Light Wiring Diagrams

Old multi-point radial lighting diagram using junction boxes

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.

N.B. The diagrams below shows the old cable colours as you are unlikely to find this approach taken in a modern property which would use the new ‘harmonised’ cable colours.

If your lighting circuit has all the cables terminate in ceiling roses rather than junction boxes, please refer to one of the following instead:

Multi-point radial lighting circuit with new cable colours (harmonised) or

Multi-point radial lighting circuit (old cable colours)

Multi-point radial lighting circuit using junction boxes

Fig 1: Multi-point radial lighting circuit using junction boxes

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.

Junction box wiring for looped radial lighting circuit

Fig 2: Junction box wiring for looped radial lighting circuit

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.

Junction box termination for the end of a radial lighting circuit

Fig 3: Junction box termination for the end of a radial lighting circuit


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Multi-point radial lighting circuit (old cable colours)

If you are new to lighting circuits, this is a good place to start. Here we will explain how the most common lighting circuit works then we’ll move on to some variations that you may see in your home that may appear to differ from this.

N.B. The diagrams below shows the old cable colours. If the cables in your circuits are Brown and Blue please see Multi-point radial lighting circuit – new cable colours.

Fig 1 shows what is referred to as a radial circuit (sometimes called a ‘loop-in’ or ‘multi-point radial lighting circuit’).

multi point (loop-in) radial lighting circuit

Fig 1: multi point (loop-in) radial lighting circuit

The live feed from the Consumer unit (fuse board, shown in blue in Fig 1) feeds into the first ceiling rose (ceiling rose A, Fig 1). This would be cable A in the diagram below (Fig 2) which shows how the ceiling rose is terminated. This live feed now loops back out of the rose (cable B, Fig 2) and feeds power to the next ceiling light in the radial circuit (Ceiling rose 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 ceiling rose B (Fig 1), This is Cable A in the diagram below (Fig 3), which show how the last ceiling rose in the circuit is terminated.

Ceiling rose (old cable colours)

Fig 2: Ceiling rose (old cable colours)

Notice that each of the three ceiling roses in Fig 1 has, in addition to the power feeds, an additional cable that feeds down to the light switches (the switch wire). This the Cable C in fig 2 & Fig 3.

Radial circuit last ceiling rose (old colours)

Fig 3: Radial circuit last ceiling rose in the circuit (old colours)


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Multi-point radial lighting circuit (new cable colours)

If you are new to lighting circuits, this is a good place to start. Here we will explain how the most common lighting circuit works then we’ll move on to some variations that you may see in your home that may appear to differ from this.

N.B. The diagrams below shows the new (harmonised) cable colours. If the cables in your circuits are Red and Black please see Multi-point radial lighting circuit – old cable colours.

Fig 1 shows what is referred to as a radial circuit (sometimes called a ‘loop-in’ or ‘multi-point radial lighting circuit’).

multi point (loop-in) radial lighting circuit

Fig 1: multi point (loop-in) radial lighting circuit

The light wiring diagram shows how the live feed from the Consumer unit (fuse board, shown in blue in Fig 1) feeds into the first ceiling rose (ceiling rose A, Fig 1). This would be cable A in the diagram below (Fig 2) which shows how the ceiling rose is terminated. This live feed now loops back out of the rose (cable B, Fig 2) and feeds power to the next ceiling light in the radial circuit (Ceiling rose B, Fig 1). This repeats for each light in the circuit until we reach the last light.

Ceiling rose (new harmonised cable colours)

Fig 2: Ceiling rose (new harmonised cable colours)

Once we reach the last light, you can see that there is only The feed from ceiling rose B (Fig 1), This is Cable A in the diagram below (Fig 3), which show how the last ceiling rose in the circuit is terminated.

Notice that each of the three ceiling roses in Fig 1 has, in addition to the power feeds, an additional cable that feeds down to the light switches (the switch wire). This the Cable C in fig 2 & Fig 3.

Radial circuit last ceiling rose (new harmonised colours)

Fig 3: Radial circuit last ceiling rose in the circuit (new harmonised colours)


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