What relay do i need to control 220v 16amp motor (water pump)?
You must be careful when choosing the relay. Firstly, it must be appropriate for the your circuit power supply. For Ex. if your power supply is 5V DC, then you have to choose one which its supply voltage is 5V DC. Secondly,its contact current must be appropriate for the your load current (water pump). My sugggest is that you should choose min. 20A and over one in your circuit.

And I have attached an circuit about your question, you can connect a pump instead of the ac bulb.







simulate this circuit &ndash; Schematic created using CircuitLab