Interactive diagram

Light Switch Wiring With Power at the Light

Power reaches the light box first, and a 14/3 cable drops down to the switch. Black carries constant hot to the switch, red brings the switched hot back to the fixture, and the white neutral is capped in the switch box for later.

Buying a smart switch? Check if your box has a neutral wire first.

Tool

Interactive light switch wiring diagramThree steps: pick your setup, flip the switches, wire it

Step 1 of 3

Which setup do you have?

Look in the box with the breaker off: what matters is where the power cable comes in. Pick the one that matches, or keep the one already selected.

Step 2 of 3

Flip the switch

Tap a switch, button or GFCI on the diagram. Glowing wires are carrying power right now. On a small screen, scroll the diagram sideways.

Show power flow

Black: hot
White: neutral
Red: hot / traveler
White + black tape: hot
Bare copper: ground
Wire nut
Glow: carrying power now

The red wire is the switched hot back to the light. The white wire stays capped in the switch box as a neutral for a future smart switch.

Step 3 of 3

Wire it box by box

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.

Light box

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 and the light fixture’s ground lead or screw under one wire nut.
Hot splice: join the black wire in the 14/2 cable bringing power in and the black wire in the 14/3 cable to switch box under one wire nut.
Neutral splice: join the white wire in the 14/2 cable bringing power in, the white wire in the 14/3 cable to switch box and the light fixture’s white lead under one wire nut.
Light fixture, black lead → the red wire in the 14/3 cable to switch box.

Switch box

Grounds: join the bare copper wire in the 14/3 cable to light box and a short bare copper pigtail to the switch’s green ground screw under one wire nut.
Cap the white wire in the 14/3 cable to light box with a wire nut. This is the neutral. Leave it capped in the box: a smart switch will need it later.
Switch, brass screw (either one) → the black wire in the 14/3 cable to light box.
Switch, other brass screw → the red wire in the 14/3 cable to light box.

Other light switch setups

What you need

Single-pole light switch15 A decorator or toggle switch with screw terminals.
Check price
Non-contact voltage testerConfirms the power is really off before you touch a wire.
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Lever wire connectorsFaster and more forgiving than twist-on wire nuts for pigtails and splices.
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Wire stripperStrips 14 and 12 AWG cleanly and has a gauge for exact strip length.
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Light Switch Wiring With Power at the Light

Which setup do you have?

Flip the switch

Wire it box by box

Light box

Switch box

Other light switch setups

What you need

More wiring tools