wiring a spur

[jandrews]

when wiring a spur from a 32 amp ring main do i use 2.5mm or 4mm cable?
surely if i used 2.5mm then plugged in two 3kw items, asuming the spur is a 2 gang socket,this would overload the cable?
If i used 4 mm cable then could i have two, 2 gang sockets?

Thanks James