eicr

[1983]

Basically in side the flat a submain ccu in 16mm twin and earth. so main earth at flat ccu is 6mm the flats water and gas is bonded in 10mm and goes straight to the intake in communal cabinet each flat has a 60 amp isolator bout 5flats dp by the way which has obviously the meter tails going in 25mm with 16mm earth from there the 16mm twin and earth goes to flat I need to upgrade the main earth in the flats ccu my boss has said to take a 10mm from the flats gas or water to the ccu met to make it 16 mm main earth. hope it gives u a better picture now lol

Without seeing exactly what you are talking about its hard to know.

Is you boss talking about running a bond from an existing earth marshalling bar, rather than running back to the MET? Or is it that he means to somehow join onto an existing main bond?

 

[davesparks]

Basically in side the flat a submain ccu in 16mm twin and earth. so main earth at flat ccu is 6mm the flats water and gas is bonded in 10mm and goes straight to the intake in communal cabinet each flat has a 60 amp isolator bout 5flats dp by the way which has obviously the meter tails going in 25mm with 16mm earth from there the 16mm twin and earth goes to flat I need to upgrade the main earth in the flats ccu my boss has said to take a 10mm from the flats gas or water to the ccu met to make it 16 mm main earth. hope it gives u a better picture now lol

So the services are already bonded in the flat?
I'm getting completely lost in this thread now. Just to get this clear in my head, why does the earth to the CU in the flat need bonding?

 

[1983]

The services are not bonded from flats ccu met . The flats cc u main earth is 6mm I want to upgrade this earth via running another 10mm earth my boss has asked to take it from the service bond as it's easy route

So the services are already bonded in the flat?
I'm getting completely lost in this thread now. Just to get this clear in my head, why does the earth to the CU in the flat need bonding?

 

[rattlehead85]

The services are not bonded from flats ccu met . The flats cc u main earth is 6mm I want to upgrade this earth via running another 10mm earth my boss has asked to take it from the service bond as it's easy route

So am i correct in saying he wants you to run from the ccu to the service gas /water within the flat in 10mm2 and then use the existing bond connected to the services back to the m.e.t at the intake as a combined earth and bond conductor???

 

[davesparks]

The services are not bonded from flats ccu met . The flats cc u main earth is 6mm I want to upgrade this earth via running another 10mm earth my boss has asked to take it from the service bond as it's easy route

Where are the services bonded? Are they bonded at point of entry to the flat with the bonds run from the location of the switchfuse which feeds the flat? If so then it sounds like it is compliant as it os for bonding. So the earth to the flat's CU would then only need to be a cpc.

 

[rattlehead85]

Where are the services bonded? Are they bonded at point of entry to the flat with the bonds run from the location of the switchfuse which feeds the flat? If so then it sounds like it is compliant as it os for bonding. So the earth to the flat's CU would then only need to be a cpc.

From my experience this sounds like a street property split into flats with a communal intake with the gas meters and water stopcocks located near to the intake. They are most probably link bonded back to the M.E.T. within the intake.

 

[1983]

Yes they are bonded at the point of entry to the flat and go to the intake met

Where are the services bonded? Are they bonded at point of entry to the flat with the bonds run from the location of the switchfuse which feeds the flat? If so then it sounds like it is compliant as it os for bonding. So the earth to the flat's CU would then only need to be a cpc.

 

[Deleted member 26818]

How can you apply the adiabatic equation to size an earthing conductor on a tn-c-s when it is supposed to be sized in accordance with the sizing of the main protective bonding. The adiabatic equation is used on tn-s & t.t installations and normally is used to confirm adequacy of existing earthing conductors on said existing installations. For new work the relevant tables in BS7671 for sizing of protective conductors in tn-s / t.t installations should be used.

The adiabatic equation is used to ascertain whether the earthing arrangements are adequate.
Please note that the requirement for a minimum CSA of 10mm is for where PME conditions apply.
PME is not exclusive to TN-C-S.