tt supply, earth size query

[graham123]

What size earth is acceptable for tt supply to the rod. Supply is 25mm tails from meter to Cu. 6mm earth has been installed to existing rod. Is this too small. Getting 13.1 Ze so passes by a long way. Personally i would like to see bigger earth.

Also MET has a 6mm maked up with Water bond. But when going to look at the stop cock i cannot see an earth bond their because i cannot remove the back panel from under the sink. Any suggestions on a code for this?

 

[malcolmsanford]

The minimum size for an earth conductor on a TT system is 2,5mm if you mechanically protect it, or 4mm if not protected. For good practice you could check it by Adiabatic equation, but 6mm is ample I would imagine.

Yes code 3 on the new EICR as long as you proved continuity, If there is continuity then reg 526.3

If you can not proved continuity then I would code it a definite 2 and perhaps even a 1, depending though on your risk assessment

 

[Deleted member 26818]

Agree with Malcolm onthe CSA query, however I would consider a code C2 with a tick for further investigation required for the inaccessible earth connection.