact states and mushroom actuators.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public Push Buttons table explicitly lists HPB12S82 / VPB12S82 with this operating or connection form. Vendor graphics are linked, not copied."}]}