Interactive diagram

Smart Dimmer Switch Wiring With a Neutral Wire

Smart dimmers need constant power for their radio, so they have a neutral lead. LINE takes the incoming hot, LOAD feeds the light, and a white pigtail joins the neutral bundle in the back of the box.

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

Tool

Interactive dimmer 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

Lead colors vary by brand. Check the label: LINE goes to the incoming hot, LOAD to the light.

The neutral pigtail joins the existing white bundle. Don’t use a white wire that was connected to the old 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.

Switch box

Grounds: join the bare copper wire in the 14/2 cable bringing power in, the bare copper wire in the 14/2 cable to light box and the smart dimmer’s green ground lead under one wire nut.
Neutral splice: join the white wire in the 14/2 cable bringing power in, the white wire in the 14/2 cable to light box and the smart dimmer’s NEUTRAL lead (white) under one wire nut.
Smart dimmer, LINE lead (usually black) → the black wire in the 14/2 cable bringing power in.
Smart dimmer, LOAD lead (usually red) → the black wire in the 14/2 cable to light box.

Light box

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

Other dimmer switch setups

What you need

LED dimmer switchSingle-pole and 3-way capable, rated for LED and incandescent bulbs.
Check price
Smart dimmer (neutral required)Wi-Fi dimmer for boxes with a neutral wire.
Check price
No-neutral smart dimmerFor switch boxes without a neutral.
Check price
Non-contact voltage testerConfirms the power is really off before you touch a wire.
Check price

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Smart Dimmer Switch Wiring With a Neutral Wire

Which setup do you have?

Flip the switch

Wire it box by box

Switch box

Light box

Other dimmer switch setups

What you need

More wiring tools