Supplementary Bonding question ?

[Soulsurfer]

Hey all, I am trying to ascertain if I need to install supplementary bonding to existing old premises to upgrade while doing 2x CU's and some circuit jiggling ! Am I correct in thinking if reading with R2 wander lead clipped onto MET and me & MFT at say bathroom pipework get reading of sub 1,667 Ohms we're o.k. ? without more pipe to pipe bonding ? I have dual RCD 30mA split load cu AMD 3.

 

[derek]

It would be beneficial for you to get yourself a copy of Guidance Note 8 to gain a better understanding of what the requirements are IMHO

 

[Richard Burns]

Supplementary bonding is only not required in a bathroom if there is all of: main bonding, 30mA RCD protection, Compliant with ADS.
If any of these are missing then supplementary bonding is required.
On an installation the bonding conductors should be accessible for testing and maintenance (they often aren't) so this can be checked to see if it is in place and continuity testing will ensure it is correctly installed..
On a periodic inspection you can, if the connections are inaccessible, test between local circuits, pipework and other extraneous items to see if the resistance between all of these parts is less than 0.05Ω if it is then you can assume supplementary bonding is in place.