SD
Switch-disconnector
A switch-disconnector combines operational switching with an isolation function.
SLD / Schematic
IEC · ISO
Local isolator plan mark
Plan mark for a local isolating switch placed beside fixed equipment for safe maintenance.
In plain English
What does Local isolator plan mark mean?
Local isolators are placed within sight of motors, air-conditioning units, pumps and fans so maintenance staff can isolate and lock the supply. Plans draw a small switch box with an isolation mark or the letters ISO beside the equipment it serves, sometimes with a lock indication.
A simple example
The mark tells the installer to provide a device rated for isolation and, where required, lockable in the off position. Pole count follows the supply: three-pole or four-pole for three-phase plant. It does not specify utilisation category or whether the device can switch motor load. Those are in the schedule.
What the drawings help you do
Check it is within sight of the equipment. Confirm pole count and locking provision. A switched socket outlet is not an isolator; this plan mark designates an isolation-rated device.
This particular reference
Plan mark for a local isolating switch placed beside fixed equipment for safe maintenance. A switched socket outlet is not an isolator; this plan mark designates an isolation-rated device.
- Phase
- One of the related AC waveforms in a power system.
- Rating
- A value stating the conditions for which equipment is specified.
- Schematic
- A drawing showing function and connections rather than physical appearance.
Read the source: IEC graphical symbols for diagrams · Elementary switching devices
IEC · Isolating switch, installation plan
IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.
Shown as an independently authored educational illustration. Use the cited publication and drawing legend to verify the required drafting form.
GA · ISO
What it represents
Local isolators are placed within sight of motors, air-conditioning units, pumps and fans so maintenance staff can isolate and lock the supply. Plans draw a small switch box with an isolation mark or the letters ISO beside the equipment it serves, sometimes with a lock indication.
The mark tells the installer to provide a device rated for isolation and, where required, lockable in the off position. Pole count follows the supply: three-pole or four-pole for three-phase plant. It does not specify utilisation category or whether the device can switch motor load. Those are in the schedule.
How to read it
- Check it is within sight of the equipment.
- Confirm pole count and locking provision.
Information to show or reference
- State poles and rating.
- State lockability.
- Tag the equipment served.
A distinction that matters
A switched socket outlet is not an isolator; this plan mark designates an isolation-rated device.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
IEC graphical symbols for diagrams
IEC graphical symbol context; independently drawn here.
Elementary switching devices
Explains the isolation function and its requirements.
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
SD LOCK
Lockable switch-disconnector
A lockable switch-disconnector combines an isolation-capable switching device with a documented locking provision.
SLD / Schematic
S2P
Two-pole one-way switch plan mark
Plan mark for a one-way switch that breaks both line and neutral, drawn with two ticks on the stroke.
IEC
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