Smart relay

The universal, smart control option for your electrical devices – both flexible and convenient

The most flexible solution for smart switching

The smart switching relay is your universal all-rounder for smart switching: Garage doors, smart irrigation systems, ventilation systems, pumps, lighting or conventional sockets – the range of possible uses is virtually limitless.

Multifunctional use

The smart relay uses potential-free contact for switching a range of electrical devices – e.g. garage doors, pumps, garden irrigation systems, (gas) boilers, ventilation systems, sockets and lighting.

Flexible installation

The Bosch Smart Home relay is flexible to install behind existing wall switches and buttons or in junction boxes – and even outdoors in weatherproof installation boxes (e.g. IP66).

Individual operation

You can control the smart relay in a number of different ways – using the connected wall switch/button, by voice, using custom scenarios, automations and time programs, as well as remotely via app.

Installation

The smart relay is quick and simple to install by following the step-by-step instructions in the app.

Please note: 230 V AC devices must be installed only by authorised, qualified persons.

The smart relay works in a similar way to conventional switches: It breaks the circuit – but in this case remotely. There are two different usage modes to facilitate a range of applications.

Mode 1: On/Off

The first option is “On/Off” mode.

“On/Off” mode: The device behaves in a similar way to a rocker switch. You can actively switch devices on/off using the connected switch, voice commands or the app, or alternatively use schedules or automations to switch them.
Application area: Devices that are generally operated using a (rocker) switch, such as smart irrigation systems, ventilation systems, pond pumps, (gas) boilers, sockets, lights, etc.

Mode 2: pulse control

The 2nd option for smart switching with the Bosch Smart Home relay is “pulse control” mode.

“pulse control” mode: In this mode, the device behaves like a button. The circuit is briefly closed and the connected devices react to the short current pulse. A good example of this is stairwell lighting.
Application area: Devices that are actuated directly via a button (e.g. garage door openers) or are connected to a central pulse relay (e.g. automatic stairwell lighting).

Voice assistants

“Alexa, switch on the sprinklers.”

You can control selected functions of the smart switching relay conveniently by voice command using Amazon Alexa, Google Assistant or Siri.

In addition, the fact that it can be integrated into Apple HomeKit®, Amazon and Google Home allows it to be combined with compatible devices from other manufacturers.

Repeater- & Schutzfunktionen

Enjoy additional safety thanks to the following integrated safety features:

Overheat protection: Constantly monitors the device temperature, switches it off automatically in the event of overheating and informs you via the app.
Child lock: Enables you to disable manual operation of the wall switch/button – quickly and simply via the app.

A handy side effect of your smart relay is that it automatically boosts the wireless signal of certain devices in the Smart Home system that use the ZigBee wireless standard, thereby acting as a Smart Home repeater.

Important notes & useful information

Important information and requirements for installation

The smart relay can be used with AC consumers up to 2990 W (observe type plate: capacitive/inductive up to 400 VA) as well as DC consumers up to 24 V at 8 A.

Thanks to its compact design, the relay can easily be used in junction boxes. If needed, you can also connect a conventional mechanical switch to the relay to allow you to operate it manually. A wall switch/button is not required if the relay is installed in a junction box.

The device can be used for smart switching of lamps/lights and other electrical consumers.

Please note the following:

Compact size of 40.5x47x22 mm (HxWxD)
Fits in standard in-wall sockets with a depth of at least 50 mm as well as standard surface-mounted sockets.
May only be used outdoors with suitable protective housings (e.g. IP66).
A depth of at least 50 mm is required for installation in in-wall sockets. For optimum installation, a socket depth of over 60 mm is recommended.
The relay requires a constant 230 V power supply with a conductor and neutral conductor.
The screws of the connection terminals should not be unscrewed completely in order to ensure a firm fit of the screw after installation.
Installation must be carried out only by authorised specialists.

Installation with a wall switch Installation with a junction box Installation with a socket

Connection diagrams

Caution! 230 V AC devices must be installed only by authorised, qualified persons.

Make sure that you switch off the circuit breaker before starting work!

Connection diagrams

The Bosch Smart Home relay requires an AC power supply of 230 V/50 Hz for operation.

However, the potential-free output means that connected circuits can be operated with direct current or alternating current within the limits specified in the data sheet

(AC: max. 230 V / 13 A, DC: max. 24 V / 8 A)

To connection diagram

Caution! 230 V AC devices must be installed only by authorised, qualified persons.

Make sure that you switch off the circuit breaker before starting work!

Accessories for ideal installation

The device does not fit together with your switch in the device box?

Our wall switch is an accessory that enables you to install your Bosch Smart Home actuators in a space-saving manner. The integrated adapter means that the rocker and frame supplied can also be replaced with covers from common switch series.

The extra flat design and integrated mounting aids for the cables and the module facilitate compact installation from an installation depth of 30 mm.

The switch has two button outputs, allowing it to be used for the light/shutter control II as well as for dimmers or relays with only one output each.

Available from the second half of 2024

Other actuators in the Bosch Smart Home system

Are you familiar with our other smart actuators?

Smart light control: Makes your conventional lighting smart
Smart shutter control: Makes conventional shutters, Venetian blinds and sun blinds smart
Smart dimmer: For smart control of your dimmable lighting

Applications

Make your garage door smart

A popular application area for the Bosch Smart Home relay is as a smart garage door opener.

