HM79,
Are you talking about radar separation, in which case it does not matter what type of aircraft it is, or wake turbulence separation?
In the UK, A380 followed by;
i) A380 is 4nm,
ii) Heavy (747, 777, 340, 330) is 6nm,
iii) Medium (757, 737, A320 family) and is 7nm.
and so on.