# Switchroom external lighting command interface Canonical URL: https://eloragrid.ai/symbols/switchroom-external-lighting-command-interface Publisher: Elora Grid Updated: 2026-11-03 Lookup label: SELCI Drawing use: Schematic Reference families: Manufacturer Representation: Functional block Installation focus: switchrooms Input: External lighting request Output: Approach lighting command Links the room controls to the assigned external approach-lighting circuit. ## In plain English ### What this block does Links the room controls to the assigned external approach-lighting circuit. ### A simple example In a switchroom, a normal lighting branch may be switched locally while the specified emergency luminaires remain connected to their own backed-up or integral supply. For this reference, the drawing identifies “External lighting request” at the input and “Approach lighting command” at the output. The circuit boundary must be named. ### What the drawings help you do Start at the named input: External lighting request. Identify its source device or document and the state represented on the drawing. Follow the named output: Approach lighting command. Cross-reference its destination and separate the command from confirmation that the equipment responded. ### Terms - Input: External lighting request - Output: Approach lighting command - Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections. Concept diagram: External lighting request → SELCI → Approach lighting command A reading guide. The entry's original illustration and input/output facts describe this application. - [Indoor substation: lighting, fire and auxiliary services](https://www.electrical-installation.org/enwiki/Indoor_substation) ## What it represents Links the room controls to the assigned external approach-lighting circuit. Lighting and access interfaces coordinate the electrical-room service circuits and their supervision. Normal lighting, emergency illumination and access indication have different power sources and purposes. In a switchroom, a normal lighting branch may be switched locally while the specified emergency luminaires remain connected to their own backed-up or integral supply. For this reference, the drawing identifies “External lighting request” at the input and “Approach lighting command” at the output. The circuit boundary must be named. Identify the lighting supply type, controlled circuit and the meaning of any test or failure output. A drawing symbol does not establish illumination levels, emergency duration or an approved egress arrangement. The functional block is an independent explanation of this named application. Equipment-specific ratings, terminal connections and operating conditions must be established in the project documentation. ## How to read it - Start at the named input: External lighting request. Identify its source device or document and the state represented on the drawing. - Follow the named output: Approach lighting command. Cross-reference its destination and separate the command from confirmation that the equipment responded. - The circuit boundary must be named. - Identify the lighting supply type, controlled circuit and the meaning of any test or failure output. A drawing symbol does not establish illumination levels, emergency duration or an approved egress arrangement. ## Information to show or reference - Label the source and connection reference for external lighting request. - Identify the destination and defined state of approach lighting command. - Record the equipment or control-document revision supporting this functional block. - Check this application limit in the project design: The circuit boundary must be named. ## Important distinction The circuit boundary must be named. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram. ## Facts - Representation: Functional block - Installation focus: Switchrooms - Input / boundary: External lighting request - Output / connection: Approach lighting command - Lookup label: SELCI is a library lookup label, not a standard device designation. ## Public references - [Indoor substation: lighting, fire and auxiliary services](https://www.electrical-installation.org/enwiki/Indoor_substation) — Schneider Electric. Public technical context for switchroom lighting and access interfaces. Lighting, emergency lighting, fire provisions and substation auxiliary services. Original cause-and-effect examples require project design. The application text and educational graphic are independently authored; the publisher does not certify this representation. ## Graphic scope Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.