Can anyone tell me how i can switch a voltage of 230 using a low voltage supply?

I am an electrician by trade but I also have some electronic background. I don't know that much about electronics though but I need a simple circuit that can help me switch 230v using a low voltage supply (I would like the supply to be run from the same place - so the low voltage run from a transformer from the 230v supply instead of a battery). Thanks.