LBS
Load-break switch
A switch with a specified capability to make and break normal load current.
SLD / Schematic
Symbols · Isolator
Disconnector
A switching device providing an electrical isolation function.
SLD / Schematic · Isolator
What it represents
A disconnector, often called an isolator, provides an isolation function in an electrical circuit. Its representation should be read with the drawing legend and the selected device specification. Do not infer load-breaking or fault-interruption capability simply because a drawing contains a switch-like mark.
In a switchgear SLD the disconnector may appear next to a breaker, earthing switch or bus section. Control drawings can also show position indications and interlocking. The main-circuit representation and the auxiliary indications describe different parts of the equipment.
How to read it
- Identify which circuit segment is isolated by the device.
- Distinguish the main switching function from its auxiliary position contacts.
Information to show or reference
- Link the selected device and its isolation capability.
- Reference the position indication and interlock documentation.
- Show associated earthing arrangements where applicable.
A distinction that matters
A load-break switch has a specified load-switching capability. A disconnector designation alone does not establish that capability.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Elementary switching devices
Manufacturer explanation of disconnector and load-breaking functions.
Secondary-distribution switchgear and ring main units
Public secondary-distribution switchgear context.
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
CB
Circuit breaker
A switching device that can interrupt a circuit, with specified fault-interruption capability.
SLD / Schematic
ES
Earthing switch
A switch used to connect an identified circuit section to earth.
SLD / Schematic
89
Line switch
The device-function number used for a line-switching or disconnecting device in its documented application.
Protection functions
Put the reference into a drawing workflow.
Elora Grid helps electrical teams work with drawings, specifications and equipment information. Explore the drafting workflow or join the early-access waitlist.