Bonding and earthing

[Chrisknowlesuk]

Hi...

I think I know the answer to this question but just wanted to hear what others said..

I'm upgrading a CCU and as part of the job I have done an inspection of the current installation which was a diy job. I don't think the owner was qualified but they have done quite a professional job and 'generally' pay gogod note to regs and safety etc.

However, there is no earthing to gas and water. I queried this with the owner. All water pipes are plastic but they have connected the gas pipe using a 10mm cable to copper heating pipes which are then eventually bonded to the ring main so effectively going back to the CCU via a 1.5mm earth. These connections are inaccessible.

I know this should be a 10mm straight to th CCU and will advise as such but what code would this be. Presumably it is then up to the owner. Would this be put as an advisory note on the certificate.

Also the Ze was super low at 0.06. Its a TT system with the Earth also connected to a lead water pipe in the garden

Any thoughts

 

[Leesparkykent]

No earthing and bonding has to be up to scratch to issue the electrical installation certificate. The lead main cant be used as an electrode as I doubt its part of a private water supply. Water probably needs bonding as its lead incomer....the gas will almost certainly need bonding. If the customer isn't willing to accept this then walk away.

 

[PEG]

Hi bud,just out of interest,what inspections did you do,regarding the earthing,and how was the Ze measured?

 

[Wilko]

TT with Ze of 0.06 Ohms may be a measurement error ?
A typical good rod might give 100 Ohms (say), so this would need 1667 of them in parallel to get that result. Maybe measuring the bonding cable?

 

[westward10]

Have you located the electrode.

 

[The Ghost]

I'm with @Wilko on the reading, you must have picked up a parallel earth. As @westward10 where is the electrode? No bonding code? C2 potentially dangerous.

 

[PEG]

Have you located the electrode.

It's 7000+ miles long,and it touches magma

 

[Rpa07]

You make this sound dirty!

It's 7000+ miles long,and it touches magma

 

[PEG]

You make this sound dirty!

I apologise,if "touching magma",reminded you of an encounter with an Icelandic girlfriend...

...Just waiting for this sun to thaw the snow we had this morning...(not joking,either)

 

[bigspark17]

I highly doubt your true ze is 0.06 ohms

 

[Deleted member 72666]

Also the Ze was super low at 0.06. Its a TT system with the Earth also connected to a lead water pipe in the garden

I suspect the lead pipe is responsible for your low Ze.

 

[sparksburnout]

I don't want to appear critical at all, but how can you be thinking of undertaking a CU change (or CCU as you call it), and leaving inadequate bonding with a "note on the certificate"? It's not "up to the owner" it is up to YOU to do it as per BS7671. How do you imagine a TT system would have a Ze of that value?

 

[Jiibrass]

Have you measure TT with Ze of 0.06 Ohms twice?

 

[Pete999]

Hi...

I think I know the answer to this question but just wanted to hear what others said..

I'm upgrading a CCU and as part of the job I have done an inspection of the current installation which was a diy job. I don't think the owner was qualified but they have done quite a professional job and 'generally' pay gogod note to regs and safety etc.

However, there is no earthing to gas and water. I queried this with the owner. All water pipes are plastic but they have connected the gas pipe using a 10mm cable to copper heating pipes which are then eventually bonded to the ring main so effectively going back to the CCU via a 1.5mm earth. These connections are inaccessible.

I know this should be a 10mm straight to th CCU and will advise as such but what code would this be. Presumably it is then up to the owner. Would this be put as an advisory note on the certificate.

Also the Ze was super low at 0.06. Its a TT system with the Earth also connected to a lead water pipe in the garden

Any thoughts