SS
Selector switch
An operator switch selecting between documented control positions.
Schematic
Protection functions · 10
Unit sequence switch
Selects or determines the order in which multiple units enter an operating sequence.
SLD / Schematic · 10
What it represents
Selects or determines the order in which multiple units enter an operating sequence.
In a drafting package, connect this reference to the selected unit order and selector positions. The associated drawing should trace the unit-specific start-permission circuits; the number identifies the role and does not specify the terminal arrangement, ratings or operating settings.
How to read it
- Identify the selected unit order and selector positions.
- Trace the unit-specific start-permission circuits.
Information to show or reference
- Label the selected unit order and selector positions.
- Cross-reference the unit-specific start-permission circuits.
- Identify the device tag, manual revision and logic drawing that define this implementation.
A distinction that matters
Unit ordering differs from device 34, which sequences the operations inside a unit or system.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
ANSI device-number and suffix reference table
Public manufacturer number/name association. Drafting explanations are independently written.
IEEE C37.2-2022: power-system device function numbers
Normative device-number publication; exact edition wording and compliance require the licensed standard.
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.
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