I currently live in Spain, in an old building, where apparently electrical codes don't strictly apply... because not all outlets have ground or, indeed, not all connections are grounded. To make matters worse, the colours on the wires used are, well, haphazard, to say the least...

So if I want to install my own grounded outlets to avoid "exploding" my electrical stuff (because there're constant surges that have already fried 2 computer transformers) and in the wall I see mains wires of lovely rainbow colours that don't really tell me which is which, how can I test which wire belongs to neutral and which wire belongs to ground?

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  • Probably not the best answer, but if your building at least has a GFCI/RCD you could test which way around causes that to trip; a resistor between live and neutral won't trip it, but one between live and ground will. – Hearth May 9 at 12:29
  • That's clever but does that assume you know which wire is gnd? I would use the plumbing as a reference voltage . – Sunnyskyguy EE75 May 9 at 12:33
  • Do you know what style of 'ground' your building thinks it uses? This might affect the potential fault scenarios, and possibly narrow down how much the difference matters. Do you have a 2-pole incomer isolator? – Sean Houlihane May 9 at 13:32
  • With a home in an area that has spikes or surges the best method would be to add a whole house surge suppressor at the service panel, by installing at the service panel everything in the home is protected. – Ed Beal May 9 at 13:38
  • 2
    buy a cheap outlet tester, it will tell you what's going on in a foolproof and safe manner. – dandavis May 9 at 19:13

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