My son has just purchased a new property and has attempted to change the light fitting in the main bedroom. He did not write down the wiring set up when removing the old light fitting and is now left with 3 black cables.
So, having looked at the situation I found that two of the black wires are joined together whilst the other is on its own. I am assuming that the 2 together are neutral whilst the single cable is the live one even though it has no red sleeve on it. Am I right to assume so?
Are there any more cables in ceiling void ie reds, green and yellows.
You usually find Live (red) blacks (neutral/switch) and Green and Yellows(CPC/earths) at this point.
In general all the reds(live) are connected together in a block or in a rose,
the CPC/earths are also terminated together in a block or termination on fitting/rose. They could still be stuck in celing void.
The blacks(neutral) are neutrals terminated on neutral of light fitting at blue flex side.
The the spare black is switch live terminated at live terminal at brown flex side of fitting.
I assume from your description of the problem that you dont need further help with terminals.
Why not mark the switch live black now, so that it is not lost again.
Also, have a look in other ceiling roses, and if 3 plated, mark the switch live, in case of further replacementof fittings
pretty much, if your wrong the worst that can hapen is you'll trip the switch (or blow the fuse), although you may take the switch with it as well.
the best way though is to test your single black for continuity from the switch. if you don't have a tester to check the continuity from the switch to your lonely cable then connect up a standard pendent fitting and see what happens (because thats easier than taking your new light fitting apart again!)
Thanks very much for the invaluable information. I will be at my son's house later today and will connect up a pendant fitting to check the connections. If all is fine I will mark up the switch live cable. Once again thanks very much.