Buying Guide: Intermediate Switches & Smart Relays

Buying Guide: Intermediate Switches & Smart Relays

Whether you simply want to repair your old table lamp or make your home lighting smart without changing the design of your switches, the in-line switches category offers the most practical and affordable solutions.

What Are In-Line Switches?

In-line switches are devices placed between the power supply and a light fixture or electrical appliance, allowing you to turn them ON or OFF directly. In their traditional form, they are the classic cord switches found on table lamps and floor lamps. Smart versions include either Wi-Fi/Zigbee cord switches or small recessed relays hidden inside the wall junction box, allowing you to control lights, appliances or electric shutters from your phone or with voice commands, without changing your home's existing switches.

  • Standard In-Line Switches: Classic mechanical cord switches for table lamps, desk lamps and floor lamps. They offer simple, reliable ON/OFF control without the need for internet, apps or batteries. 
  • Smart Switches / Relays (In-Wall Modules): Small recessed modules that are hidden inside the wall junction box, directly behind the existing wall switch. They let you control lights, appliances or electric shutters smartly while keeping your favorite switch buttons intact.
  • Smart Buttons / Remote Controls: Wireless battery-powered buttons that can be mounted or stuck to any surface, serving as portable switches for instantly activating automations and lighting scenes.
Buying Guide: Intermediate Switches & Smart Relays

Which type is right for your installation?

Before you buy, the most important question is where it will be installed: externally on the cable or recessed behind the wall?

A. Classic Inline Cord Switch (Mechanical)

The traditional, reliable solution for table lamps, desk lamps or floor lamps. It’s easy to install by cutting into the external cable and works with a classic ON/OFF button. No Wi-Fi, apps or batteries required.

B. Smart In-Wall Relay (In-Wall Module)

The most elegant solution for a smart home. These small modules are concealed inside the wall box, directly behind the existing wall switch. You can keep the original switches that match your home’s décor while gaining full remote control.

C. Smart Buttons (Wireless Automation Buttons)

Smart Buttons are the most practical solution when you need a physical switch in a location with no electrical wiring, such as on a bedside table, coffee table or next to the entrance. They run on a battery (which often lasts more than 1–2 years), can be attached anywhere with double-sided tape and recognize different presses (single, double or long press). This means that with a single button, you can switch a light on and off, adjust its brightness or activate complex scenarios throughout your home (e.g. a “Sleep Scene” that turns off all the lights and lowers the roller shutters at the same time).

Popular options:

  • Sonoff SNZB-01P Smart Button ZigBee – an extremely affordable and reliable Zigbee button, supporting 3 different actions (single, double and long press) and featuring a magnetic mounting base.
  • Xiaomi Mi Wireless Switch – a top value-for-money choice with a minimalist design, support for 3 actions (single, double and long press) and seamless integration with the Xiaomi Home ecosystem (via Mi Hub).

Buying Guide: Intermediate Switches & Smart Relays

What to Consider Before Choosing

Number of Channels (Gangs)

The number of channels indicates how many independent lights or devices the same unit can control:

  • 1 Channel: For a single light fixture or socket.

  • 2 Channels: Ideal for two-way switches (e.g. in a living room) or for electric shutters/awnings, where one channel is needed to raise them and another to lower them.

  • 3 or 4 Channels: Typically used for larger installations, chandeliers or DIN rails in electrical panels.

Neutral Wire: Do You Have One?

If you choose a recessed wall relay, this is the most important point:

  • With Neutral: If there is also a blue wire (neutral) in the junction box, the connection is more stable and the device usually also works as a signal repeater (mesh repeater).

  • No Neutral: In most older Greek homes, only the live wire runs down to the switch. In this case, choose relays specifically designed to operate without a neutral wire (often supplied with a small bypass capacitor that is installed at the light).

Two-Way Switching

If the hallway or stairwell light can be switched on from two different switches, make sure the smart relay supports two-way switching. This allows the light to continue working normally from both wall switches, alongside control via your smartphone.

Power Consumption Measurement & Maximum Load

  • For standard LED lighting, a 10A (~2300W) model is more than sufficient.

  • For devices with higher power requirements (e.g. heaters, water heaters, washing machines), choose a 16A switch.

  • If you want to see how much power each device is using in real time, choose a model with Power Metering (PM).

Buying Guide: Intermediate Switches & Smart Relays

Which communication protocol is right for you?

Protocol Advantages Things to consider Ideal for...
Wi-Fi Connects directly to the router without extra equipment. Adding too many devices may put a strain on your home network. Those just getting started with 1–3 devices.
Zigbee Fast response, minimal power consumption, and a stable mesh network. Requires a central Zigbee Hub (Gateway). Medium and large installations throughout the home.
Matter / Thread Universal compatibility with Apple Home, Google Home, and Alexa. Requires a compatible Matter controller. Investing in next-generation technology without limitations.

Buying Guide: Intermediate Switches & Smart Relays

If the internet goes down, will my lights still turn on?

Yes, absolutely. Smart in-wall relays maintain the physical connection to the wall switch. You can still press the switch to turn on the light, even if the router is completely offline.

Will the relay fit inside my wall box?

Next-generation relays (such as the Sonoff Mini and Shelly Mini) are less than 1.7 cm thick and fit in most standard 40–60 mm-deep boxes. If space is limited due to a lot of wiring, choose models marked “Mini” or “Extreme”.

Is installation safe?

Connecting a simple mechanical cord switch is straightforward, as long as the device is unplugged. For in-wall relays, since they connect directly to the 230 V electrical supply, always switch off the main circuit breaker in the electrical panel. If you don’t have the relevant experience, installation by a licensed electrician is recommended.

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