I've just upgraded a consumer unit for a client. In the process I did all relevant tests on circuits in order to produce a certificate.
The bonding to gas pipes was 10mm but the water bonding was only 6mm. I have informed the client that this needs upgrading to meet regs and even offered to do this at no extra cost (all part of the service)...
In the meantime they have had boiler issues and the engineer that fitted the boiler originally has attended. The client queried what I had said and the boiler engineer that apparently made this connection has told the client that it is sufficient.
If the client is resistant in having this done where do I stand on issuing a certificate? Can I still complete the certificate noting that it is only a 6mm bond? Perhaps add it in the notes?
I haven't asked when the boiler was fitted so perhaps it was compliant at the time?
Confirm the earthing system and if it should be a 10mm then inform the client one last time and mention that it will have to be a departure on your Electrical Installation Certificate as these (departures) do have to be agreed with the client.
The gas is in 10mm and I've always thought that it should always be 10mm.
Done some research and come across adiabatic equations etc suggesting 6mm could be allowed??? But I would have thought for hardly any extra cost then 10mm would have been best practice.
I think most of us have opted to carry the 10mm for bonding these days, and I know many reference documents do recommend 10mm.
But 'if' on this occasion it could be a 6mm, and the Boiler guy is right, then it's best not to dispute. I agree though, especially as the gas is 10mm, I would have replaced it.
It's funny though, I thought the 'earthing and bonding' training boiler people get most often would just say 10mm as well, it's less thinking for them.
Replacing it would mean drilling a visible hole into the house which I would make look respectable but I think the client doesn't want to go for it.
I may suggest that although best practice would Ben to replace it, I could still sign it off and add the relevant notes if that is what he'd rather I do.
The gas is in 10mm and I've always thought that it should always be 10mm.
Done some research and come across adiabatic equations etc suggesting 6mm could be allowed??? But I would have thought for hardly any extra cost then 10mm would have been best practice.
Adiabatic equation is for cpc/ earthing conductor sizes and not protective bonding sizes to which there's not much wiggle room.
Depending if it's a TN-S system the water bond tho not 10mm could be satisfactory being 6mm
For TNC-S, the guidance offered by my scheme technical (NIC/Elecsa) for main protective conductors to water & gas services (when doing alterations, additions or CU change) would be typically a minimum of 10mm (table 54.8). Previous guidance was that if a 6mm was installed and there was no sign of thermal damage, and the client was informed & declined it could be left as is, with note etc. The guidance now is all new work now has to comply, especially earthing & bonding (reg 132.16).
Which is fine and dandy, but the water service is always invariably the must difficult to access. Perhaps we should start a petition to have that service enter the property, with the others!
Of course if the service pipe is plastic, then it would not require bonding, but then reg 528.3.4 should be considered, with fault protection in accordance reg 411.
A picture paints a thousand words - Get your 'on-site' guide out, show the customer the images of earthing arrangements (all show 10mm bonding) - the customer will side with you not the boiler engineer.
Reply to Water bonding only 6mm in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net
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