WiFi Relay - Shelly Plus i4

The Shelly Plus i4 does not switch anything. It has no output at all, and everything below follows from that.

• Read this first: the Shelly Plus i4 switches nothing
• What it does instead: turns switches into scenes
• Why a physical switch still matters
• What it needs to be wired
• Setup and independence

Read this first: the Shelly Plus i4 switches nothing

It has no output. There is no relay in it and no load terminal. Sitting in a category called relays, that needs saying before anything else.

It is four inputs and nothing more. If you want to switch a light, a pump or a gate, this is the wrong module and you want a Shelly Plus 1 or a Plus 2PM.

What it does instead: turns switches into scenes

Wire up to four switches or buttons to it, and each one can run a scene, a routine or a group of devices anywhere in the house.

One press by the front door turns off every light, closes the curtains and arms the camera. A four gang plate by the bed becomes four scenes instead of four lights. The switch on the wall stops controlling the circuit behind it and starts controlling the house.

Why a physical switch still matters

It is the fastest interface in the house, and it is the only one that works for a visitor, a child, or anybody who does not have the app on their phone.

A smart home that only responds to one person's phone becomes that person's job. This is the module that fixes that, and it is why the i4 is often the second Shelly somebody buys rather than the first.

What it needs to be wired

It goes in the back box at 37 x 42 x 16mm and needs a neutral and a live. An electrician fits it.

It draws under 1W and weighs 18g. Note that it is mains only: there is a separate i4DC model for low voltage, and we do not stock it. If your switches are on a DC circuit, tell us before ordering.

Setup and independence

Bluetooth alongside Wi-Fi, so pairing is done from the phone without joining a temporary network. No hub and no account.

It keeps a local web interface, so the scenes it triggers keep working on your own network with the internet down, provided the devices they control are also local. That is the argument for building a house on Shelly rather than on a cloud platform. Shelly list the whole Plus family at shelly.com.