Mike Harrison 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.

..and of course think about what happens to the earth rod impedance when
we get a long hot spell & the ground dries out...

Yes indeed - I did say it was a minefield...

I've heard differing opinions from engineers too, each with a perfectly goog
sounding argument to back his theory up. I think this is one of those areas
where getting expert advice in a specific situation is most definitely a
good idea, even if it costs... Then I did say I wasn't an engineer.

If it were me, and I'd concluded I ought to TT each out-building,

I'd probably sink two of the longest rods I could physically
bash into the ground (at least 4 feet, preferably more) at diagonally
opposite corners of the building and bond the lot solid.

Then that's just me - "if in doubt, double it, if still not sure double it
again!"

Cheers

Tim