Main Bonding of an old water pipe.

[nashton]

Im working on an instalation where the main water comes in to the proprerty then goes into a concreate floor and comes up in another room to feed a toilet.

1)
Would the pipe coming up in the toilet need bonding?

2)
Also there is talk of cutting off the current water supply to the toilet and re feeding in a new section of pipe run in a conventional way through the celing cavity. The old pipe will still be exposed in the toilet and will remain in the concreate floor. Would the old section of pipe need bonding? (im thinking along the line of it being similar to structural steel

Many thanks

 

[Engineer54]

You would bond this water pipe wherever it first presents itself within the property... Once only!!

 

[SYKRAPS]

Within 600mm of the (stoptap or where it enters the property) and only once per water supply, you need to make sure it is installed correctly and to regs when you sign it off and should not take into consideration what 'may' be done because as we all know it 'may not' be done.

 

[lewlec]

Hi
seem to remember something in the nic snags and solutions earthing booklet that you need to bond re emerging pipe work... Will see if i can digg it out.

Regards
gary

 

[lewlec]

Found the book...... And the dust.....
ye snag 17 of the book, the book quotes such pipework may, after the intake position, go underground, become 'earthy' and re-emerge in an another location in the premises
there may be doubt concerning the reliability of the electrical continuity of such underground pipe work. Where pipework re- emerges in almost all cases it will meet the definition of an extraneous conductive part and must therefore be permanently and reliably connected to the met in accordance with reg 413 02 02.

Hope this is of use to you
regards
gary

 

[kingeri]

Or you could just test for continuity between the emerging pipework and MET......

 

[lewlec]

Or you could just test for continuity between the emerging pipework and MET......

Ye good idea if so it needs to be under 0.05 ohms

 

[kingeri]

I didn't think it was a good idea! Just fairly obvious!

 

[rich.250]

Ye good idea if so it needs to be under 0.05 ohms

And if over 23k ohms it doesn't require bonding!

 

[lewlec]

And if over 23k ohms it doesn't require bonding!

Yep......

 

[nashton]

Thanks fellas. Where does the 23k omhs come from-i cant find reference to that number. So if there is any extraneous conductive part, such as an old water pipe, that has a resistance of between 0.05 ohms and 23k ohms back to the MET it needs bonding? Clearly main water would still need doing.

 

[rich.250]

Any service over 23kohms will not require bonding as it is not considered a parallel path to earth.
GN8 has a lot more info on this.
If you do bond it you are effectively making it live in fault conditions for no reason.