Make Existing Switches Smart with a Wi-Fi Relay (UAE Guide)

If you like your current UK-style switch plates, or you rent and cannot change them, a Wi-Fi relay is the least visible way to add smart control. The relay sits out of sight, switches the circuit on and off, and keeps an input connected to your existing switch so that it still works as a normal switch.

In practice, the main question is not whether it works but where the relay physically goes and what wiring is available there. This guide covers both, and also looks at fans, garage doors, water heaters and energy monitoring.

What a Wi-Fi relay does

A relay is an electrically controlled switch. A Wi-Fi relay adds a small radio and a controller, so the circuit can be switched from a phone app, a voice assistant, a schedule or an automation. Most models also have a switch input. Your existing wall switch is wired to that input, so pressing it tells the relay to change state instead of breaking the circuit directly.

The relays in our Wi-Fi Relays range include:

• Luxion Mini-Smart Wi-Fi Relay (TDQ-DS1G-WF): 1 input and 1 output, with app control, schedules, automations and Alexa or Google Home voice control. From AED 47.
• Sonoff Mini-Dim: a compact dimmer relay with energy monitoring that fits behind an existing switch. It supports Matter for Apple Home, Google Home and Alexa. From AED 120.
• Sonoff Mini-D: a Matter-certified dry-contact relay that works with Alexa, Google Home, Apple Home and Home Assistant. From AED 65.
• Luxion 4-Channel Wi-Fi Smart Relay (LX-R4CH): four outputs with app and voice control and on/off timers. From AED 126.

Alexa officially launched in the UAE in December 2021 and supports English and Khaleeji Arabic. Before you buy, check the product page for the voice assistant you use.

Behind the switch or at the light

There are two usual places to fit a relay.

Behind the switch

The relay goes into the back box behind your existing switch plate. Your electrician connects the incoming supply, the load and the switch input. This works well when the back box is deep enough and a neutral is available there. Nothing changes on the wall.

At the light fitting or appliance

In many homes the neutral is present at the ceiling rose or light fitting but not at the switch. In that case the relay can go at the fitting, for example in the ceiling void or a junction box, provided the electrician can make it accessible and keep it within its stated operating conditions. The wall switch is then rewired as an input to the relay.

A third option, for compatible Sonoff models (Basic, RF, Pow/Pow R2, TH10, TH16, Dual and G1), is to mount the relay in an electrical panel using the Sonoff DR DIN rail bracket (from AED 10). This is a job for an electrician working in the distribution board, not a DIY task.

Neutral wire and box space

Most Wi-Fi relays need a constant supply to keep their radio running, which usually means a live and a neutral at the place where the relay is fitted. Many older switch positions only carry a switched live, with no neutral. Check the wiring diagram on the specific product page or datasheet, and ask your electrician to confirm what is in the box before ordering.

UAE wall switches normally sit in square BS 4662 back boxes (86 × 86 mm plates). The relay has to fit in that box behind the switch mechanism, with the cables, and without being crushed. Before buying, compare the relay's stated dimensions with the depth of your boxes. If space is tight, fitting the relay at the light is often easier.

If you later decide you would prefer to replace the plates themselves, see our Touch Light Switches. Many of these are European or Italian modular formats, so check the box size required for each series before you commit.

Fans, garage doors and water heaters

Fans

A plain on/off relay can switch a fan on and off. Do not use a dimmer relay such as the Mini-Dim on a fan motor unless the manufacturer explicitly says this is supported, because light dimmers are not designed for motor loads. Speed control normally stays with the fan's own controller.

Garage doors and gates

Many garage door and gate controllers have a push-button input that expects a potential-free (dry) contact. The Sonoff Mini-D is a dry-contact relay. Check the opener's manual to see what input it expects, and check whether the relay can give a short pulse rather than staying latched. To know whether the door is actually open or closed, add a contact sensor from our Smart Sensors range.

Water heaters and heavy loads

Water heaters, pumps and similar appliances draw far more current than lighting. Only use a relay whose rated current and load type are clearly sufficient for the appliance, as stated on its product page or datasheet. If in doubt, your electrician may recommend a suitably rated contactor controlled by the smart relay.

Blinds and shutters

For Somfy io motors, the Somfy Izymo IO transmitter (from AED 326) turns an existing wall switch into a wireless control for lighting, roller shutters, blinds and TaHoma scenarios.

Energy monitoring relays

Some relays measure how much power the connected load uses. Of the relays listed here, the Sonoff Mini-Dim includes energy monitoring. That helps you spot lights left on or compare usage over time. Check the product page to see what the app actually reports before relying on it for a specific purpose. If you want several devices in one app alongside Zigbee products, a hub from our Smart Hubs range may be needed, depending on the system.

Safety: when to call an electrician

• Always for anything connected to fixed mains wiring: switch boxes, ceiling fittings, junction boxes and distribution boards.
• The work must follow your local authority's rules, such as DEWA in Dubai, ADDC/AADC in Abu Dhabi or SEWA in Sharjah.
• Make sure the relay's rated voltage suits the UAE supply, which is nominally 230 V / 50 Hz, and that its rated current suits the load.
• Tenants: the unified Ejari tenancy contract does not allow modifications without the landlord's written approval. Get that approval before any wiring change, even a hidden one.