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

IEEE / ANSI

ANSI four-way switch plan symbol

The S4 symbol marks a four-way switch, which crosses the travellers between two three-way switches. Any number of S4 switches can be added along the travellers, so long corridors and rooms with several entries show S3 at the ends and S4 between.

Drawing use: GA
Application: Installation & communications
Reference family: IEEE / ANSI
Form evidence: Four-way switch, S4. US architectural electrical plan practice in the ANSI Y32.9 lineage, read alongside IEEE 315 context; independently drawn, not a certified IEEE or ANSI graphic.

A distinction that matters

S3 changes over; S4 crosses two travellers and only works between S3 switches.

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.