{"schemaVersion":1,"slug":"arc-flash-point-sensor","name":"Arc-flash point light sensor","kind":"symbol","abbreviation":"AF","aliases":["arc flash point sensor","arc detection light sensor"],"category":"measurement-protection","drawingTypes":["SLD","Schematic"],"referenceFamilies":["Manufacturer"],"summary":"Light sensor in a switchgear compartment that detects the flash of an internal arc and signals an arc-flash relay.","description":["A point light sensor is mounted inside a switchgear compartment, such as a breaker or cable compartment, and detects the intense light of an internal arc. It is wired or fibre-connected to an arc-flash relay that usually also checks for overcurrent before tripping, so light alone from an external source does not cause a trip.","The drawing should show which compartment each sensor watches, because the trip zone depends on it. The symbol does not show sensitivity, field of view or the self-supervision used to detect a disconnected sensor."],"readingNotes":["Identify the compartment each sensor covers.","Check whether trip needs light plus overcurrent."],"drawingChecklist":["Locate each sensor by compartment","Show connection to the arc relay","State trip logic"],"distinction":"A point sensor covers one compartment; a fibre loop sensor covers a long area such as a busbar run.","facts":[{"label":"Detected quantity","value":"Light from an internal arc"},{"label":"Typical logic","value":"Light combined with overcurrent"},{"label":"Preview","value":"Functional illustration of the device role; not a product footprint or certified standard graphic"}],"references":[{"sourceId":"s28-sel-arc-flash-fibre","relevance":"Public manufacturer page describing point and fibre arc-flash light sensing."}],"related":["arc-flash-fibre-loop-sensor","numerical-protection-relay","switchgear-panel"],"artwork":"s28-arc-flash-point-sensor","publishedOn":"2026-10-28","updatedOn":"2026-10-28","provenance":"independent-public-research","plainEnglish":{"title":"What does Arc-flash point light sensor mean?","introduction":"A point light sensor is mounted inside a switchgear compartment, such as a breaker or cable compartment, and detects the intense light of an internal arc. It is wired or fibre-connected to an arc-flash relay that usually also checks for overcurrent before tripping, so light alone from an external source does not cause a trip.","example":"The drawing should show which compartment each sensor watches, because the trip zone depends on it. The symbol does not show sensitivity, field of view or the self-supervision used to detect a disconnected sensor.","drawings":"Identify the compartment each sensor covers. Check whether trip needs light plus overcurrent. A point sensor covers one compartment; a fibre loop sensor covers a long area such as a busbar run.","terms":[{"name":"Coil","meaning":"A wound conductor that can produce a magnetic field when energised."},{"name":"Terminal","meaning":"An identified point where a conductor connects."},{"name":"Signal","meaning":"Electrical information passed between devices, rather than necessarily the main power supply."}],"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":"SEL-C804 multimode arc-flash detection fibre-optic cables","url":"https://selinc.com/products/c804/"}],"detail":"Light sensor in a switchgear compartment that detects the flash of an internal arc and signals an arc-flash relay. A point sensor covers one compartment; a fibre loop sensor covers a long area such as a busbar run.","profileId":"reviewed-symbol-20261028"},"url":"https://eloragrid.ai/symbols/arc-flash-point-sensor","illustration":{"url":"https://eloragrid.ai/tools/electrical-library/illustrations/arc-flash-point-sensor.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"s28-sel-arc-flash-fibre","title":"SEL-C804 multimode arc-flash detection fibre-optic cables","publisher":"Schweitzer Engineering Laboratories","url":"https://selinc.com/products/c804/","type":"manufacturer","scope":"Public product page describing point and fibre arc-flash light sensors used with protection relays.","checkedOn":"2026-10-28","reuse":"link-only","relevance":"Public manufacturer page describing point and fibre arc-flash light sensing."}]}