Two light points you want to automate, still switching from the wall switch they have always had. Dependable, without relying on the wifi having a good day. That is the gap the Shelly Pro 2 fills.
Two genuinely separate channels
The Pro 2 is not one relay split half-heartedly in two: these are two completely independent channels, each with its own 16 A output and its own switch input. The living room and the hallway do not depend on each other, and each answers to its own switch.
Against fitting two small modules in two separate boxes, everything here sits at one point in the board, taking two DIN modules, and is wired once.
The detail to understand: dry contacts
The Pro 2’s outputs are potential-free. The relay supplies no voltage of its own: it closes or opens a contact, and you are the one who brings the live to it.
For two 230 V lights that means a simple bridge: live to both channel inputs, and from each output a cable to its lamp. Neutral goes straight to the fittings. It is an advantage — it even lets you switch circuits on different phases — but worth knowing before you wire, because it does not behave like a module that already has voltage at its output.
A dry-contact output does not mean the device needs no supply. The Pro 2 runs on 110–240 V and needs live and neutral at its supply terminals, quite apart from the live its contacts switch.
For the exact terminals, follow the diagram printed on the device itself and Shelly’s own documentation. The concept is here; the label on each terminal is the manufacturer’s call.
Keeping the switch working without wifi
This is the point most people miss and the one that generates the most support calls. Each channel has its own physical switch input, SW1 and SW2.
- Attached mode: the wall switch acts directly on the relay, locally, without going near the cloud or the router. Lose the internet or the wifi and the lights still switch from the wall exactly as they always did.
- Detached mode: decouples the switch from the relay, and you decide what it does — fire a scene, switch both lights together.
For “each switch runs its own light”, attached is what you want. The automation adds to what you had; it does not replace it.
Ethernet or wifi
Here is the main reason to choose a Pro 2 over a cheaper module.
- Ethernet. It has a wired network socket. If there is an outlet near the board, you get a connection that suffers no interference and no 2.4 GHz congestion. It is what installers want where reliability is not negotiable.
- Wifi. If running cable to the board is not practical, it works over 2.4 GHz like any other Shelly.
- Both at once. It can use the two simultaneously, wired as primary and wifi as backup. If the cable fails one day, it stays connected.
A warning from the documentation itself: the network cable is connected or disconnected only with the device de-energised. Do not plug it in live.
Before you buy it
- It goes in the board, not behind the switch. This is a DIN-rail device. If the plan was to hide it in the back box, you need a different one.
- With only one light, a channel goes to waste. The Shelly Pro 1 does the same with one output, also with Ethernet and DIN rail, and costs less.
- It does not measure consumption. The Pro 2 switches, but has no metering. If you need to know what each light costs, that is a different model.
- You need a neutral at the board. Normal there, but not always in a back box.
Two questions we get
Can I control each light separately from my phone?
Yes. They appear in the app as two independent outputs, each switching and scheduling on its own. You can also group them in a scene to switch both with one tap, without losing the individual control.
Do the lights still work if the internet goes down?
Yes, as long as you leave the inputs in attached mode. The wall switch acts locally on the relay, and that never goes near a server.