During the AM2 exam you will be presented with 3 already mounted sockets and a fused connection unit which will have to be wired in a ring circuit with the exemption of one of the sockets which will have to be wired as an un-fused spur from one of the other sockets.
To do this simply follow the diagram below.
You will be required to use 2.5mm2 single core cables which must be placed in to the middle part of the compartmental trunking.
The wiring is really simple. You will start in the CU with 3 lengths of single core cables (brown, blue, yellow-green) from the protection device to the nearest socket. From here you will continue to the next unit which is the fused connection unit. From here to the last socket and from there back to the protection device in the CU. After this you will have to connect another length of 3 single core cables from one of the sockets to the IP rated socket which will be your spurred socket.
Taken from: 13A Socket Outlet Ring Circuit (AM2 Exam) | -----------.co.uk - http://www.-----------.co.uk/AM2-Exam-13A-Ring-Circuit.php
An from what I remember is the same as when my apprentices did it a few years ago.
Cable size, is important. As it is in singles, they have specified 2.5mm for all three conductors.