Mains Radio-Interlinked Thermoptek Alarm with Battery - FireAngel Pro WST-230

It is usually recommended to install an optical smoke alarm in a bedroom. This is because optical smoke alarms are slightly quicker at detecting slow smouldering fires that can originate from upholstery type materials and over-heated wiring. Also, an optical smoke alarm would be less likely to sound a false alarm than an ionisation would, if steam/water droplets were present from the bathroom. Detectors should be installed as central to the room as possible; however for your application I would also consider the position of the en suite to make sure that the detector is not in the direct path of the joining door. This is just to try and avoid the chances of a false alarm. No detector is designed for use in bathroom areas.

In modern housing the lighting circuit will travel around your house with the lights being fed from it. Between the circuit and the light will be a switch (or in this case a dimmer) which will control the light. Your mains powered alarms are connected directly to the circuit and have constant power, so are not affected by switches or dimmers.
In older homes that have not had the electrics updated this may not be the case so it is advisable to consult an electrician.

Safelincs is signed up to Valpak's WEEE (Waste Electrical and Electronic Equipment) Distributor Take-Back Scheme (Registration ID: 7370). Private households can therefore drop off their electronic and electrical fire safety waste at their municipal recycling centre when they are purchasing new products from us. To find your nearest recycling centre, please visit www.recycle-more.co.uk.

Yes, hard-wired mains powered alarms can be wired to the unswitched live feed of the nearest frequently used lighting circuit.

Yes, should the radio interlinking signal fail the units will continue to sound independently should they detect a fire.