A relay for each terminal (live and neutral)
Yes it is normal to switch both poles of a mains circuit. That way, if the circuit is incorrectly wired (or plugged in, where 2-pole plugs are reversible!) you can be certain the circuit is not accidentally live when it is switched off. 

What is NOT normal is to fuse both poles - if fuses are fitted, they should ONLY be in the live circuit, for hopefully obvious reasons.