Shelly 1 Gen4
Fits behind your switch · Neutral required · Electrician install
In stock · Ships in 1 to 2 business days
Choose options
Customer wants the light on their phone, but the wall switch has to keep working?
The Shelly 1 Gen4 sits behind the existing switch. The switch still turns the light on and off as it always did, and the app, voice and schedules work on top of it. No new switch plate, no extra cabling. Diagram: Shelly.
2-way switched stairs or hallway, and they want app control too?
Keep the existing 2-way wiring. The Shelly 1 Gen4 goes at the light or in the switch enclosure and reads the switch pair on its input, so either switch still works and the app does not fight them. Diagram: Shelly.
3 or more switches on the one light?
Intermediate (cross) switching with the Shelly 1 Gen4 in the circuit: every switch keeps working, and the app shows the true state of the light no matter which switch was used last. Diagram: Shelly.
Customer has momentary push-buttons, not rocker switches?
Set the Shelly 1 Gen4 input to button mode. A short press toggles the load, and the device remembers state, so an apartment-style push-button circuit works with no impulse relay. Diagram: Shelly.
Open the driveway gate from the phone?
The Shelly 1 Gen4 dry contact pulses the gate controller's trigger input, the same as the wall button. Set a 1-second auto-off and the gate opens from the app, Siri or a geofence. Diagram: Shelly.
Buzz the door strike or intercom release from the app?
Wire the Shelly 1 Gen4 dry contact across the existing release button. A short pulse from the app opens the door, and the intercom button keeps working. Diagram: Shelly.
Garden irrigation solenoids on 24 V AC?
The Shelly 1 Gen4 switches the 24 V AC solenoid supply with full SELV separation, so a plug-pack transformer and a dry contact run a zone from the app or a watering schedule. Diagram: Shelly.
Need to control it from a 24 V DC panel: gate, alarm or BMS?
The Shelly 1 Gen4 runs from 24 to 48 V DC and takes its input from a push-button on the same supply, so it drops into a control panel without a 230 V feed. Diagram: Shelly.
Key features
Dry (potential-free) contacts: switches loads isolated from the device's own supply; suits garage doors, gates and mixed-voltage circuits.
Multiprotocol from the factory: Wi-Fi, Bluetooth, Zigbee and Matter built in, no firmware wait.
Works with your ecosystem: Apple Home and Siri via Matter, plus Google Home, Amazon Alexa, SmartThings and Home Assistant.
Flexible power input: runs on 110 to 240 V AC, or low-voltage 12 V / 24 to 48 V DC.
Fits behind the plate: existing switches keep working.
No hub required: full local control, scripting and scheduling via the built-in web interface.
Zigbee and Wi-Fi range extension: strengthens the mesh for other nearby devices.
Works with
Apple Home
via Matter
Google Home
Amazon Alexa
Samsung SmartThings
Home Assistant
Matter
built-in
Shelly Smart Control app
KNX
Zigbee
About this product
The Shelly 1 Gen4 is a single-channel relay built around dry (potential-free) contacts, meaning the switched output is electrically isolated from the device's own power supply, useful for garage doors, gates, or circuits running at a different voltage to the Shelly's supply. It supports low-voltage (12 V and 24-48 V DC) as well as standard 110-240 V AC power, giving it more installation flexibility than the mains-only relays in the range.
Gen4 hardware brings Wi-Fi, Bluetooth, Zigbee and Matter support built in from the factory. It works with Apple HomeKit: control through the Apple Home app or Siri via Matter.
Rated to 16 A on AC or 10 A on 30 V DC, it suits heavier lighting circuits, towel rails, or pump and irrigation control, and runs entirely locally with no hub required: scripting, scheduling, webhooks, MQTT and KNXnet/IP are all supported on-device.
Model: S4SW-001X16EU
Dry-contact relay suited to garage doors, gates and mixed-voltage control as well as standard lighting: licensed electrician required; no neutral-free option on the AC power path.
Tech specs
Physical
| Model | S4SW-001X16EU |
| Dimensions | 37 x 42 x 16 mm |
| Weight | 26 g |
Electrical
| Max load | 16 A/240 V AC or 10 A/30 V DC |
| Power monitoring | No |
| Operating temperature | −20 to 40 °C |
Connectivity
| Wi-Fi | 802.11 b/g/n/ax |
| Bluetooth | 5.0 (LE) |
| Zigbee | 3.0 |
| Matter | Built-in |
Compatibility
| Compatibility notes | Works with Apple Home. |
In the box
| What's in the box | 1 × Shelly 1 Gen4, quick start guide |
Warranty
| Manufacturer warranty | 3 Years |
| Free Ohmly extension | +1 Year Free Ohmly Warranty |
