7 Mar 2007
Reaction score
United Kingdom
In my property i have a TNCS earthing, i need to bond my main gas pipe and main water pipe back to my dis board what size earthing do i need to use 10mm??? and can i earth through without cutting the wire e.g from my gas through the earthing strap of the water back to the dis board?
Sponsored Links
Yes 10mm bonding conductor.

Yes connect end at gas, loop conductor WITHOUT CUTTING IT through the earth strap on water pipe to your main earth terminal.

Main earth conductor from incomer to MET should be 16mm to comply with regs. Assuming your meter tails are 25mm.
You can use a single earth so long as there is no breaks in the cable I believe and 10mm is fine if your supply neutral is less than thirty five mm
10mm is probably the right size but you should check with your distribution network operator as they can over rule this.
There is nothing stopping you using the same conductor for both as long as the conductor remains unbroken thoughout its length.
How long is the cable going to be? The resistance of the main protective bonding should not exceed 0.05ohms to from its remote point to the MET.
Sponsored Links
The Earthing Conductor is the one connecting your MET to the source of earthing, in TNCS the DNO's terminal.
Main protective bonding conductors connect extraneous conductive parts such as metallic water and gas services to the MET.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local