Consumer unit upgrade

[Jeremy Hale]

Job is to upgrade consumer unit with RCBO's unit, upgrade tails to 25mm tails, 16 mm main earth, 10mm to Gas, however cant get to water pipe / water stop existing bonding is 4 or 6mm all concealed behind tilled wall, system. any advice

 

[mattg4321]

What is the earthing system.

Are the incoming supply pipes plastic or metallic?

 

[Dustydazzler]

If you can prove that the water pipe is not extraneous then all gravy

 

[timhoward]

I had a similar case recently.
I managed to cut out a tile with a disk without hitting the water pipe and then had enough room to use old conductor to pull through a new one. It was a happy day - I even got the tile back without breaking it!

If that isn't possible, and it is extraneous, I'd prefer to be running a new 10mm to wherever I can get to (literally interpreting "as near as practicable to the point of entry") bearing in mind someone else might need to find it one day.

I recognise that if not PME you could go on a paper trail to see if you can justify the current bonding csa. While not wrong I don't think I'd do that myself as I don't really want to be downsizing a main earthing conductor to solve a bonding problem.

 

[pc1966]

If you can check with a wander lead that the stop-cock is well-connected (e.g. bond resistance 0.05 ohms or so) then it comes down to if it is TN-C-S and merits 10mm instead of the 4/6mm.

I presume the water pipe entry / stop-cock is accessible?