Controlling mains (230 V) supply up to 5/10 amps using Arduino I am looking for a simple, low cost solution to control on/off of mains supply to certain equipment. The control will be done using one of the output pin of Arduino Uno.

The input trigger and how to control it is application dependent.  e.g. controlling an equipment or controlling supply to section of home but in principle mains control module implementation remains same. So looking for solution which is safe while doing connections as well as while in use in  indoor conditions for years.
The PowerSwitch Tail 2 is a great way for experimenters to control mains voltages. It is insulated and internally decoupled, so you only have to hook up 5v, gnd, and a signal line to control it. 

This model supports only 120V, but there are also kits for 230V.



image from sparkfun