One of the most prevalent electrical wiring systems for lighting circuits today is the ‘loop-in’ system so that one will be tackled in this article. The lights and their switches are run in a chain from the consumer unit (CU), or fuse box in older houses, using the ceiling rose as a key junction of the circuit as well as a means of supplying switched electricity to the central light fitting.
There is another popular method used when electrical wiring is being laid as a house is being built, called the junction box method. This is where the job of the ceiling rose is replaced by a junction box in the ceiling cavity above the rose. In this instance the ceiling rose then becomes a very simple connector and anchor point for the lamp flex so we will not cover that method in this article.
DIY Wiring – Assess Your Level of Competency
There are some important points to make about DIY electrical wiring. The first is to be realistic about your level of DIY skills and wiring knowledge and be sure that you should really be doing this, rather than getting a qualified electrician in to do the job.
The second is to ensure that the supply to the electrical wiring is cut off at the CU. There will usually be a separate lighting circuit for each floor of a house, although older and more rambling houses could be divided up in any of a number of ways. Note that turning the supply off at the switch is not good enough.
The third is to be sure you understand the electrical wiring that is installed in your house, particularly if you are adding a ceiling rose as opposed to just replacing one.
Simple Ceiling Rose Replacement
Of course, if you are just replacing a ceiling rose you can simply unscrew the cover, detach the light cord at the terminals and at the flex supports, drawing a diagram of the way they were connected as you go. Then make a note on the diagram of the electrical wiring connections in the old ceiling rose. Install the new one and simply remake the connections exactly as in your diagram.
As long as you are not making any other changes to the electrical wiring system, once you reconnect the lamp flex it should all work as before.
Loop-In Electrical Wiring – What Goes Where?
If you don’t have that luxury, let’s start from scratch with wiring a ceiling rose with the ‘loop-in’ system. Connect the live wire supplying current from the CU, or the previous ceiling rose in the circuit, to the central block of connectors (there will be three blocks). Connect into this block the live wiring taking the power to the switch and to the next ceiling rose in the circuit (unless it is the last one, in which case there won’t be one) as well.
The outer block of three terminals will take the neutral wires that correspond to the live wires you connected into the central block, leaving the outermost one for the flex cable. Similarly on the pair of terminals on the other side the outermost one should be left blank for the flex. The other one should take the wire coming back from the light switch.
The earth core at the centre of the cable should be sheathed in green and yellow tubing and connected to the earth terminal on one side of the ceiling rose.
Connecting the Lamp Flex
Once everything is connected up, connect the lamp flex into the two terminals that were left free at either end of the run of connector blocks. If there is an earth conductor in the flex then join it to the earth terminal in the ceiling rose. Also make sure that if there are any supporting lugs in the ceiling rose that the flex conductors are wrapped around them to take the load off the screw posts of the brass terminals.
Don’t forget to put the flex through the hole in the centre of the cover of the ceiling rose before making the connections, unless the lampholder is to be connected later on. Screw the cover back up, switch the circuit back on to test and hopefully everything will be work properly.
Safety First With DIY Wiring
One final word about electrical wiring colour systems. The twin-core and earth wiring used in lighting circuits was colour coded red and black in the UK for many years but in recent times we have fallen into line with the continental system endorsed by the EU. This has brown for live and blue for neutral, in line with the power and lamp flexes we have been seeing in the UK for the last thirty or forty years.
If you are in any doubt whatsoever as to which electrical cable is which, do not touch anything and call in an electrician.