A double socket's max load is rated to draw 20A (it can draw 26A if two 13A appliances are plugged in). On a ring that is say a 20A thru that socket and that point on the ring. As I wrote that is one point off a final ring. A 16A MCB, is one point off a final ring, drawing less than a common double socket on a ring. So to those who say a ring only takes 13A, not so. Even with no 16A MCB off a ring, far more than 16A can be drawn from one point.