You would expect to see the star point of the LV winding brought and distributed as the neutral and also connected to an earth electrode. That is the 1st T in TT the second T is the consumers earth electrode.

Hope this helps?

JP

Not sure what you mean by 'body earthing' here.  In a normal TT system the neutral is earthed at the substation, and the core of the transformer may share that LV earht or may have its own 'HV earth' - mainly that decision comes down to the likely voltage rise during fault.

Mike.

If however you mean earthing the neutral at another transformer fed by the substation, that is some TNC varient. I suspect not what you meant.

I mean neutral and transformer outer cover (conducting material) earthing 

OK- on a site where a low earth impedance is not easy (electrode impedance to terra-firma >1 ohm, say) then during a fault from transformer primary to core or case (- you call this the 'body' I think) then the transformer and it's metalwork rise to a dangerous potential. In that case that is earthed to a separated ' HV earth' or 'Primary earth' while the LV side neutral then has its own electrodes, some metres outside the near field of the HV earth.
If however the earth electrode impedance is very good (say less than one ohm) and/or the HV supply impedance is very high, so this rise of voltage during a primary fault would be small (only a few hundred volts), then the HV and and LV sides may share one set of linked electrodes.

To confuse matters a bit, sometimes in UK supplier slang the single shared low resistance earth sites are referred to as having 'cold' earths and those with the risk of a dangerous voltage rise are called 'hot' earths or are ' hot sites' .

In the UK most agricultural/ village wooden pole mounted transformers are 'hot' and so the HV primary earth wire comes down the pole with the transformer on it, while the LV/ neutral earth comes down the side next pole along the line 10-20m away.

Very large substations at ground level in towns and cities have far more metal in the ground, and are more often than not 'cold'. But even so, not always - sandy soil and high potential for fault currents require electrode separation in some places.

Hope this helps a bit.

Mike

Also be aware that in some parts of the world, N is distributed on the HV/primary side - in the UK we tend to assume that any talk of N will mean the LV/secondary side, but that's not necessarily always the case.

I think normal UK practice is to Earth the transformer case on the HV/primary side (which may be solid metal back to the HV source, or a local electrode, depending mainly on whether the cables are overhead or underground) - LV N is always connected to Earth - sometimes sharing the same earthing facility as HV or sometimes a deliberately separated earth. Pros and cons to both arrangements.

   - Andy.