Isolator
Disconnector
A switching device providing an electrical isolation function.
SLD / Schematic
Symbols · CB
Circuit breaker
A switching device that can interrupt a circuit, with specified fault-interruption capability.
SLD / Schematic · CB
What it represents
A circuit-breaker representation identifies a device capable of interrupting its circuit under the operating conditions for which it is rated. The drawing should connect that device to its equipment identification, protection arrangement and control information. The graphical mark alone does not establish the current rating, breaking capacity or trip settings.
Breaker representations vary between drawing conventions and may include qualifiers for operating mechanism or protection. An SLD gives system position and major connections. A control schematic expands the close, trip, indication and auxiliary-contact circuits.
How to read it
- Read device state according to the drawing legend, rather than assuming every open-looking mark means equipment is currently open.
- Keep the equipment tag, graphical symbol and ANSI device-function number 52 distinct.
Information to show or reference
- Reference the voltage, current and breaking-capacity data.
- Identify poles and the applicable protection arrangement.
- Link the control circuit and auxiliary contacts.
A distinction that matters
A disconnector provides isolation; it is not automatically a fault-interrupting circuit breaker. Check published device capabilities.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Circuit-breaker symbol variants
Public breaker categories and qualifying features.
Fundamental characteristics of a circuit-breaker
Manufacturer explanation of circuit-breaker characteristics.
Public reference table of ANSI device-function numbers
Public reference for device-function number 52.
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. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
Explore related references
LBS
Load-break switch
A switch with a specified capability to make and break normal load current.
SLD / Schematic
52
AC circuit breaker
The device-function number identifying an AC circuit breaker.
Protection functions
NO
Normally open contact
A contact shown open in the normal state defined for its device.
Schematic
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