Can anyone mail me the various earthing methods?

Question

For example TT TT-s, a printable version would be a god send i am no where near my 16th edition book

Answer 1

OK here we go.
TT = Terra/Terra which is derived from the French for Earth/Earth
The star point at the sub station has an earth rod and the premises utilising the supply has an earth rod . Hence Terra /Terra
A rcd device is normally fitted to this type of supply of around 500 mA or less.
TNS = Terra / Neutral Seperate which means that the supply is normally a paper and oil insulated cable into the premises with the outer sheath providing the earth point to the installation. Phase and neutral are seperate cores inside the cable.
TN-C-S Terra/ Neutral combined then Seperated.
This is normally a concentric cable with a single inner core which would be the Phase conductor.
The outer armouring is combined Neutral and Earth.
This is seperated at the point of connection in the premises with an earth bar on the side of the service head to the earth connection point , hence Combined then Seperated.( PME SUPPLY )
Hope this clarifies the points raised.

Answer 2

TT Earth stake with RCD for leakage protection
TNS Supply company provides a dedicated earth connection from the supply cable sheath
TNCS Supply company allow use of thier neutral connection (provided all other services and external metal works are correctly bonded)

There are others but would not normally be used in domestic or small comercial installations.

Answer 3

Your best bet is to get a copy of the IEE Site Guide. This should be available from a decent bookshop or you can buy it on line.

Answer 4

T = tera (french for earth/ground)
N = neutrual
S = seperate
C = combined
TN-S = EARTHED TO ARMOUR OR METALIC SHEATH.
TN-C-S =PME EARTH.
TT = EARTH RETURN VIA EARTH ELECTRODE.