Side-by-side reference

Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

First referenceCompare with

S2W

IEC

Two-way light switch plan mark

Two-way switches are installed in pairs at either end of a corridor or staircase so either switch changes the state of the lights. The IEC-style plan form draws the switch circle with strokes in two opposite directions, each with a tick, showing the changeover action.

Drawing use: GA
Application: Installation & communications
Reference family: IEC
Form evidence: Two-way switch. IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.

A distinction that matters

In US terminology this is a three-way switch; the US four-way switch corresponds to the IEC intermediate switch.

Full reference

IEC

Intermediate light switch plan mark

An intermediate switch reverses the connection of the two strapping conductors between a pair of two-way switches, so any number of intermediate switches can be added along a corridor. The plan form uses crossing strokes through the switch circle to suggest the crossover action.

Drawing use: GA
Application: Installation & communications
Reference family: IEC
Form evidence: Intermediate switch. IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.

A distinction that matters

A two-way switch has a changeover contact; an intermediate switch crosses two strappers and is useless without two-way switches either side.

Full reference

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.