Tim S wrote:
mitchd wrote:


Pause for thought indeed, been an electrician for nighon 30 years and
would not consider earth rod for outbuildings unless their was an
existing tt system, just as likely to loose your earth rod connection as
your main supply earth surly, how often should your earth rod be tested
3mts, 6mths a year? That just will not happen in a domestic house, As
long as rcd protection is used,imo using house earth is the safest way.


Hi

I won't argue with experience (especially as I have little, but just happen
to have read around the issue a bit)...

The only thing I would add is that at least a local rod (or rods) can be
maintained under reasonably controlled conditions and inspected/tested
regularly IMHO.

As to the likelihood of a PME supply failing wrongside - I don't know how
likely that is in reality, but it is outside of the householders control.

Perfectly valid point on (not) testing local TT.

Just out of interest, how far do you consider it reasonable to export a TN-S
earth - I'd be interested for when I have to do it?

Cheers

Tim

Hi don't think distance is relevant, a decent earth loop reading is the
thing i would look for.
and another thing......
if you decided to put in a new pme supply from local electricity
supplier to said garage there would be no need for an earth rod. My
point is all customers really on electricity supplier for an earth point
unless their a tt system.
I have had issues with tn-s supplies, first thing to check is earth loop
had quite a few with high readings, they were simply converted to
tnc-s by local electricity supplier, but the house had been without an
effective earth for who knows how long.