SPDT switch symbol
Also called Single pole double throw, Changeover switch, Two-way switch, 3-way switch
A single pole, double throw switch connects one common terminal to one of two others. In building wiring a pair of them switches a light from two places: a two-way switch in the UK, a 3-way switch in the US.
What the SPDT switch symbol means
A single pole, double throw switch connects one common terminal to one of two others. In building wiring a pair of them switches a light from two places: a two-way switch in the UK, a 3-way switch in the US.
ANSI and IEC symbols
Where you see it
Selector switches, changeover between two circuits, and switching lights from two places.
What is written next to it
On a schematic, the SPDT switch usually carries its designator, such as S2.
Related symbols
Frequently asked questions
What does the SPDT switch symbol look like?
On ANSI drawings: A blade from the common terminal, resting on one of two contacts. In IEC 60617: The same change-over blade.
Is the SPDT switch symbol the same in IEC and ANSI?
Yes, it is drawn the same way in most legends.
Where is a SPDT switch used?
Selector switches, changeover between two circuits, and switching lights from two places.
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