{"schemaVersion":1,"slug":"iec-maintained-emergency-luminaire","name":"Maintained emergency luminaire plan mark","kind":"symbol","abbreviation":"EM-M","aliases":["maintained emergency light","emergency luminaire, maintained","M3 luminaire"],"category":"installation-communications","drawingTypes":["GA"],"referenceFamilies":["IEC"],"summary":"Plan mark for an emergency luminaire whose lamp is lit at all times and stays lit on supply failure.","description":["A maintained emergency luminaire operates as a normal light and continues on battery when the normal supply fails. Plans usually draw the luminaire mark with an emergency indicator, such as a filled segment or a letter E, plus an M or maintained tag.","Maintained operation is common in places of assembly, cinemas and some exit signs. The fitting needs both a switched supply for normal operation (where switched maintained) and an unswitched permanent supply to charge the battery and sense failure.","The tag does not give the duration. Emergency duration (for example 1 h or 3 h) should appear in the schedule or legend."],"readingNotes":["Look for the M tag or legend key.","Check the unswitched supply is shown."],"drawingChecklist":["State duration.","Provide permanent unswitched supply.","Mark test facility or self-test type."],"distinction":"A non-maintained emergency luminaire lights only on supply failure; the maintained form is lit continuously.","facts":[{"label":"Operation","value":"Lit in normal and emergency modes"},{"label":"Supply","value":"Permanent live for charging and sensing"},{"label":"Exact standard graphic","value":"Not reproduced here; confirm the form against IEC 60617 and the project legend"}],"references":[{"sourceId":"iec-diagrams","relevance":"IEC graphical symbol context for installation plans; independently drawn here."},{"sourceId":"pub-object-engineering-design","relevance":"Installation design methodology covering lighting circuits and final distribution."}],"related":["iec-non-maintained-emergency-luminaire","iec-exit-sign-luminaire"],"artwork":"s28-iec-maintained-emergency-luminaire","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","symbolVariant":{"convention":"IEC","form":"Emergency luminaire, maintained","reference":"IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier."},"plainEnglish":{"title":"What does Maintained emergency luminaire plan mark mean?","introduction":"A maintained emergency luminaire operates as a normal light and continues on battery when the normal supply fails. Plans usually draw the luminaire mark with an emergency indicator, such as a filled segment or a letter E, plus an M or maintained tag.","example":"Maintained operation is common in places of assembly, cinemas and some exit signs. The fitting needs both a switched supply for normal operation (where switched maintained) and an unswitched permanent supply to charge the battery and sense failure.","drawings":"The tag does not give the duration. Emergency duration (for example 1 h or 3 h) should appear in the schedule or legend.","terms":[{"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":"IEC graphical symbols for diagrams","url":"https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/"},{"label":"Electrical installation design methodology and references","url":"https://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_design"}],"detail":"Plan mark for an emergency luminaire whose lamp is lit at all times and stays lit on supply failure. A non-maintained emergency luminaire lights only on supply failure; the maintained form is lit continuously.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/iec-maintained-emergency-luminaire","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/iec-maintained-emergency-luminaire.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"iec-diagrams","title":"IEC graphical symbols for diagrams","publisher":"IEC","url":"https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/","type":"standard","scope":"IEC 60617 and related symbol-design publications. Full database access requires a subscription.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"IEC graphical symbol context for installation plans; independently drawn here."},{"id":"pub-object-engineering-design","title":"Electrical installation design methodology and references","publisher":"Schneider Electric — Electrical Installation Guide","url":"https://www.electrical-installation.org/enwiki/General_rules_of_electrical_installation_design","type":"manufacturer","scope":"Public design context. No universal working clearance, equipment dimension or project compliance conclusion is asserted.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Installation design methodology covering lighting circuits and final distribution."}]}