Smart Switch Wiring

Neutral wire Not required

There are no standard wiring diagrams for smart switches. The wiring for most brands of smart switches are similar to conventional single pole and 3-way switch wiring. However, all smart switches have their own unique wiring diagrams, even switches of the same brands. These diagrams can be found in the installation instructions included with each switch. It is a good idea to save these instructions for reference, or in case you want to move them.

Replacing a conventional single pole switch with a smart switch can be an easy task, or a little more complex task for a 3-way smart switch.

Do Smart Switches Need a Neutral Wire?

When purchasing a smart switch, first check to see if neutral wires are present in your switch boxes. Some smart switches need a neutral connection and some don’t. It can be very difficult to add a neutral wire to an existing switch box. Do not consider using a ground wire as a neutral for a switch that needs one.

Smart Switch Wiring Diagrams

3-Way Smart Switch Wiring Diagrams

The installation instructions and diagrams for some smart switches are fairly simple for both single pole and 3-way wiring. The Lutron brand of switches fall into this category. They even have a wireless line-side 3-way switch that does not connect to any wires, just mounts to the line side 3-way switch box.

Below are sample diagrams from the installation instructions of Lutron and Leviton smart switches.

Neutral wire required

Lutron Caseta Wireless Dimmer

Lutron Caseta 3-Way Dimmer

Neutral wire required, (wireless line-side switch not shown)

Leviton WiFi Single Pole

Leviton WiFi 3-Way

Neutral Wire Required

Smart Switches

The Smart Home

Replace a 3-Way with a 3-Way Smart Switch on a 3-Way Variation

Replace a 3-way switch with a 3-way smart switch the same way you would replace a 3-way on conventional wiring.

Match each terminal, common to common, and travelers to travelers. Use the included instructions as a guide. Smart switches usually need a neutral wire.

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