I need to replace a dual electrical outlet and fix some melted insulation/exposed wires inside. I found that the two sockets are wired like this:

enter image description here

Coming out of the wall I have dedicated wiring for each socket, but for some reason the sockets are also connected to each other (ground to ground, etc). Why the "extra" wiring? Should I keep it?

Edit: these are Type F outlets in Germany.

  • 2
    Where on the planet is this wiring?
    – Ecnerwal
    Commented Aug 24, 2020 at 14:52
  • @Ecnerwal Germany, these are Type F plugs with 2 earth clips (standard across the EU + Eastern Europe I think).
    – kontextify
    Commented Aug 24, 2020 at 14:58
  • 1
    I would be worried more about why the insulation is showing signs of extreme overheating. MIght have happened once in the dim past, or you may be overloading the circuit just short of tripping breakers (assuming the breakers are properly sized for the wire gauge in use) Commented Aug 25, 2020 at 15:34
  • 1
    Moisture causes a high resistance corroded connection which heats up and anneals the conductor and the heat transmits along the wire and burns the insulation relative to the distance from the connection. Wires would need to be cropped or replaced and new wires would need to be assembled in a no unlocks meaning a anti-oxide paste. I am an Electrical Contractor in silicon valley Commented Aug 25, 2020 at 15:45

1 Answer 1


Very likely the actual path is: Out of the wall, into one socket, on to the next socket, and then back into the wall to some other socket or other load on the same circuit.

Have you identified the circuit breaker which feeds these (which would be a good sign) or breakers (something would be wrong if you need to turn off two breakers to turn these two off.) See what else is on the circuit that shuts off when you shut these off.

  • 1
    D'oh! Yes, that's what's happening.
    – kontextify
    Commented Aug 24, 2020 at 16:15
  • Possibly as it's a ring main
    – abligh
    Commented Aug 24, 2020 at 21:22
  • 1
    @abligh doubtful, ring mains are a UK only thing and the OP is in Germany. Commented Aug 24, 2020 at 23:13
  • @DanIsFiddlingByFirelight interesting - thanks! I assumed they were also present elsewhere in Europe too.
    – abligh
    Commented Aug 25, 2020 at 2:12
  • @abligh nope. They were a post WW2 austerity measure in the UK. The rest of the world thinks the enormous plugs/outlets needed to make them safe are an unreasonable trade off to save a little bit of wire. Commented Aug 25, 2020 at 2:44

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