{"schemaVersion":1,"slug":"iec-pen-conductor-mark","name":"PEN conductor mark","kind":"symbol","abbreviation":"PEN","aliases":["combined neutral and earth mark","CNE conductor mark","PEN tick"],"category":"connections-wiring","drawingTypes":["SLD","Schematic"],"referenceFamilies":["IEC"],"summary":"A mark identifying a combined protective and neutral conductor, as used in TN-C sections of a supply.","description":["The PEN mark identifies one conductor that performs both the protective and neutral functions. It appears in TN-C and TN-C-S arrangements, typically between the supply transformer and the main switchboard, where the PEN is later separated into N and PE at a defined point.","A PEN conductor must not be switched or isolated on its own, and once separated into N and PE the two must not be rejoined downstream. A drawing that shows a PEN mark should therefore also show the separation point clearly. The mark says nothing about minimum conductor size, which local wiring rules set for PEN conductors."],"readingNotes":["Find the point where the PEN is split into N and PE.","Check that no switching device opens the PEN conductor alone."],"drawingChecklist":["Show the PEN to N and PE separation point.","Avoid single-pole switching of the PEN.","Confirm PEN sizing against the applicable wiring rules."],"distinction":"A PEN conductor combines N and PE functions; a neutral mark shows a conductor that has no protective role.","facts":[{"label":"Graphic cue","value":"Combined neutral and earth mark on one stroke"},{"label":"Letter code","value":"PEN"},{"label":"Scheme context","value":"TN-C and TN-C-S sections"},{"label":"Preview","value":"Original educational illustration; consult the publisher and applicable standard for the exact graphic"}],"references":[{"sourceId":"s28-eig-earthing-schemes","relevance":"Public installation-guide definitions of TN-C and TN-C-S schemes."},{"sourceId":"s28-eig-earthing-connections","relevance":"Public guide to earthing connection elements."}],"related":["iec-neutral-conductor-mark","iec-protective-conductor-mark","iec-men-link"],"artwork":"s28-iec-pen-conductor-mark","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"PEN conductor identification on a conductor group","reference":"Independent IEC-context illustration; not certified IEC geometry."},"plainEnglish":{"title":"What does PEN conductor mark mean?","introduction":"The PEN mark identifies one conductor that performs both the protective and neutral functions. It appears in TN-C and TN-C-S arrangements, typically between the supply transformer and the main switchboard, where the PEN is later separated into N and PE at a defined point.","example":"A PEN conductor must not be switched or isolated on its own, and once separated into N and PE the two must not be rejoined downstream. A drawing that shows a PEN mark should therefore also show the separation point clearly. The mark says nothing about minimum conductor size, which local wiring rules set for PEN conductors.","drawings":"Find the point where the PEN is split into N and PE. Check that no switching device opens the PEN conductor alone. A PEN conductor combines N and PE functions; a neutral mark shows a conductor that has no protective role.","terms":[{"name":"Winding","meaning":"A coil of conductor inside an electrical machine or transformer."},{"name":"Rating","meaning":"A value stating the conditions for which equipment is specified."},{"name":"Schematic","meaning":"A drawing showing function and connections rather than physical appearance."}],"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":"Definition of standardised earthing schemes","url":"https://www.electrical-installation.org/enwiki/Definition_of_standardised_earthing_schemes"},{"label":"Earthing connections","url":"https://www.electrical-installation.org/enwiki/Earthing_connections"}],"detail":"A mark identifying a combined protective and neutral conductor, as used in TN-C sections of a supply. A PEN conductor combines N and PE functions; a neutral mark shows a conductor that has no protective role.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/iec-pen-conductor-mark","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/iec-pen-conductor-mark.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"s28-eig-earthing-schemes","title":"Definition of standardised earthing schemes","publisher":"Schneider Electric, Electrical Installation Guide","url":"https://www.electrical-installation.org/enwiki/Definition_of_standardised_earthing_schemes","type":"manufacturer","scope":"TT, TN (including TN-C and TN-C-S with PEN conductors) and IT system earthing arrangements.","checkedOn":"2026-10-28","reuse":"link-only","relevance":"Public installation-guide definitions of TN-C and TN-C-S schemes."},{"id":"s28-eig-earthing-connections","title":"Earthing connections","publisher":"Schneider Electric, Electrical Installation Guide","url":"https://www.electrical-installation.org/enwiki/Earthing_connections","type":"manufacturer","scope":"Definitions of earth electrode, main earthing terminal, removable test link and bonding conductors in an installation earthing arrangement.","checkedOn":"2026-10-28","reuse":"link-only","relevance":"Public guide to earthing connection elements."}]}