A 3A supply will only provide about 700W of power. That's fine if you simply want to plug in your radio or mobile phone charger (or anything else which only requires a few watts). However, if you plug in an electric kettle (which typically consumes around 2200W), the circuit will be overloaded and trip out.
A 5A supply will provide around 1150W. You can plug in a few more appliances (or appliances which require more power) but your 2200W electric kettle will still cause the circuit to trip.
A 10A supply will provide 2300W. You can plug in a 2200W kettle without the circuit tripping but you'd be unwise to have anything else (except possibly something like a phone charger) plugged in at the same time.
To decide which hook up you require, take a look at the labels on the electrical equipment you intend to use. (All electrical appliances should carry a label stating the power rating. Remember that there are 1000W in 1kW, so a kettle might be labelled as 2.2kW, rather than 2200W). Note that some electrical appliances (e.g. 'fast boil' kettles) use up to 3100W (= 3.1kW). You won't be able to use such appliances, even with the 10A hook up.
Chris