On 7 Aug, 20:52, cynic wrote:
On 7 Aug, 13:10, jkn wrote:



Hello all
* * I have a TT earth system supplying mains power to my Garage. The
earth (6mm cable IIRC) *runs from the garage CU to an earth rod
situated nearby.

Whilst at TLC recently I picked up an 'earth rod terminal cover' in an
attempt to tidy up the clamping arrangement to the earth rod:

http://www.tlc-direct.co.uk/Products/MTETC.html

However this unit turns out to be not quite what I expected and I'm a
little unclear how it's supposed to be used.

The earth rod clearly goes in the bottom tube (which swivels), and
then there is just a 20mm or so hole in the side of the box. Is this
intended to take a cable gland for the earth cable? Or just a grommet
of the appropriate size? And why the swivel? I'd have thought this
would encourage small children to play with it and maybe loosen the
internal clamp arrangement.

Thanks for your thoughts

* * J^n

The entry shown on the right is a conduit connector which you would
use to fit a length of conduit into and bring the green/yellow earth
wire through from the clamp to safely end up above the surface of the
ground on the run up the wall to the MET position. The rod would be
driven into the ground through the bottom of the box. Ideally the
insulated box will be flush with the ground surface to minimise
surface potential gradients in the event of fault current passing
through the earth conductor into the ground. This particular box looks
a bit on the small (shallow) side but its better than nothing I
suppose.
I suggest you get your hands on a copy of the CITB book on BS7671 2008
in which technical data sheet 5B/4 is very explanatory. Your local
reference library may be able to help if you dont want to buy the
book. (ISBN 978-1-85751-278-6)

Can I suggest you

Based on your comment about this particular box being rather too
shallow in your experience, can you suggest a supplier of one that you
would use. I'm about to fit an earth rod in a similar situation to
the OP.

Thanks
Rob