3. One ceiling lamp is imported and does not have an earth cable although it is metal. Is it enough to just connect a cable from the earth wire of the rose to the metal hull of the lamp? The cables of the lamp don't look double insulated and there are no additional information or labels, it looks like this:
But it is not unusual to have more than the standard three sets of cables on a loop-in set up. There will be likely other equipment it is supplying that can be taken from the light circuit (fans, wall lights, shaver points, heating controls, security and fire/smoke alarms etc..)
It is extremely wise to earth metallic fittings that are not passed as double insulated.
And yes cables can be extended by insulated connectors, providing the terminal/connection stays within the enclosure and is protected against accidental contact to non-insulated parts.
Ceiling rose looks like it is the end of a loop, with just the incoming live conductors and the switch lines. Very normal, I was expecting more with regards to your original post! The central two browns are the live loop. The two light blues are the neutral loop and the remaining brown is the switch line/live. Green/yellow CPC/earths.
The cable to the metal fitting would not satisfy the requirements for class I metallic fittings.
I also have metal fittings with two core cable and no double square to show double insulated. I swapped the standard ceiling rose for a type with slide in hook so whole lamp can be wired on the floor the lifted up and slid into position. The hook is earthed but it's unlikely the chain would give good earth continuity. So I have just taken a chance. I think any fault will likely trip the RCD. Also the cable is double insulated i.e. a sheaf on the two wires. The cable you show seems to have no sheaf, so would expect the whole fitting to be earthed.
You have a source the qualified electricians on here. There are number was to make a light work by the operation of a switch. You can loop in both live and neutral in at the light fitting, you can also loop them both in at the swicth, you could alternatively loop just the live in at light and the neutral at the switch or visa-versa.
Then there are other methods using junction box arrangements.
Providing you have a neutral and a switch line at the light fitting and a common/perm live and a switch line at the switch. They will come on/off.
Obviously it would be good/safe practice to have the circuit earthed,
thanks for your answer. I am not sure if I expressed myself well. I do trust the recommendation of the qualified people around here. But I still do not understand the setup and how the wiring should be done. I would like to learn though.
In very amateurish words: I have a lamp that expects three wires, Live, Neutral and Earth. Out of the ceiling come twice as much. As it seems, all of the cables are connected to the light, which means I have to connect several from the rose to just one each in the lamp. What is the rule to do that correctly?
I don't want to just blindly try to copy what I see with the installed light atm, but rather to understand why the cables are connected the way they have to.
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