Shelly 2.5 with 220v coming in two phase each of 110v

  • Hi,

    How do I connect Shelly 2.5 in a two phase 110v resulting in 220v ? It' a relay for a power outlet that expects 110v coming also on both wires going to it.

    I thought of connecting both to the both L connector and the output to 01 and 02. There is no neutral in this case.

    Issues that I foresee:To turn it on, I'll have to turn on both switches at the same time

    To measure the power usage I'll have to sum both relays.

    Am I doing it right or is there an easy way ?

    Nowadays I use a Sonoff R2 Basic. For it I just connected each wire to input and two to the output, no neutral need in this case since both carry power. I want to change it to be able to also measure power usage of that outlet

    Thanks for any input

  • At first, some questions:

    The power outlet shall be suited to connect 220V consumers only?

    Would it be necessary (by rule in your country) to switch both wires of the power outlet? Or is it sufficient to switch off one live wire only?

    Why do you assume you’ll need a Shelly 2.5?

    What power does the device(s) consume connected via the power outlet?

    Many thanks for some hints to your plan!

    „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)

  • Thanks for your reply.

    I just bought the Shelly 2.5. I thought it will work with most of my things and it has power measurement. This is the only case I have for 220v. It has a motor that pressurizes the water. It turns on every time a faucet is open, but in the quiet of the night having it turning on and off is kind of annoying, so I turn it off at 11:00 pm and on at 7:00am.

    Since I have sonoff basic R2 and it handles 10A, I guess 10A is what it needs. I don't have the specs of the motor.

    About the power... Yes, in my country (Brazil) when you have 220v typically you would need to phases coming on both wires, so you have to add 2 x 110v. Regarding powering it off... some devices might still work, but with less potency, it can also break the device. I don't have a problem if I had to switch off both at the same time.

    One thought that just occurred me is maybe I can join both 110v cable at one L input, use one O as output for two cables that goes to each pole of the outlet. The issue is the neutral.... And both wires together may cause a short circuit.

    I'm by no means a electrician or electrical engineer, I'm just a curious homeowner...

  • Unfortunately , none of my questions was really answered…

    Despite this, I would give some hints:

    (a) Connecting a Shelly with two phase 110V network was discussed here:

    thgoebel
    15. März 2022 um 20:01

    Although it was not a Shelly 2.5 (but a Shelly pro 4PM), the fundamental principle is clearly demonstrated: One the live wires (let‘s call it L1) has to be connected with terminal L of Shelly 2.5. The other live wire (L2) has to be wired to terminal N of Shelly and to one pole of the power outlet. Terminal O1 (the switched live wire L1) should be connected to the other pole of power outlet.

    (b) A Shelly 2.5 is NOT very suited for this application! Due to its very dense innards it will likely overheat if high current passes. Using a Shelly 1PM or Shelly plus 1 PM would be much better…

    (c) You should place a two pole manual switch in the loop to allow a secure off state in case of servicing the pump!

    (d) I would recommend seriously to call the support of a local electrician! Your life and the life of your relatives deserve this precaution!

    „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)