# ANSI four-way switch plan symbol

Canonical URL: https://eloragrid.ai/symbols/ansi-four-way-switch
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: S4
Drawing use: GA
Reference families: IEEE / ANSI

## Symbol convention

Convention: IEEE / ANSI
Form: 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.

US plan symbol S4 for a four-way switch placed between two three-way switches to add control points.

## In plain English

### What does ANSI four-way switch plan mean?

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.

### A simple example

Reading the plan, the installer checks that S4 never appears without a pair of S3 switches on the same group. The IEC equivalent is the intermediate switch.

### What the drawings help you do

The symbol gives no information about the device rating or style. Smart switching systems may replace this wiring scheme with a master and companion device, which should be noted.

### This particular reference

US plan symbol S4 for a four-way switch placed between two three-way switches to add control points. S3 changes over; S4 crosses two travellers and only works between S3 switches.

### Terms

- Normally open / normally closed: The contact state in the normal condition defined for the drawing.
- Rating: A value stating the conditions for which equipment is specified.
- Schematic: A drawing showing function and connections rather than physical appearance.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/)


## What it represents

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.
Reading the plan, the installer checks that S4 never appears without a pair of S3 switches on the same group. The IEC equivalent is the intermediate switch.
The symbol gives no information about the device rating or style. Smart switching systems may replace this wiring scheme with a master and companion device, which should be noted.

## How to read it

- Confirm two S3 switches exist on the same group.
- Watch for smart-switch notes that change the wiring scheme.

## Information to show or reference

- Show S3 at each end.
- Number control points for clarity.
- State any smart-control alternative.

## Important distinction

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

## Facts

- Contact: Crossover of two travellers
- IEC equivalent term: Intermediate switch
- Artwork scope: Original educational illustration; the exact ANSI or IEEE graphic and compliance are not certified

## Public references

- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/) — IEEE Standards Association. Graphic-symbol standards context; not a source of reproduced artwork.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.