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What voltage and current for electrical switch?

  • 03-02-2018 03:58PM
    #1
    SilverSideUp
    Registered Users, Registered Users 2 Posts: 63 ✭✭


    I'm building a board which uses an electromechanical relay to switch on and off a gas boiler. I'm trying to work out the required voltage and current for the relay. Does this depend on the rating of the boiler which is rated 170W, 230VAC and has a 3Amp fuse? Any help appreciated. Thanks!


Comments

  • #2
    DublinDilbert
    Registered Users, Registered Users 2 Posts: 5,400 ✭✭✭DublinDilbert


    SilverSideUp wrote: »
    I'm building a board which uses an electromechanical relay to switch on and off a gas boiler. I'm trying to work out the required voltage and current for the relay. Does this depend on the rating of the boiler which is rated 170W, 230VAC and has a 3Amp fuse? Any help appreciated. Thanks!

    The contacts on the relay should be able to switch 230V AC min. Your probably not just switching the boiler, your probably switching the circulation pump too. As the pump can have an in-rush current your best to over spec the current rating, 10-15A should be fine.

    The coil voltage for the relay will depend on what you want to drive it from.


  • #3
    SilverSideUp
    Registered Users, Registered Users 2 Posts: 63 ✭✭SilverSideUp


    DublinDilbert wrote: »
    The contacts on the relay should be able to switch 230V AC min. Your probably not just switching the boiler, your probably switching the circulation pump too. As the pump can have an in-rush current your best to over spec the current rating, 10-15A should be fine.

    The coil voltage for the relay will depend on what you want to drive it from.

    Great advice, thank you!


  • #4
    G-Man
    Registered Users, Registered Users 2 Posts: 577 ✭✭✭G-Man


    Are you doing a remote or thermostat switch on and off. ?

    Boilers generally need to be independently powered independent of timer or thermostat and control their own switch off and on, so that they can regulate their cooling. Check the connection diagram from your boiler and recommended thermostat.


  • #5
    SilverSideUp
    Registered Users, Registered Users 2 Posts: 63 ✭✭SilverSideUp


    Thanks. Yes, I studied my Baxi boiler wiring diagram very carefully. The boiler is independently powered. DublinDilbert was spot on, 230V and rated 10-15A.


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