[Gllug] OT: Mains electricity colour coding.

[Richard Jones]

On Sun, Oct 24, 2010 at 06:58:44PM +0100, general_email at technicalbloke.com wrote:
> For time immemorial I have been told brown is live, blue is neutral and 
> yellow/green is earth. Mains electricity is AC so it oscillates between 
> the positive and negative 50 times a second right? In that case why does 
> it matter which way you wire the blue and brown cables to the nominally 
> blue and brown terminals in a plug? I always assumed you could 
> electrocute yourself equally well by touching the blue terminal, maybe 
> even better as the brown's got a fuse that might protect you!

As another reply said, neutral is wired to earth, although not as
close to your house as the real earth so it could still be dangerous.
The real earth should be wired to your pipework and to an earth rod
directly under your house (at least, it is in my house ...)

Wikipedia has some interesting articles around this subject:

https://secure.wikimedia.org/wikipedia/en/wiki/Ground_and_neutral
https://secure.wikimedia.org/wikipedia/en/wiki/Ground_%28electricity%29
https://secure.wikimedia.org/wikipedia/en/wiki/Electricity_distribution
https://secure.wikimedia.org/wikipedia/en/wiki/High-voltage_direct_current
https://secure.wikimedia.org/wikipedia/en/wiki/Single_wire_earth_return

Rich.

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Richard Jones
Red Hat
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