Single-Pole, 3-Way and 4-Way Switch Diagrams

Compare single-pole, 3-way, and 4-way switch circuit diagrams, identify commons and travelers, and separate topology from device instructions.

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Single-pole switch

A conventional single-pole switch opens or closes the ungrounded path feeding one load from one location. The neutral return shown here goes directly to the load. “Single-pole” describes the switching function, not a guarantee about the number of terminals on every electronic device.

Single-pole lighting circuit topologyLine passes through a single switch to a lamp. Neutral returns from the lamp without passing through the switch. Equipment grounding paths are omitted for schematic clarity.LineNeutral: direct return to sourceLampSingle-pole switch
Single-pole lighting circuit topology. Contact positions are illustrative. This is a functional schematic; conductor routing, grounding connections, box fill, and device-specific requirements are not shown.

The switch being open does not establish a de-energized work area. Other supplies, incorrect wiring, or a different device arrangement may be present.

Two 3-way switches

A conventional 3-way switch connects its common terminal to one of two traveler terminals. A pair provides two possible paths between locations. The light is on when the selected contacts make a continuous path through the travelers; the physical handle directions are not a reliable on/off legend.

Two 3-way switches controlling one loadThe line conductor connects to the first common; two travelers connect the switching points; the last common feeds the lamp. Neutral returns directly from the lamp. The drawn contact positions are one possible state. Equipment grounding paths are omitted for schematic clarity.LineNeutral: direct return to sourceLampCommonCommonTraveler 1Traveler 23-way3-way
Two 3-way switches controlling one load. Contact positions are illustrative. This is a functional schematic; conductor routing, grounding connections, box fill, and device-specific requirements are not shown.

The first common is on the source side and the last common feeds the switched load in this topology. The common is a terminal function, not a neutral connection. Identify it from the device marking or instructions instead of assuming a screw position.

A 4-way switch between two 3-way switches

The intermediate 4-way switch passes the two traveler paths straight through or crosses them. It has two traveler pairs and sits between the two end switches; it does not replace either end switch’s common terminal.

Two 3-way switches and one intermediate 4-way switchThe line conductor connects to the first common; two travelers connect the switching points; the last common feeds the lamp. Neutral returns directly from the lamp. The drawn contact positions are one possible state. Equipment grounding paths are omitted for schematic clarity.LineNeutral: direct return to sourceLampCommonCommonTraveler 1Traveler 23-way3-way4-way crossover
Two 3-way switches and one intermediate 4-way switch. Contact positions are illustrative. This is a functional schematic; conductor routing, grounding connections, box fill, and device-specific requirements are not shown.

The crossover is drawn in one illustrative position. A drawing of an unswitched straight-through state would show the travelers continuing without crossing. Follow the manufacturer’s pair identification: terminal order and physical placement can differ.

Match the actual device

  • Retrieve the instructions for the precise catalog number, voltage, load type, and multi-location arrangement.
  • Distinguish conventional switches from dimmers, smart switches, and companion/remotes. Some require a neutral or a specific companion and cannot use these topologies directly.
  • Separate a functional schematic from a cable-routing diagram. The location of the feed and the load changes how conductors travel through boxes.
  • Confirm grounding and bonding, conductor identification, box fill, and applicable neutral-at-switch requirements separately.

See the symbol legend for diagram conventions and the wire color reference for the difference between identification and convention. Leviton’s linked support page supplies product instructions and manufacturer diagrams.

Sources

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