On Thu, 17 Feb 2005 23:31:18 +0000, Ian Stirling wrote:

Andrew Chesters wrote:
Ian Stirling wrote:
Christian McArdle wrote:

I'm sure I should know - but what is PME ?

It stands for Protective Multiple Earth and is an obsolete term for
describing what is now known as TN-C-S. These letters, which are based on
French indicate that:

T - earth is related to ground potential. (alternative being I- isolated)


Silly question - is this 'ground', as in the big ball of stuff we're all
sitting on?
More or less. UK = Earth, USA = Ground, don't know what the frog-eaters
et. al. call it!! :-) It should be at zero potential in relation to all
live conductors, and is normally? bonded to neutral at the generator and
sub-stations.

Ok.
I thought this was the case, but was wondering if there was some strange
non-obvious definition.
...
Idly wonders what the resistance from the UK to USA is.

Apparently very much less than proportionate to the
resistance from your house to the substation. The distance is huge but so
is the cross-sectional area. AIUI the bulk of the resistance to ground is
near the earth rods where pathways for the current are bunched together.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html