Fig 1 shows what is referred to as a radial circuit (sometimes called a ‘loop-in’ or ‘multi-point radial lighting circuit’). which uses junction boxes instead of ceiling roses. You may find this wiring arrangement in older properties.
If your lighting circuit has all the cables terminate in ceiling roses rather than junction boxes, please refer to one of the following instead:
The live feed from the Consumer unit (fuse board, shown in blue in Fig 1) feeds into the first junction box (junction box A, Fig 1). This would be cable A in the diagram below (Fig 2) which shows how the junction box is terminated. This live feed now loops back out of the junction box (cable B, Fig 2) and feeds power to the next ceiling light in the radial circuit (junction box B, Fig 1). This repeats for each light in the circuit until we reach the last light.
Once we reach the last light, you can see that there is only The feed from junction box B (Fig 1), This is Cable A in the diagram below (Fig 3), which shows how the last junction box in the circuit is terminated.
Notice that each of the three junction boxes in Fig 1 has, in addition to the power feeds, an additional cable that feeds down to the light switches (the switch wire). This is Cable C in fig 2 & Fig 3. Cable D (Fig 2 and Fig 3) is the feed to the light fitting.