Which device for 3 phase power line on/off

    • Autor

    Hi all,

    In my new house, I'm going to have a 3 phase "power" group in my breaker box, that I will use to connect a 10kWh sauna heater.

    I would like to be able to automate turning this on/off using some smart home solutions, either with the Shelly app or Home Assistant.

    Which Shelly device would be the most suitable for achieving this function? As far as I can tell, all Shell Pro devices are 1 phase only.

    Welcome to the forum!

    Would recommend a Shelly 3EM with the ability to measure total energy consumption for 3 phase with its current clamps and a 3 phase contactor to control the heater. This contactor can be activated with the additional output (terminals I and O) of the Shelly 3EM.

    „Habt Geduld. Alle Dinge sind schwierig, bevor sie einfach werden!“ (aus Frankreich)

    „Nothing in life is to be feared, it is only to be understood.“ (Marie Curie, 1867-1934)

    „Es reicht nicht“, rief Schiller, „Gedankenfreiheit zu fordern, man muß auch denken können, sonst fordert man Gedankenlosigkeitsfreiheit und die ist die Freiheit zur Dummheit, welche wiederum die schlimmste Unfreiheit überhaupt ist!“
    (Aus „Besuch aus Weimar“ von Gert Heidenreich, Schriftsteller, *1944 in Eberswalde)

    Most 3 phase contacters only need a single phase supply to operate the coil, so pretty much any of the shelly switch devices will be capable of controlling the contactor, the power being used by the sauna heater is going to require a suitable contactor/relay to switch it, which will need to be fitted either in the switchboard, after the circuit breaker, or external to the switchboard, possibly close to the sauna area.

    Depending on the country you are in, there may be other specific requirements for some sort of manual switch /isolator close to the sauna.