On 29/12/2010 15:23, ARWadsworth wrote:

No reg I am afraid. There maybe something in the ESQCR.

It's the ESQCR, Regulation 24 (4):

"Unless he can reasonably conclude that it is inappropriate for reasons
of safety, a distributor shall, when providing a new connection at low
voltage, make available his supply neutral conductor or, if appropriate,
the protective conductor of his network for connection to the protective
conductor of the consumers installation."

[http://www.legislation.gov.uk/uksi/2002/2665/made]

IOW all *new* supply connections shall be PME (or TN-S) unless that
would be unsafe. In practice this means almost all new permanent
premises supplies will be PME (the DNOs tend not to do TN-S any more).
They will refuse to provide an earth terminal for temporary builders'
supplies, supplies to caravans and boats (where PME is explicitly
illegal) and to some types of street furniture.

AFAIK DNOs are not under any obligation to provide TN earthing to
existing older supplies, although they will sometimes do so if you ask.

--
Andy