CB
Circuit breaker
A switching device that can interrupt a circuit, with specified fault-interruption capability.
SLD / Schematic
Functional block · MEP
Manual emergency-trip path
Functional block · Switchgear
An independently authored application reference. The drawing shows the named function or circuit relationship; use the project legend and selected equipment documentation for its drafting form and connections.
Browse this installation focusIn plain English
What this block does
Shows the hardwired opening request issued by the designated emergency control station.
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 “Emergency control contact” at the input and “Breaker opening request” at the output. Opening this breaker may leave other sources connected.
What the drawings help you do
Start at the named input: Emergency control contact. Identify its source device or document and the state represented on the drawing. Follow the named output: Breaker opening request. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Input
- Emergency control contact
- Output
- Breaker opening request
- Application reference
- An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.
Read the source: Masterclad medium-voltage switchgear: circuit-breaker section interlocks
Schematic · MEP
What it represents
Shows the hardwired opening request issued by the designated emergency control station. 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 “Emergency control contact” at the input and “Breaker opening request” at the output. Opening this breaker may leave other sources connected.
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: Emergency control contact. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Breaker opening request. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Opening this breaker may leave other sources connected.
- 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 emergency control contact.
- Identify the destination and defined state of breaker opening request.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Opening this breaker may leave other sources connected.
A distinction that matters
Opening this breaker may leave other sources connected. 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.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Masterclad medium-voltage switchgear: circuit-breaker section interlocks
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.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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