Texas Electrician ExamTexas journeyman & master

Checked against primary sources 2026-09-04

4-Way Switch Wiring Explained: Between Two 3-Way Switches

A four way is the switch you add when two locations are not enough. It has no common, it is never the source and never the load, and it does exactly one job: it swaps the travelers passing through it.

Open the lab: drag the wires, flip the switches, watch the light

On this page
  1. Where the four way sits
  2. The two pairs of terminals
  3. Any number of four ways
  4. The common trap
  5. The same neutral and re-identification rules
  6. What the exam asks
  7. Questions people ask
  8. What this page cites

Where the four way sits

A four way never goes on the end of a run. It sits in the middle, in the travelers, between two three ways. The three ways are still the two ends of the circuit, and they still carry the common that takes the supply at one end and the switched leg at the other.

That is the sentence to hold on to, because it answers most of the questions on its own. If a four way is at the end of the run, something is wrong with the drawing rather than with the switch.

Everything 406.30(A) says about a three way applies here too, in the same words: three way and four way switches are wired so all switching is done only in ungrounded circuit conductors, and where the run is in metal raceway or metal-armored cable, the wiring between switches and outlets complies with 300.22(A).

The two pairs of terminals

A four way has four screws in two pairs. One pair takes the two travelers arriving from the first three way. The other pair sends two travelers on toward the second three way, or on to the next four way if there is one.

Flipping it swaps which incoming traveler feeds which outgoing traveler. That is the whole function. It reverses the pair without ever becoming the source and without ever becoming the load.

This is why a four way has no common screw. There is no odd conductor at this position, because nothing starts or ends here. Anything that looks like a common on a four way is a misread of the strap.

Manufacturers do not all arrange the pairs the same way on the yoke, so the pairing is a fact about the device in your hand. The screws that belong together are marked on the strap or in the instructions, and getting the pairing from the geometry of the box rather than from the device is the usual way this goes wrong.

Any number of four ways

One four way gives you three locations. Two give you four. There is no ceiling in the rule: you can put as many four ways in the travelers as the job wants, in series with each other, and the circuit still behaves.

The reason is that each one only reverses the pair. Reverse a pair an even number of times and it comes out as it went in, reverse it an odd number of times and it comes out swapped, and either way the two three ways at the ends still decide what is connected to what.

The travelers stay a pair through the whole chain. Whatever leaves the first three way as a matched pair arrives at the second three way as a matched pair, however many four ways it passed through on the way.

The common trap

The usual failure is wiring the four way across the wrong pairs: one incoming traveler and one outgoing traveler landed on the same pair of screws, instead of both incoming on one pair and both outgoing on the other.

What that produces is a circuit that does nothing from that location, or one that stops the run in some positions and works in others. It reads as a bad switch, and switches get replaced over it.

The other trap is landing the supply or the switched leg on a four way at all. There is no common here, so anything that starts or ends the run belongs on a three way at one of the two ends.

The check is the same as for a three way and it is worth doing every time: walk every combination of every switch. With three locations that is eight positions, and each one of them should change the light from wherever the others happen to be.

The same neutral and re-identification rules

406.30(C) does not treat a four way location differently. Where switches control lighting loads on a grounded general-purpose branch circuit serving a bathroom, a hallway, a stairway, or a habitable room or occupiable space as the building code defines it, the grounded conductor of the controlled lighting circuit is required at the switch location.

The same allowance applies as well, and with three locations it is worth reading twice. Where several switch locations control the same lighting load and the whole floor area of the room is visible from those locations taken together, the grounded conductor is only required at one of them.

The four conditions that remove the requirement are the same four: a raceway into the box large enough for all the conductors including a grounded one, a snap switch with the kind of integral enclosure 300.17(E) covers, lighting controlled from a remote location, and a switch controlling a receptacle load. The retrofit exception is the same too.

Re-identification works the same way. A white in a cable assembly can be a traveler through a four way where it is permanently marked under 200.8(C)(1)(a), because 200.8(C)(1)(b) allows a re-identified conductor as the supply to the switch and never as the return from a switch back to the outlet. And grounding the device is 406.40(B) again, with 406.44 for the box.

What the exam asks

Four way questions are usually about position and about pairing. Where in the circuit the device goes, how many of them are allowed, which screws are a pair, and what happens when the pairs are crossed.

The wrong answers lean on the three way. An option that gives the four way a common screw is testing whether you know it has none. An option that limits you to one four way is testing whether you know the rule sets no number. An option that puts the four way at the end of the run is testing whether you know the three ways own the two ends.

And the neutral questions get reused here, because the shape of the answer changes with three locations rather than two. Read the allowance in 406.30(C) carefully: it is about what is visible from the switch locations taken together, not about how many switches there are.

Questions people ask

Where does a 4-way switch go in the circuit?

In the travelers, between two three way switches. The three ways are always the two ends of the run, one taking the ungrounded supply on its common and the other sending the switched leg on to the light. A four way at the end of a run is a drawing error rather than a wiring option.

How many 4-way switches can you have?

As many as the job needs. Each one adds a control location, so one four way gives three locations and two gives four. Nothing in 406.30 sets a number, because each four way only reverses the traveler pair passing through it and the two three ways still decide the outcome.

Does a 4-way switch have a common screw?

No. A four way has four screws in two pairs, one pair for the travelers arriving and one pair for the travelers leaving, and nothing starts or ends at that position. Only a three way has a common, and it takes the odd conductor: the supply at one end, the switched leg at the other.

What happens if you wire a 4-way across the wrong pairs?

You get a switch that does nothing, or one that kills the run in some positions and not others, and it reads as a faulty device. The fix is to land both incoming travelers on one marked pair and both outgoing travelers on the other, taking the pairing from the strap rather than from where the screws sit on the box.

Does a 4-way switch need a neutral at the box?

406.30(C) applies to the location, not to the type of switch, so the answer is the same as for a three way. Where the load is on a grounded general-purpose branch circuit serving a bathroom, hallway, stairway or habitable room or occupiable space, the grounded conductor is required at the switch location, unless the whole floor area is visible from the locations together, in which case one of them carries it, or one of the four listed conditions applies.

Can a white conductor be a traveler through a 4-way?

Yes, where it is permanently re-identified. 200.8(C)(1)(a) allows a white in a cable assembly to serve as an ungrounded conductor, and it sets the marking: it encircles the insulation in a color other than white, gray or green, at the termination and wherever else the conductor is visible and accessible. A traveler supplies the switch beyond it, so 200.8(C)(1)(b) is satisfied.

Try it hands-on

Put a four way in the middle and walk all eight positions

Level three of the lab is a four way between two three ways. Drag the conductor ends onto the screws, cross the pairs on purpose, and press Check it for the toggle table and the section behind each fault.

Open the switch wiring labStart the free questions

Free, no account, and every fault it names carries the section it comes from.

What this page cites

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