Was trying to replace a light fixture and came to this mess. The two cables (black and blue) were connected to the old light fixture. There was also a ground yellow/green cable that was attached to the old light but when it wasn’t connected to anything on the wall. As far as I can tell the blue neutral cable is tied to about 4 green/yellow. The black live cable seems to be tied to the right black cables but I’m at a loss as to what to do and where to connect the new light. Also where do I ground and should the blue neutral cable be connected elsewhere? Any help would be appreciated!

by Few_Perception4219

5 comments

  1. Not an electrician so take my words with caution, but it seems that “Klassische Nullung” is applied here, there’s no actual separate PE conductor, it’s simply shorted to N. While this is lacking important safety features of a proper PE terminated at a star grounding point, it’s rather common in old buildings. In any case, whenever there’s doubt I’d definitely get professional help.

  2. Electrician here: if you’re absolutely unsure get professional help! BUT be aware that they’ll charge you seriuous money (up to 100€ including driving to your adress etc.) for a very minor job.

    I, personally, would just connect blue to blue, black to black (or brown) on the counter part of the new light just like it was on the old one and be done. PE (green/yellow) not there is what the other person called “klassische nullung” and is old stuff protected by the nice word of “Bestandsschutz”… Make sure you turn off the fuse before handling it (but I guess it’s off anyway when you have the wires hanging around like that). It’s nothing too complicated and if you are a bit handy it’s a piece of cake.

  3. You’d be certainly surprised. There is a sub for this. But the usual advice you’ll get there is “call an electrician”. So, you heard it here first.

  4. > a ground yellow/green

    Yes, yellow/green is protective ground.

    > blue neutral cable is tied to about 4 green/yellow.

    Can happen in older buildings, they don’t separate neutral and protective ground. Not ideal, but you can leave it (“Bestandsschutz”). We are talking major cabling changes if you want to change it.

    > The black live cable seems to be tied to the right black cables

    Then I’d guess that you have a bunch of more lights that belong to the same switch.

    > where to connect the new light.

    If the new light has no protective ground (because it has no metal surface): Attach in exactly the same way as the old light fixture.

  5. Great application of Lüsterklemmen, comes with an automatic voltage detection feature! /s

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