3-Way Switch Wiring With Power at the First Switch

The most common 3-way layout. Power enters the first switch box, 14/3 cable carries two travelers and a neutral to the second switch, and 14/2 continues to the light.

Safety first. Turn off the breaker and confirm the power is off with a non-contact voltage tester before touching any wire. Follow your local electrical code; some areas require a licensed electrician or a permit. If you find aluminum wiring, cloth-covered wiring, scorched insulation or more than one circuit in a box, stop and call an electrician.

Switch box 1

Grounds: join the bare copper wire in the 14/2 cable bringing power in, the bare copper wire in the 14/3 cable to switch box 2 and a short bare copper pigtail to the 3-way switch 1’s green ground screw under one wire nut.
Neutral splice: join the white wire in the 14/2 cable bringing power in and the white wire in the 14/3 cable to switch box 2 under one wire nut.
3-way switch 1, COMMON screw (the dark/black one) → the black wire in the 14/2 cable bringing power in.
3-way switch 1, traveler screw (brass) → the black wire in the 14/3 cable to switch box 2.
3-way switch 1, other traveler screw (brass) → the red wire in the 14/3 cable to switch box 2.

Switch box 2

Grounds: join the bare copper wire in the 14/3 cable to switch box 1, the bare copper wire in the 14/2 cable to light box and a short bare copper pigtail to the 3-way switch 2’s green ground screw under one wire nut.
Neutral splice: join the white wire in the 14/3 cable to switch box 1 and the white wire in the 14/2 cable to light box under one wire nut.
3-way switch 2, COMMON screw (the dark/black one) → the black wire in the 14/2 cable to light box.
3-way switch 2, traveler screw (brass) → the black wire in the 14/3 cable to switch box 1.
3-way switch 2, other traveler screw (brass) → the red wire in the 14/3 cable to switch box 1.

Light box

Light fixture, black lead → the black wire in the 14/2 cable to switch box 2.
Light fixture, white lead → the white wire in the 14/2 cable to switch box 2.
Light fixture, ground lead or screw → the bare copper wire in the 14/2 cable to switch box 2.

What you need

3-way light switchBuy them in pairs; both ends of the circuit need one.

Check price

14/3 NM-B cableTravelers + neutral + ground between the two switches.

Check price

Non-contact voltage testerConfirms the power is really off before you touch a wire.

Check price

Lever wire connectorsFaster and more forgiving than twist-on wire nuts for pigtails and splices.

Check price

As an Amazon Associate we earn from qualifying purchases, at no extra cost to you.

3-Way Switch Wiring With Power at the First Switch

Which setup do you have?

Flip the switches

Wire it box by box

Switch box 1

Switch box 2

Light box

Other 3-way switch setups

What you need

More wiring tools