How to wire a ceiling light?

Question

At the switch I have Red and Black at the ceiling rose I have 2 blacks one with yellow sleeving. Why?

Answer 1

Red and Black are going to be the same in the curcuit, wat is called the hot lead or hot wire.
The switch just breaks the curcuit or acts as a gate, when the switch is off, the gate is open and no electricity can flow any further. But when the gate is closed the curcuit is completed, electricity flows, and the light comes on.

Up at the light, coming out of the ceiling, the black is going to be the hot lead, properly refered to as the switchleg because this wire is coming from the switch.
the black with yellow should be the nuetral wire in the curcuit which will go back to the panel where your curcuit breakers are located, which by the way is always recomended to be in the off position for the specific curcuit you are working on. Else sparks may fly and bites could be felt.
This nuetral wire allows the electricity to return to the source.

Some FYI - in most all modern day wiring, for the nuetral, white will be used, if not white then blue, alot of electricians will steer away from using yellow because in a case were you have a three phase panel yellow is commonly used to refer to or indicate a hot lead.

However, as long as the stated information you gave is correct, in that you only have four wires "At the switch I have Red and Black at the ceiling rose I have 2 blacks one with yellow " is correct, then what is stated above will apply, and as long as no half-assed fuqtard did the wiring in your house.

added links
http://www.diydoctor.org.uk/projects/lights_and_switches.htm

http://www.electrical-online.com/basiclightswitchwiring1.htm

Answer 2

One of the blacks in the going down to the switch on the wall. This even sounds like this light is controlled by two different switches. (3 way switches, maybe in a hall or down some steps.) The black wire might be the power leg, the black w/yellow sleeve could be your switch leg coming from the power down to the switch. But you will have to find out for sure. Test the wires, with a wire tester. inexpensive tool to own.

Answer 3

Are you in the UK? Are there ONLY 2 blacks with one sleeved yellow at the rose?? Are there no reds in or behind the rose??

I suspect that there are at least two reds joined behind the rose, if so the black is ALMOST certainly the neutral and the yellow sleeved black is the switch wire from the switch. Re-sleeve this core with red/ brown tape/sleeving to identify it properly, do the same to the black at the switch.

Answer 4

Please call an electrician. This is no job for an amateur and it is now illegal to do such work unless it is checked by a qualified electrician.