Lighting Circuits:Ceiling Roses

Ceiling Roses

There are basically two types of ceiling rose available, although there is a wide range of makes and shapes. The two types are the Two-Plate Ceiling Rose, which has two terminals and the Three-Plate Ceiling Rose, which has three terminals. Both were developed for use on different wiring systems. Older types of ceiling roses were developed at a time when it was not necessary to provide an earth at lighting points. It is now essential to provide an earth, and so an earth terminal is now included on all ceiling roses. This in effect means that a Two-Plate Ceiling Rose has a third terminal fitted, whilst a Three-Plate Ceiling Rose has four terminals.

Figure 20 illustrates one of the original types of Two-Plate Ceiling Rose. The earth terminal is marked “E” and the two unmarked terminals are used for the neutral and the switch wire. There must also be a cord grip provided similar to that in a lampholder.

Figure 21 illustrates a Three-Plate Ceiling Rose. The additional terminal, marked L, is for the Phase or ‘Live’ conductor, which is present in a lighting system wired using the Three-Plate Ceiling Rose Method.

Figure 22 illustrates a modern type Three-Plate Ceiling Rose which has been designed to minimise installation time, and maximise safety of the installer and the end user. Each of the four terminal blocks have three individual terminal screws. It caters for the connection of twelve conductors.

Figure 23 illustrates a lampholder connected to a ceiling rose. The complete unit is called a pendant. The flex connecting the lampholder to the ceiling rose should be a minimum of 0.5mm2. Heat Resisting White Circular PVC type is recommended.

Pendants are available from certain manufacturers in a range of flex length. This allows installations to be completed more efficiently.

Figure 24 illustrates a plug-in type ceiling rose and safety lampholder, which can be easily removed without leaving exposed conductors. The safety lampholder incorporates contacts, which are automatically disconnected from the supply, when the lamp is removed.