equipotential bondin

[sijaysee]

hi
i cant find any earth clamps connected to the 2 stop cocks in the property. i did a continuity test and am getting around 0.04 ohms reading.

does it matter that i cant locate the claps and that i can take it as read that the pipes in question are bonded?

also need to extend the ring main and cooker cables by about 1m to put them into a new CU. wot is the best way to join them?
Im thinking crimps

 

[GaryMo]

You need to locate the connections for the Main Protective Bonding Conductors, disconnect each one and verify end to end resistance is 0.05 ohms or less.
The BS951 clamp and 'Safety Electrical Connection - Do Not Remove' label should be available for inspection.

Crimps are one way to extend a cable, assuming they've been properly terminated.
Would the connections you need to make be available for inspection? If so then junction boxes or an adaptable box with dinrail and terminals may be other ideas.

 

[sijaysee]

i've searched for clamps but to no avail. used a long lead and probes directly to the pipework and got those low readings.

what im asking is do i have to put new clamps on or is it ok as it is bearing in mind that there definately is continuity.

 

[Spark123]

Cover your backside, put new clamps on.

 

[RF Lighting]

The reading you are getting may well be a parallel path through the pipes.

BS7671 states the clamps must be within 600mm of the point of entry of the service, and before any branch in the pipework. If you can't find the claamps, then you can't ensure the regs have been complied with.

 

[ebee]

RF is right, you gotta know by proving it otherwise it could be by a method that could lead to accidental disconnection.

Case in point,
I came against one where the kitchen units had been fitted over a visually "apparently OK bond of water on incomming" I viewd it via a mirror, all the evidence (meter readings etc) suggested it was OK, but I could not reach the clamp to disconnect and test properly or even to verify tightness so I flagged it up as such.
It may well have been OK but I could not verify correctly.
The customer (letting Agency) could not sanction my removing the unit or creating an access hole.

 

[sijaysee]

yea i see what you are saying
i will have another hunt tomorrow.
one thought that i have had is that the clamps may be in the next door property as it is a main house with 2 flats with the meters in the house.
what if i disconnect the earths one by one at the MET and test?
If the readings of the pipework at the stopcocks increase dramatically
then that would indicate a clamp somewhere.

 

[ebee]

Nope sorry.
The only way is to (power down) disconnect both ends, check continuity between both ends.
Plus, unless you can visually inspect the entire run which is usually unlikely, to test one end to the pipework for no continuity (on ins Res setting) to ensure the pipework itself is not forming a portion of the bonding conductor.