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Main Bonding issue.

Discuss Main Bonding issue. in the Electrical Forum area at ElectriciansForums.net

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W

wcampbell

Hi all.

I 'm getting 1.58ohms continuity on this main 10mm Earth bonding to water. The bond continues up to the flat upstairs and who ever did the work threw in 12" length of 4mm earth for good measure. Am I missing something or is this a case of new E Bond. Fitted a new clamp but did little to reduce the figures.

Any thoughts please.

Thanks.
 

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tony mc

Electrician's Arms
I think you have answered your own question in that the figure is too high and if it was 10 mm cable you would be looking at a lenth of 863meters.

You have already found a bodge job with the 4mm so IMO put it right by installing a new cable.
 
W

Welchyboy

Even 4mm should give u a better reading than that, replace it!
 

Archy Styrigg

Forum Mentor
Hi all.

I 'm getting 1.58ohms continuity on this main 10mm Earth bonding to water. The bond continues up to the flat upstairs and who ever did the work threw in 12" length of 4mm earth for good measure. Am I missing something or is this a case of new E Bond. Fitted a new clamp but did little to reduce the figures.

Any thoughts please.

Thanks.
What a mess, hope that's the before picture!
Put in new separate 10mil bonds from where the water enters each flat to the respective METs.
Scrub the pipes to shinyness before fitting the clamp then test from the pipe to MET, what I was taught.
And use ring crimps.
 
E

Engineer54

Hi all.

I 'm getting 1.58ohms continuity on this main 10mm Earth bonding to water. The bond continues up to the flat upstairs and who ever did the work threw in 12" length of 4mm earth for good measure. Am I missing something or is this a case of new E Bond. Fitted a new clamp but did little to reduce the figures.

Any thoughts please.

Thanks.
Disconnect this cable to the upstairs flat, it should not be leaving your equipotential zone or be influenced/connected to/by another equipotential zone. As others have suggested, if required replace the bonding conductor back to the MET.

Just to be certain, why not check this water service, to see if it is an extraneous earth!!! might just be a section in plastic somewhere...lol!!!
 

Mfctitch

Regular EF Member
Disconnect this cable to the upstairs flat, it should not be leaving your equipotential zone or be influenced/connected to/by another equipotential zone. As others have suggested, if required replace the bonding conductor back to the MET.

Just to be certain, why not check this water service, to see if it is an extraneous earth!!! might just be a section in plastic somewhere...lol!!!

Not sure if this comment helps but looking at the photo, it looks like the mains water supply is plastic.
 
W

wcampbell

Thanks all.

The pipe work is all metal apart from main incomer. Will replace main bond this coming week.
 
E

Engineer54

Thanks all.

The pipe work is all metal apart from main incomer. Will replace main bond this coming week.
Then you need to do an IR test from the MET to the metal side of the water service pipe. If it's under 23000 Ohms (23 KOhms) it requires bonding, if over, then it's not an extraneous earth, and no bonding is required. But you'll still need to isolate/remove that bonding cable that is going to, or coming from the flat above....
 
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