Quick answer
A four-way switch is a light switch with four traveler terminals that is installed between two three-way switches, letting one light be turned on and off from three or more locations.
It never works alone: each flip either passes the two traveler wires straight through or crosses them over, which reverses the state of the light, and you add one four-way for each extra location.
Quick facts
The key facts about Four-Way Switch, with sources:
- Used with
- Two three-way switches, one at each end of the chain
- Terminals
- Four traveler terminals, plus ground
- Internal design
- Double-pole, double-throw, wired to pass travelers straight or crossed
- Locations
- Two three-ways + N four-ways = N + 2 control points
- Smart option
- Smart switch plus companion units; Leviton D215S (discontinued; replacement D315S-1BW) pairs with wired or wire-free companions 6
- Dimming
- Lutron: a Lumea dimmer works in a 4-way setup at a 3-way end, with standard switches elsewhere 5
Key takeaways
- A four-way switch adds a third (or fourth, fifth…) control point between two three-way switches.
- It has four terminals, all for travelers, and no ON/OFF markings.
- Each flip swaps how the two travelers connect, which flips the light.
- Every chain starts and ends with a three-way; four-ways only go in the middle.
- Dimming from more than one location takes a master-and-companion dimmer system rather than a standard four-way.
What a four-way switch is
A four-way switch is the middle switch in a run of three or more switches that control one light. Long hallways with several doors, open-plan rooms, large garages and stairs with a landing entrance are typical places.
The name counts terminals, not locations: a four-way has four terminals for travelers, plus a ground screw. A three-way switch has three.
You cannot use a four-way on its own or at the end of a chain, because the ends are always three-ways.
How a four-way switch flips the light
In a pair of three-ways, two traveler wires run between the switches, and the light is on when both three-ways connect their common to the same traveler.
A four-way sits on those two travelers, and in one position it passes them straight through: A stays A and B stays B. In the other position, it crosses them: A becomes B and B becomes A. Crossing the travelers reverses which one the far three-way receives, so the light changes state.
Because each four-way only swaps or passes, you can chain as many as you need, and each one adds a control point.
- Hot from the panelTo the common of three-way #1
- Three-way #1Sends power on traveler A or B
- Four-wayPasses A and B straight, or crosses them
- Three-way #2Its common picks A or B
- LightChanges state when any switch is flipped
What the four-way does in each position
| Four-way position | Traveler A leaves as | Traveler B leaves as |
|---|---|---|
| Straight | A | B |
| Crossed | B | A |
Types of four-way and multi-location controls
| Type | How it works | Notes |
|---|---|---|
| Mechanical four-way | Swaps or passes the travelers | The standard middle switch |
| Four-way in a dimmer chain | One three-way end holds the dimmer | Lutron Lumea: dimmer at a 3-way end, standard switches elsewhere 5 |
| Master + companion dimmers | Companion dimmers take the other locations | Lutron: needed to dim from more than one place 5 |
| Smart switch + companions | One smart unit; companions at other spots | Leviton D215S pairs with wired or wire-free companions; Leviton now lists it as discontinued, with the D315S-1BW as replacement 6 |
Example: counting switches for a hallway with four doors
A simple count shows how many of each switch the job needs.
| Control points wanted | Three-way switches | Four-way switches |
|---|---|---|
| 2 | 2 | 0 |
| 3 | 2 | 1 |
| 4 | 2 | 2 |
| 5 | 2 | 3 |
Four-ways = Locations − 2 · Three-ways = 2
Locations- Number of places you want to control the light from
Three-ways- Always two, one at each end
Four-ways- One per middle location
The rule is always two three-ways, plus one four-way for each location beyond two. A hallway with four doors needs two three-ways and two four-ways.
A second example: a garage with three doors
Picture an attached garage with a door from the kitchen, a side door to the yard and a wide overhead door. The owner wants the ceiling lights from all three, which makes three locations, so the job needs two three-way switches and one four-way.
The electrician puts a three-way by the kitchen door, the four-way by the side door and the other three-way by the overhead door. Two traveler wires link all three boxes, so flipping any one of them changes the lights.
