I bought a relay board (this one) that can handle 10A at 250V, my question is: if I wire a mains supply into it, say from a ring circuit (that powers sockets throughout normal houses). Will the relay be able to handle the current/voltage to work appropriately? (The relay will power device like a computer, tv, monitor, etc...)

  • 2
    \$\begingroup\$ Spend more time describing your concepts and ideas. If needed, reference pictures that illustrate exactly what you have ahead of you. "A relay board" isn't nearly as good as identifying exactly which relay board. Saying "ring circuit" means almost nothing to me, but could be something like a doorbell's AC secondary transformer voltage, for all I know. I've already written more than you, and that's not a good thing when it's a question you care about. (Or should.) \$\endgroup\$
    – jonk
    Dec 3, 2018 at 20:56
  • \$\begingroup\$ @jonk I have edited and showed what relay board I have used \$\endgroup\$
    – MCC
    Dec 3, 2018 at 21:04
  • \$\begingroup\$ @jonk it being a ring circuit is irrelevant to the question (it's a common mains distribution topology used in domestic dwellings in the UK) \$\endgroup\$
    – NMF
    Dec 3, 2018 at 22:59
  • \$\begingroup\$ As NMF indicates, a ring circuit is an indicator you're not in north america, and your system voltage is probably 240V rather than 120V. It would be better if you indicate where you live, and your mains voltage if you know it. The board you show appears to have relays that can switch up to 10A at 250VAC. The board and control mechanisms operate at 5VDC. \$\endgroup\$
    – K H
    Dec 4, 2018 at 4:00

1 Answer 1


You could, actually. You need to keep in mind not to exceed the max current in the relay. Check the nominal current each device consumes. Avoid connecting stuff like hair dryers, toasters, etc.

  • \$\begingroup\$ Yes, the OP 'could', but if they have to ask the question here then they probably shouldn't without significant consideration of the safety implications, protective earthing, fusing etc. \$\endgroup\$
    – NMF
    Dec 3, 2018 at 22:56
  • \$\begingroup\$ @NMF the earthing continuity will be kept through the sockets using crimps or connector blocks. Devices plugged into the sockets will have fuses too so the safety will be managed \$\endgroup\$
    – MCC
    Dec 4, 2018 at 6:43
  • \$\begingroup\$ He could do it, yes. Will it achieve what he wants to do, which I can only guess is to turn devices on or off remotely or based on a timer? Who knows. Many devices such as TVs, monitors and computers power up in standby mode and won't switch on without manual action. And turning a computer off by cutting the mains supply doesn't always end well. \$\endgroup\$
    – Finbarr
    Dec 6, 2018 at 17:10

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