{"schemaVersion":1,"slug":"iec-pushbutton-contact-mushroom-head-normally-closed-latching","name":"IEC pushbutton contact: mushroom head normally closed latching","kind":"symbol","abbreviation":"PB","aliases":["HPB12ML","VPB12ML","pushbutton contact Mushroom Head Normally Closed Latching"],"category":"control-circuits","drawingTypes":["Schematic"],"referenceFamilies":["IEC","Manufacturer"],"summary":"Pushbutton contact form: Mushroom Head Normally Closed Latching.","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 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 mechanism keeps its operated position until its specified release action; releasing hand pressure alone is insufficient.","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 mechanism keeps its operated position until its specified release action; releasing hand pressure alone is insufficient.","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 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"},{"label":"Public vendor block names","value":"HPB12ML / VPB12ML. 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 HPB12ML / VPB12ML 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","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"Mushroom Head Normally Closed Latching","reference":"Autodesk IEC-60617 Symbol Preview: Push Buttons, HPB12ML / VPB12ML. 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 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 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 mechanism keeps its operated position until its specified release action; releasing hand pressure alone is insufficient.","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. This entry adds the mushroom head normally closed latching 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","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/iec-pushbutton-contact-mushroom-head-normally-closed-latching.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 HPB12ML / VPB12ML with this operating or connection form. Vendor graphics are linked, not copied."}]}