Earth bonding questions

[MadAlicesDad]

I’m replacing a suspended timber room floor due to rot and have uncovered the copper gas and CH pipes. I cannot recall seeing any supplementary bonding anywhere in the house, and have an opportunity to do so now. Should I link all three (gas/CH feed/CH return) together and is 4mm cable adequate?
The next project will be the kitchen and I suspect the incoming water pipe is not bonded either, especially as it is at the opposite end of the house to the consumer unit and there is a concrete floor in the way. Should the main bonding for this be run back to the consumer unit or is it adequate to install an earth rod under the dining room floor and run a 10mm cable from it to the incoming water pipe?
Finally, if I do install an earth rod, should I link the gas/CH pipes to it as well?
TIA
Mike

PS I’ve also discovered the source of the ‘damp’ smell in the room – a joint in the gas pipe had never been soldered when installed 20+ years ago and was held together by flux only!

 

[mikeyd]

I'm no expert but I think supplementary bonding in a house usually only applies to bathrooms, the experts will advise.
Your main bonding is much more important and the size of the cable depends on your incoming supply type. You can't put an earth rod in, it will need a cable/cables from where your water and gas enter the house to the consumer unit or the earthing terminal next to it.
It will help if you know your supply type. Do you have an earth rod? Is there any stickers on your main fuse saying 'PME'?

 

[flameport]

Should I link all three (gas/CH feed/CH return) together !

No. Complete waste of time. No requirement for this, and there never has been. The gas and water pipes are all linked together at the boiler anyway, and the feed/return pipes are just different parts of the same pipe.

The incoming gas and water pipes should be connected to the main earthing terminal using 10mm wire. Connections to the pipes being where they enter the building.

install an earth rod under the dining room floor and run a 10mm cable from it to the incoming water pipe?

This will do nothing. The metal water pipe is already buried in the ground...
You are not 'earthing' the pipes. You are connecting them together so that they are at the same potential.

 

[Taylortwocities]

[The incoming gas and water pipes should be connected to the main earthing terminal using 10mm wire. Connections to the pipes being where they enter the building.

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Not quite: connection to be witin 600m on the consumers side of the stop cock and before any branch. Or bonding at the point of entry to the building if the meter is external (see 544.1.2)