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Does Neutral really equal Earth??

Discussion in 'Electrics Outside of the UK' started by Multiplex, 25 Apr 2006.

  1. Multiplex

    Multiplex

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    I'm renovating a flat in Germany (built in 1958) and I was disappointed to find that the entire electrics have been wired with two wires, and no earth wire.

    At the sockets they have put a small wire loop connecting the neutral terminal to the earth terminal.

    My question is, is this safe and what are the pitfalls? My understanding is that the neutral wire on new houses is connected to the main earth provided by the electricity company. In this case, what's the real difference?

    I have a more important problem which I'd like an answer to. There's an "earth" wire in the bathroom which I should really connect the shower tray to (give the water heater for the shower is 21kw @ 400v!!), but in the event that this "earth" is actually a "neutral" wire...should I still connect it?

    And...I do realise that the flat needs a total rewire, but I just can't stand living in Germany any longer...

    Thanks,
    Simon.
     
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  3. Spark123

    Spark123

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    Only speaking generally as I don't know the 1st thing about German wiring regs, it sounds like a tn-c type system which goes to tn-cs as each socket outlet??, rather like what the DNO here do for our tn-cs systems at their knockout. (Here a consumer is prohibited from doing what you say by the ESQCR.) Some problems I can think of is a broken neutral causing the appliance to become live at a different potential to the rest of the premises, and the risk occurence of a broken neutral being increased by the nature of the installation. In theory neutral should be close to 0v and terra connected at the supply transformer (in the UK anyway). Current flowing through the resistance of the neutral conductor can cause it to be a few volts above true earth, (depending on the vector sum of the 3phase neutral currents and PME). So instead of the whole installation being equipotentially bonded to earth give or take a few volts as in the UK, there is also the resistance of the circuit conductors to take into account on these type of circuits in Germany as current flowing in the neutral conductor of each circuit will inevitably cause numerous different potentials to be present on different exposed conductive parts??
    A bit of food for thought anyway!!!
    I think the whole of Europe should drop their systems and go for the wonderful Great British way for a change :LOL:
     
  4. Adam_151

    Adam_151

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    East germany?

    Heard it was pretty much common practice to do that there when converting an ungrounded outlet to a grounded one, not sure whether it was actually allowed or not, but its the way I'm lead to believe it was often done
     
  5. RF Lighting

    RF Lighting

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    Bring back Red Yellow and Blue!! :D
     
  6. Stoday

    Stoday

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    The method was used (rarely) in the UK in the 1960's for a PME installation.

    Neutral and cpc were common and earthed at multiple points in the installation, to water etc. which were bonded.

    (the regs that prevailed at that time - 13th I think - did not require bonding except for these types of pme installation.)
     
  7. Multiplex

    Multiplex

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    So nothing too much to worry about then? This flat is indeed in East Germany so I guess that explains some of it.

    Do you think the wire in the bathroom was once connected to a water pipe, as opposed to a shower tray? In this case would it be foolish to connect it to the new shower tray which we're in the process of fitting?

    Simon.
     
  8. plugwash

    plugwash

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    Afaict in a hosue with TN-C wiring like that good supplementry bondingis VITAL!

    don't just bond one thing to the neutral wire though without bonding everything in the room or you could make the installation a lot less safe

    and has been said you probablly wan't to contact a local expert to find out the rules on working with such installations. Since they are banned in the uk now and very rare in existing installations its difficult to advise.
     
  9. DIYnot Local

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