If the side door has no box and the wall is finished, a smart main switch with a wire-free companion at the side door can avoid opening the wall. That trade-off, wire versus wireless, is the real decision on most four-way jobs.
Where four-way switches show up
Four-ways are less common than three-ways; you find them in long hallways, great rooms with three entrances, garages with a house door, a side door and an overhead door, and stairs where a landing has its own entrance.
The 2023 NEC 210.70 asks for a wall-mounted lighting control at each floor level and at each landing level for interior stairs with six or more risers 2. A stair with a landing level between two floors may need three control points, which means a four-way in the middle.
Plan locations before work starts; the lighting circuit planner helps you list them.
Benefits and drawbacks
What it does well
- Light from every doorway in large or open spaces.
- Unlimited control points by chaining more four-ways.
- Mechanical parts are simple and long-lived.
- Helps meet stair lighting rules where landings have entrances 2.
Where it falls short
- Needs travelers run through every switch box in the chain.
- Hard to troubleshoot: one bad switch or loose wire breaks the chain.
- Dimming from more than one spot needs a master and companion system 5.
- More boxes and wire than a smart system with wire-free companions.
Limits and common mistakes
The most common mistake is putting a three-way in the middle of a chain or a four-way at an end. Either mistake breaks the logic, and the light works only in some switch positions.
Mixing smart brands is another mistake: smart systems often expect their own companion devices, and a standard four-way in a smart chain may not work, so check the maker’s wiring guide.
Troubleshooting time is a third limit, because two switches have only four combinations to test, a chain with one four-way has eight, and each added four-way doubles the count, which is why faults in long chains take longer to trace, and why careful labeling of travelers at install time pays off later.
Three-way vs four-way
A three-way has a common and two travelers and goes at the ends. A four-way has four traveler terminals and goes only in the middle.
What drives the cost
We do not print prices, but the main drivers are the number of locations, whether cable must be run between boxes through finished walls, wall repair, and whether you choose standard, dimming or smart devices. Smart systems with wire-free companions can avoid new cable. Our project cost tool lists the drivers.
Replacing a worn four-way in an existing chain is usually a small job, because the travelers are already in place. Adding a new location costs more, because the electrician must reach both neighboring boxes with new cable. Ask the electrician to quote both a wired and a smart option so you can compare.
Warranty depends on the device; smart switches often carry one- or two-year limited warranties, such as two years on the Leviton D215S 6.
How an electrician sets up multi-location control
Multi-location switch wiring is licensed work, so this page lists what the electrician does rather than giving wiring steps.
- List every control location you want.
- Map existing boxes and any cable between them.
- Decide on standard switches, a dimmer at one end, or a smart system with companions.
- With the circuit off and verified dead, install three-ways at the ends and four-ways in the middle.
- Test every combination so each switch flips the light.
Owner checks
- Switches should be cool to the touch, per CPSC 7.
- If one switch stops working, note which one and which positions fail.
- A switch that feels mushy, crackles or sparks needs replacing by an electrician.
- Keep cover plates on and intact.
- Keep a simple sketch of which switches belong to the chain, taped inside a closet or kept with house papers.
- When you repaint, keep paint off the toggles and out of the gaps around them.
Warning signs
Intermittent operation, a warm plate, buzzing or flicker when you touch a switch can point to a loose terminal. Older devices with push-in terminals are a common suspect; NEC 2023 404.14(D) limits push-in terminals on snap switches to 15-amp circuits and 14 AWG solid copper 4.
Every box can be live
In a multi-location chain, travelers carry power through several boxes. A switch in the off position does not make its box safe. Leave troubleshooting to an electrician.
Code rules
NFPA 70, the National Electrical Code, governs the installation as adopted locally.
The 2023 NEC 210.70 sets where lighting controls are required, including the stair rule for six or more risers, and allows remote, central or automatic control in hallways, stairways and at outdoor entrances 2.
The same section limits controls that rely only on a battery 3.
NEC 404.2(C) requires a neutral at switch locations controlling lighting, with exceptions, a rule the 2023 edition keeps, which matters if you plan smart controls 1.
Four-way compared with related switches
Myths
- Myth Four-way means four locations.
