Shelly · Shelly 1PM Series

SNSW-001X16EU

Active
CE UL

Shelly 1PM Gen3 WiFi Relay Behind Switch

Shelly Shelly 1PM Series Introduced circa 2024

Shelly 1PM Gen3 — WiFi relay that installs behind any existing wall switch.

Common Applications

Turns any dumb wall switch into a smart switch. Installs behind the existing switch in the junction box. Local HTTP API + MQTT — no cloud needed. Power monitoring (PM = Power Metering). ESP32-based — flashable to ESPHome or Tasmota. The most flexible smart switch solution: keeps your existing switches, adds smart control.

Openness & Hackability

Fully Open

Custom firmware: Stock (local HTTP/MQTT/CoAP), Tasmota, ESPHome

The gold standard for hackable behind-switch relays. Local API works without internet. OTA flashable to Tasmota/ESPHome. Auto-discovered by Home Assistant. Power consumption monitoring included.

Specifications

Certifications
CE, UL
Smart Home Integrations
Home Assistant, MQTT, Alexa, Google Home, Shelly Cloud (optional)
Mounting Type
Behind wall switch (DIN rail option available)
Protocol
WiFi 2.4GHz + Bluetooth

Installation Quick Reference

Setup: Pair with your hub or phone via WiFi 2.4GHz + Bluetooth. Most smart buttons support single press, double press, and long press for three different actions.

Battery: Uses CR2032 battery. Expected life: 1-2 years. Low battery notification via the app.

Dimensions

Troubleshooting

Not responding to input

Check wiring continuity with a multimeter. Verify the contact block is properly seated. Inspect terminals for loose connections.

Where to Buy

Price range

$95.85 — $130.84

across 2 distributors

Quick Specs

Certifications
CE, UL
Smart Home Integrations
Home Assistant, MQTT, Alexa, Google Home, Shelly Cloud (optional)
Mounting Type
Behind wall switch (DIN rail option available)
Protocol
WiFi 2.4GHz + Bluetooth

What People Are Saying

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“Turns any dumb wall switch into a smart switch. Installs behind the existing switch in the junction box. Local HTTP API + MQTT — no cloud needed. Power monitoring (PM = Power Metering). ESP32-based — ”

Reddit r/PLC 21 upvotes View thread →