Another earth bonding question

I've been looking at a pal's installation where the CU really needs updating due to extras having been added over the years. The house is '60s built with imperial wiring in PVC, but earths appear to be present everywhere including lighting circuits. The CU *I think* isn't original as it has MCBs and much appearance of 'bodging' inside - lots of chocolate blocks. The house has been altered quite a bit and the wiring additions look like standard builders work...;-)
However, the main problem I can see is the safety bonding. It's a PME supply, in the built in garage where the CU is also. There's an earth block, but only the gas pipework is bonded - nothing to the water system. And that's the snag. The stopcock is in the kitchen and an extension has been built between it and the garage making concealing an internal earth wire virtually impossible. However, there's a mains water tap in the garage which is fed off the adjacent cloakroom which is all plumbed in copper and there is continuity from that to the pipework in the kitchen after the stopcock. So is it acceptable to bond to that or will it need an earth run all the way round the outside of the house to the kitchen?
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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I'm pretty sure wiring regs say "on the consumer side of the main stopcock" - presumably so that later plumbing changes would be less likely to result in disconnection of the bond. However your proposal sounds better than no bond at all.
Given the number of bodges you describe, a full test as per the OSG might be in order.
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It's a bit of a minefield. My version says 'as near as practicable to the point of entry of that service. But then goes on to mention 're-emerging' pipework and suggests that any which is underground etc should also be bonded where it emerges. Which must include lots of houses with solid floors.

Indeed. My initial idea is to use enough ways to give the radials connected to the rings at the consumer unit their own suitable MCBs, and more or less the same with the other additions, as it's easy to identify the original circuits. Then do a thorough inspection of each one, test and repair or re-do as necessary. The biggest bodge is the garden lighting etc - but at least that is all easily accessible.
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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wrote:

What would you define as practicable? An external 10mm earth cable that goes all the way to the stoptap does not sound unpracticable just bloody awful to look at.
I would want to see the gas and water bonded before any branches in the system. On gas this may often mean an external connection (usually in the meter box).
Re-emerging pipework may have to be bonded and is APITA.
Adam
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Indeed. And in this case would mean crossing two sets of patio doors if the shortest route. The longer one - which would include crossing the front of the house - would probably mean 16mm due to the length. ;-)

In this case it's right beside the CU. And 'they've' bonded that. But not the water. Nor did it ever exist judging by the condition of the screws on the earth block.

Indeed. As I said before I wonder just how many bother in a house with solid floors.
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Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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wrote:

Any chance of an up and down type run?. I have just bonded a house where the CU and gas meter were at opposite corners of the house and I managed to hide the cable behind fall pipes and run it through the loft.

Professionals do not bother. Good DIYers will
Adam
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