# Breaker open-trip seal-in contact Canonical URL: https://eloragrid.ai/symbols/breaker-open-trip-seal-in-contact Publisher: Elora Grid Updated: 2026-11-03 Lookup label: BOSC Drawing use: Schematic Reference families: Manufacturer Representation: Functional block Installation focus: switchgear Input: Trip initiation and position Output: Sustained trip request Sustains a trip request through its designed seal-in path until the specified feedback terminates it. ## In plain English ### What this block does Sustains a trip request through its designed seal-in path until the specified feedback terminates it. ### A simple example In a switchgear incomer panel, a protection relay requests opening and an auxiliary contact reports the resulting breaker position. A second trip path can have its own supply and wiring so that a single wiring fault does not remove both paths. For this reference, the drawing identifies “Trip initiation and position” at the input and “Sustained trip request” at the output. The release condition must be drawn explicitly. ### What the drawings help you do Start at the named input: Trip initiation and position. Identify its source device or document and the state represented on the drawing. Follow the named output: Sustained trip request. Cross-reference its destination and separate the command from confirmation that the equipment responded. ### Terms - Input: Trip initiation and position - Output: Sustained trip request - Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections. Concept diagram: Trip initiation and position → BOSC → Sustained trip request A reading guide. The entry's original illustration and input/output facts describe this application. - [Masterclad medium-voltage switchgear: circuit-breaker section interlocks](https://productinfo.se.com/masterclad_mv_switchgear_ib/6055-30-masterclad-15kv-mv-switchgear-ib/English/6055-30%20Masterclad%20MV%20Switchgear%20Indoor%20%28bookmap%29_DD00646805.xml/%24/Section6-CircuitBreakerSectionInter-58DD6EC7) ## What it represents Sustains a trip request through its designed seal-in path until the specified feedback terminates it. A trip circuit carries an opening request from a control or protection device to the breaker operating mechanism. The opening command, the coil supply and the evidence that the breaker opened are separate parts of the drawing. In a switchgear incomer panel, a protection relay requests opening and an auxiliary contact reports the resulting breaker position. A second trip path can have its own supply and wiring so that a single wiring fault does not remove both paths. For this reference, the drawing identifies “Trip initiation and position” at the input and “Sustained trip request” at the output. The release condition must be drawn explicitly. Trace the initiating contact, protective fuse, trip coil, return conductor and feedback independently. Identify which elements are shared between redundant paths. The diagram explains the intended command path; coil ratings and terminal numbers come from the selected breaker. 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: Trip initiation and position. Identify its source device or document and the state represented on the drawing. - Follow the named output: Sustained trip request. Cross-reference its destination and separate the command from confirmation that the equipment responded. - The release condition must be drawn explicitly. - Trace the initiating contact, protective fuse, trip coil, return conductor and feedback independently. Identify which elements are shared between redundant paths. The diagram explains the intended command path; coil ratings and terminal numbers come from the selected breaker. ## Information to show or reference - Label the source and connection reference for trip initiation and position. - Identify the destination and defined state of sustained trip request. - Record the equipment or control-document revision supporting this functional block. - Check this application limit in the project design: The release condition must be drawn explicitly. ## Important distinction The release condition must be drawn explicitly. 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: Switchgear - Input / boundary: Trip initiation and position - Output / connection: Sustained trip request - Lookup label: BOSC is a library lookup label, not a standard device designation. ## Public references - [Masterclad medium-voltage switchgear: circuit-breaker section interlocks](https://productinfo.se.com/masterclad_mv_switchgear_ib/6055-30-masterclad-15kv-mv-switchgear-ib/English/6055-30%20Masterclad%20MV%20Switchgear%20Indoor%20%28bookmap%29_DD00646805.xml/%24/Section6-CircuitBreakerSectionInter-58DD6EC7) — Schneider Electric. Public technical context for breaker trip circuits. Breaker control, mechanism, position contacts, racking interlocks and test interfaces. 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.