Do you open your garage door manually using a switch and by remote control? With the smart relay, you can make your garage door smart and thus

open and close it using the app or voice commands.
When used in combination with the door/window contact II (plus), you can see whether the garage door is open or closed at any time, no matter where you are – and be reminded to close it if necessary.
Integrate your garage door into Smart Home automations or scenarios. Example:
IF you activate your “Leaving home” scenario AND the door/window contact II (plus) on the garage door signals that it is still “open”, THEN close the garage door.

Create a smart irrigation system

Switching the lawn sprinklers on and off manually is a thing of the past! With your smart relay, you can make your garden irrigation system smart. Simply install it in a weatherproof installation box (e.g. IP66) and you can:

Control the irrigation system by app or voice.
View the status of the smart garden irrigation system at any time.
Integrate your lawn sprinklers etc. in scenarios or automations. Example: IF it is sunrise, THEN switch the smart garden irrigation system on AND switch it off again after 30 minutes.
Switch the garden irrigation system on and off automatically using a time program, which can be set individually for each day of the week.

Make your sockets smart

The Smart Home relay is one of two ways to make traditional electrical appliances smart:

Option 1 – the flexible, moveable variant: Plug the smart plug compact into the appropriate socket to give you smart control of the power supply to the connected devices.
Option 2 – the space-saving variant: Install the smart relay discreetly behind the socket to give you smart control of the power supply. This is also particularly practical for sockets that are hidden behind cupboards and sideboards.

Thanks to the integrated switching relay, you can now control the socket flexibly: when on the move, via the app or in the conventional way using the switch, using voice commands or a timer, as well as with custom scenarios and automations.

This also helps to save energy: Simply cut off the power supply to stand-by devices automatically at bedtime or when you leave the house – thus relieving the strain on the environment and your wallet.

Make the ventilation system in your new build smart

Your ventilation system provides fresh ambient air on a time-controlled basis – but wouldn’t it be handy to also be able to react spontaneously to poor air quality?

The Bosch Smart Home relay can make ventilation systems smart. All you need is a switch input for external control. Simply install the switching relay here and take advantage of the flexible control options, using the app, voice commands or automation.

Pro tip: Have your smart ventilation system switch on automatically as soon as your Twinguard measures an insufficient air quality value – until the value is back in the optimum range.

Making your (gas) boiler and electric heating smart

Your relay can also assist you with smart heating: The smart relay allows you to control your (gas) boiler or electric heating via app and using the room thermostat.

Make your (gas) boiler smart:
Simply connect the Smart Home relay to your central heating system and select “Boiler” as the purpose of use. You will then be able to switch the (gas) boiler on/off using the app or room thermostat.
Make your electric heating smart:
Connect the switching relay to the electric heating (e.g. infrared heating) and select “Electric heating” as the purpose of use. This will enable you to switch the heating on and off remotely via the app.

Buy now

Smart Home Relay

Multifunctional switching of electronic devices through potential-free contact (e.g. compatible garage doors, ventilation systems, pumps, sockets and lighting)

Multiple control options e.g. via app, using switch/button, scenarios, automations, time programs

Option to control selected functions via voice assistant (Amazon Alexa or Google Assistant)

Discreet installation behind switches/buttons, in junction boxes or weatherproof installation boxes (IP66)

Acts as a repeater to extend the wireless signal range of certain Bosch Smart Home devices

Can only be used in combination with the Bosch Smart Home controller or Bosch controller II

62.07 GBP

* Including 20% VAT

Further information

Technical Data

Device type designation

BMCT-RZ

Part Number

8750002082

EAN

4062321596002

IP code

IP20

Protection class

Device protection

Thermal cutoff

Ambient temperature

– 20 °C … + 50 °C

Dimensions (W × H × D)

40.5 × 47 × 22 mm

Weight

40 g

Radio frequency band

2.4 – 2.4835 GHz

Radio protocol

ZigBee 3.0

Max. transmitting power

10 dBm

Radio range in the open

< 70 m

Software class

Receiver category

Supply voltage

230 VAC/50 Hz

Power consumption in sleep mode

< 1 W

Cable type and cross section

Rigid and flexible cable, 0.75 – 2.5 mm²

Box contents

1 Smart Home Relay BMCT-RZ

1 user manual in 11 languages

Manuals

Smart Home Relay: download manual as PDF

Download now

Bosch Smart Home App

Download the Bosch Smart Home App in your Apple App Store or Google Play Store.

System requirements

Often used together

Smart Home controller II

This is needed in order to use your Smart Home relay and connect it to your app and other devices in the Smart Home system.

Smart Home controller II

Twinguard

Ventilation system made smart thanks to the relay? The Twinguard continuously measures the air quality and automatically increases the ventilation if values are poor.

Twinguard

Door/window contact II (plus)

Garage door opener made smart with the relay? The door/window contact II (plus) enables you to see whether the door is open or closed from anywhere at any time.

Door/window contact II (plus)

Light control II

Make your lighting smart and control up to two circuits independently of one another? Light control II makes it possible!

Light control II

Shutter control II

Make your shutters, Venetian blinds or sun blinds smart? Shutter control II controls the position and tilt of your shading.

Shutter control II

Smart plug compact

Make traditional electrical devices smart – and be able to switch sockets spontaneously? The smart plug compact makes it possible.

Smart plug compact

Room thermostat II

Precise heat regulation for smart radiator thermostats – ensures the optimum temperature in a room and easy operation.

Room thermostat II

Dimmer

Allows smart dimming of non-smart dimmable lights – and is thus an alternative to installing smart lights invisibly in the wall.

Smart dimmer