another bonding Q, what would you do?

brman · Mar 25, 2012

Ok. I know there are lots of bonding questions and I am not about to start another discussion on whether you need to upgrade it to change a light switch but consider this scenario....

Adding a fused (RCD) spur to to a ring to supply the garden. Properly has bonding to gas but not to water (evident by only one bonding conductor into the CU). The catch is that the owner doesn't know where the water stopcock is - he even called in a plumber who could not find it - but he suspects it might be behind some (nicely tiled over) panelling in either the cloakroom, utility room or kitchen.

Would you....
a) insist on pulling the house apart to find the incoming and bond there.
b) bond to the nearest available cold water pipe because it is the best you can find.
c) don't worry guv, I'll pretend I didn't spot it was missing......
?

Knobhead · Mar 25, 2012

Use option B.

Have a read of this http://www.electriciansforums.net/e...al-regulations/46129-just-start-argument.html I have proved the regulations aren’t always right. Copper pipe has a higher conductivity until some cheapskate puts plastic in.

All you can do I make the installation as safe as possible. You could install a new CU all bonding correct at the time of installation. What of the future?

You need a holistic helmet to know what’s behind a wall or what may happen in the future. (I’ll rent my helmet out at £1000 per hour).

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GLENNSPARK · Mar 25, 2012

all i am saying here though Tony....is that inspection precedes testing.....if you cant inspect for any valid reason...then go to testing....after all inspection proves the things you can see......testing proves the things you cant......

Knobhead · Mar 25, 2012

Glen, I know what you on about.

There’s a lot to be said for the old method of cross bonding. Better still ban plastic pipe and train plumbers to solder copper pipe. Plumbing is like putting Skittle Sticks together now.

(Showing my age with Skittle Sticks, I was about 10/12 when they first came out).

GLENNSPARK · Mar 25, 2012

No probs Tony.

brman · Mar 28, 2012

thought I might as well report back as I have just checked this house again. Gas bond goes to gas only. No other bonding back to the CU.
However a check of the cold water pipe at the nearest point to the CU gives 0.04 ohm. (but with the gas bond in place though)

I didn't have time to remove the gas bond and test properly but there is a visible cross bond between the hot and cold water under a sink so I am pretty sure it is being bonded from the gas, through the boiler to the hot water then to the cold water via this bond.

I will be suggesting a new bond to the cold water at the nearest point which just happens to be about 6 feet from the CU and very easy to get to so there is little reason not to.