Installing Your TP-Link Kasa Smart 3-Way Dimmer Kit (HS210)

What's in the Box

The TP-Link Kasa Smart 3-Way Dimmer Kit HS210 includes two switch units — one smart switch and one companion switch — along with two wall plates, wire nuts, and an installation guide. The HS210 kit is designed for 3-way wiring configurations where two switches control the same light fixture, such as switches at both ends of a hallway or at the top and bottom of a staircase. A neutral wire is required in both switch boxes.

Prerequisites

Before starting, verify the following:

• You have a 3-way switch configuration (two switches controlling one light)
• Neutral wires are present in both switch boxes
• A 2.4 GHz WiFi network is available (the HS210 does not support 5 GHz)
• The Kasa Smart app is installed on your phone
• A Phillips-head screwdriver and a non-contact voltage tester
• Understanding of 3-way wiring, or a licensed electrician available to assist

Step-by-Step Installation

1. Turn off the circuit breaker controlling both switch locations. Verify power is off at both switch boxes using a non-contact voltage tester.
2. Identify which switch box has the line (power from the breaker) and which has the load (wire going to the light fixture). The line box gets the main smart switch, and the load box gets the companion switch. You can determine this by testing which box has a hot wire with the breaker on and the light switched off at the other location.
3. At the line box, disconnect the old switch and connect the main HS210 switch: black wire to line, red wire to the traveler wire going to the companion switch, white wire to neutral, and green wire to ground.
4. At the load box, disconnect the old switch and install the companion switch: black wire to load, red wire to the traveler wire from the main switch, white wire to neutral, and green wire to ground.
5. Carefully tuck wires into both boxes, mount both switches with screws, and attach the included faceplates.
6. Restore power at the breaker. Both switches should light up with their LED indicators.

App Pairing and Configuration

Open the Kasa Smart app and tap "+" to add a device. Select "Smart Switches" and choose the HS210 3-way kit. The app will connect to the main smart switch over WiFi. The companion switch does not need separate app setup — it communicates with the main switch through the traveler wire. Once paired, you can control the light from either physical switch, the Kasa app, or through voice assistants. Set up schedules, countdown timers, and "Away Mode" from the app for automated control of the fixture.

Smart Home Integration Tips

The HS210 works with Amazon Alexa and Google Assistant. After linking your Kasa account, you can use commands like "Alexa, turn off the hallway light" or "Hey Google, turn on the stairway." Both physical switches continue to work normally, so family members can use either switch without needing the app. Combine the HS210 with other Kasa devices in scenes — for example, create a "Goodnight" scene that turns off the hallway lights, locks the smart plug on the coffee maker, and dims the bedroom bulbs all at once.

Quick Troubleshooting

If one switch works but the other does not, verify the traveler wire is properly connected at both locations. A loose traveler wire is the most common issue with 3-way installations. If neither switch powers on, check that the neutral wire connections are secure in both boxes. If the switches are physically working but not connecting to WiFi, hold the reset button on the main switch for 5 seconds to restore factory settings. The companion switch does not have WiFi — it only needs a physical connection to the main switch through the traveler wire, so focus WiFi troubleshooting on the main switch only.