- Reality It means four terminals, and two three-ways plus one four-way control three locations.
- Myth A four-way can go at the end.
- Reality The ends must be three-ways.
- Myth Any dimmer can replace a four-way.
- Reality Lutron puts its Lumea dimmer at one location only, with standard switches such as its CA-4PS four-way elsewhere 5.
- Myth A broken four-way kills only its own location.
- Reality One faulty switch can break control from every location.
Your code edition
Standard four-ways or a smart system?
Both give control from many places, so the choice comes down to wiring and features.
- If Travelers already run between all boxes
- Then Standard three-ways and four-ways
- If New location where running cable is hard
- Then Smart switch with a wire-free companion
- If Want dimming from every spot
- Then Master dimmer with companions
- If Chain works only in some positions
- Then Call an electrician to trace the fault
Count first
Tell the electrician the number of locations. Two three-ways plus one four-way per extra location gives the parts list.
Questions about Four-Way Switch
What is a four-way switch used for?
It lets you control one light from three or more places by sitting between two three-way switches, and each four-way you add creates one more control point.
How many four-way switches do I need?
Subtract two from the number of locations: three locations need one four-way, four locations need two. You always need exactly two three-way switches, one at each end.
How is a four-way different from a three-way switch?
A three-way has a common terminal and two travelers and goes at the ends of a chain. A four-way has four traveler terminals and only goes in the middle. It passes the travelers straight through or crosses them.
Can a four-way switch work by itself?
No. A four-way only swaps two traveler wires, so it needs a three-way at each end to form a working circuit.
How do I tell if a switch is a four-way?
It has no ON or OFF marks and four terminal screws, not counting the green ground. It usually sits in the middle of three or more switches that control the same light, and an electrician can confirm it with the power off.
Can I put a dimmer in a four-way circuit?
Yes, at one of the three-way ends with the right product. Lutron says a Lumea dimmer can be used in a four-way setup with standard switches at the other spots. To dim from every location, use a master dimmer with companions.
Why does my four-way circuit only work sometimes?
A loose wire, a failed switch or a three-way and four-way placed in the wrong spots can cause it. Note which switch and positions fail and call an electrician, since several boxes can be live.
Are smart switches easier than four-ways?
Often, especially where new cable would be hard to run. Many smart systems use one main switch and companion units, some wire-free, and they usually need a neutral at the main switch.
Do stairs need four-way switches?
Only when three control points are needed, because the 2023 NEC asks for a control at each floor level and landing level on interior stairs with six or more risers. A stair with a landing level between floors can need a four-way.
Do four-way switches wear out?
Like any switch, the contacts and terminals can wear or loosen. A switch that feels loose, crackles or gets warm should be replaced by an electrician.
Sources
- Electrical Association (Minneapolis), 2023 NEC Update Part 3 training slides, 404.2(C) Switches Controlling Lighting Loads, retrieved .
- Leviton Captain Code (NEC 2023), Lighting Outlet Locations and Limitations (210.70), retrieved .
- Leviton Captain Code (NEC 2023), Limitations on Battery Powered Light Switches and Laundry Area Switch (210.70), retrieved .
- Leviton Captain Code (NEC 2023), Switches and Receptacles with Push-In Terminals & Wire Types (404.14(D)), retrieved .
- Lutron Support, Lumea dimmer multi-location control FAQ, retrieved .
- Leviton, D215S-1BW Decora Smart Wi-Fi Switch specifications (marked discontinued; suggested replacement D315S-1BW), retrieved .
- US CPSC, Home Electrical Safety Checklist (Pub 513), retrieved .
- Texas Department of Licensing and Regulation, 2023 National Electrical Code is almost here, retrieved .
- Washington State Register WSR 25-23-069 (L&I adopts the 2026 NEC), retrieved .
Expert review
Written by the HyreElectrical Research team. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: Switch logic is standard traveler crossover shown as tables. Code rules follow Leviton’s NEC 2017 and 2023 guides (210.70, 404.2(C), 404.14(D)). Dimmer and smart pairing come from Lutron support and the Leviton D215S data sheet. No DIY wiring; no prices under G-COST.
Suggest a correction. We fix errors and say what changed.