Earthing systems

[Cj24]

Hi can someone help and help explain the earthing systems for example TNC-S is terre neutral combined separate, but does this mean the earth and neutral come into your property combined then separate etc and what about tt which I know is via a earth rod but tns and tnc sustems

 

[Thomas123]

your right about tncs and tt, tns is seperate all the way through (sheath as earth) and tnc is combined neutral and earth all the way through, very uncommon and you will probably never see it.

 

[trev]

TN-C-S= The earth (supplied by the distributor)and neutral are combined up to the origin of your installation
TT= A distributor's earth facility is not supplied hence the need for an earth rod
TN-S=There is an earth supplied by the distributor which is seperate from the line and neutral often using the armoured sheath of the supply cable
Obviously these are very brief descriptions

 

[i=p/u]

you got osg first few pages have great diagrams then try drawing them to get it too stick.. tncs is combined from the cutout back down your street, in the cunsimmers side it is always separate

 

[i=p/u]

aka no pme

 

[Doomed]

Look in your BRB (or BGB) figs 2.2 to 2.6

 

[Cj24]

Thank u

 

[GLENNSPARK]

your right about tncs and tt, tns is seperate all the way through (sheath as earth) and tnc is combined neutral and earth all the way through, very uncommon and you will probably never see it.

Very uncommon because its not used in this country mate...........

 

[i=p/u]

well technicaly it is used , just not on the consummer side... come on guys get with the big green book

 

[Sparky Ninja]

These may be helpful.

 

[GLENNSPARK]

PME= protective multiple earthing: PEN conductor generally rodded/taped to earth at regular intervals along its length.
PNB=protective neutral bonding: PEN conductor as with PME but not rodded/ taped to earth along its length but relies on the star point being earthed. Generally used to supply a single installation.

 

[i=p/u]

your getting good at this glenspark, quicker than me... i dont like it

 

[GLENNSPARK]

your getting good at this glenspark, quicker than me... i dont like it

Yep my typing skills have come on in leaps and bounds:wacko:

 

[i=p/u]

not just your typing, your knowledge and understanding of the regs.... not bad for a midgit

 

[Rockingit]

Part of the problem of understanding these systems is that quite often the DNO's use different terminology to us.

For example, they commonly refer to TN-C-S as PME. But they also have PNB, SME....

In fact, it would probably be a very useful sticky to have this all as list by others on here with DNO experience to act as translators (not me!).