A relay hides inside the wall box behind your existing switch, so the room looks and works exactly as before while the circuit becomes controllable. This is what makes retrofitting acceptable in a household that did not ask for a smart home: nothing visible changes, and the switch still works for everyone.
How it fits
The module is small enough to sit behind a standard switch in the back box. Live and neutral feed the relay, the relay feeds the lamp, and the existing switch becomes an input telling the relay to toggle rather than breaking the circuit itself.
The consequence matters: the relay always has power, so it is always reachable, whatever position the wall switch is in. This is the fundamental advantage over smart bulbs, which lose power the moment someone flips the switch.
Choosing a model
- 1 / 1 Mini — switching only, one circuit. Cheapest way to make a light smart.
- 1PM / 1PM Mini — adds power measurement, so you see what that circuit consumes.
- 2PM — two independent circuits with measurement each. Ideal where one switch box serves two circuits, such as a room light and an outside light.
- Dimmer — for dimmable lighting; note the no-neutral variant if your box lacks one.
- Shutter / Cover — drives blinds and roller shutters, including the interlock that stops both directions energising together.
- RGBW — controls LED strip, colour and white channels.
The Mini versions exist for one reason: back box depth. Older Egyptian installations frequently have shallow boxes, and a full-size module will not physically fit. Measure before ordering.
What you need at the box
Most relays require a neutral at the switch. If yours has only live and switched-live, install the relay at the ceiling rose instead — the neutral is almost always present at the fitting.
What it enables
- App and voice control, with the physical switch still working normally.
- Schedules — outdoor lighting at dusk, off at a set hour.
- Scenes — several circuits responding to one action.
- Consumption data per circuit on PM models.
- Local operation, so automations survive an internet outage.
Installation reality
This is work inside a live wall box and belongs to a qualified electrician. It is quick — typically fifteen minutes per switch once the circuit is isolated — but it is not a DIY job, and an incorrectly wired relay can present a shock risk at a switch that looks entirely ordinary.
Do one circuit first and live with it for a week before doing the rest of the house. You will discover which rooms genuinely benefit and which never get used from an app.
See Smart Relays and Pro Series Devices.
Frequently asked questions
Will my existing switch still work?
Yes. That is the main advantage — anyone can use the room normally without an app.
Does it fit any switch box?
Standard boxes yes; shallow boxes need a Mini. Measure the depth first.
What happens if the Wi-Fi fails?
The wall switch continues to work, and locally stored schedules keep running.