Exporting the earth?

[Deleted member 9648]

Why do you disagree?

Antimatter I disagree because you are incorrect.
If you check bs 7671 you will find no restriction or even mention of TNCS supplies and outbuildings other than in special locations,it is bs 7671 that we work to.
The DNO are only interested in the installation comlying with bs 7671.
Some may prefer to separate and TT, that is their choice.
But PLEASE get your facts right before posting that exporting TNCS is not permitted...IT IS.

Thanks to IQElectrical for sticking with this one....you displayed a lot more patience than I would of if I'd been around.

 

[antimatter]

Antimatter I disagree because you are incorrect.
If you check bs 7671 you will find no restriction or even mention of TNCS supplies and outbuildings other than in special locations,it is bs 7671 that we work to.
The DNO are only interested in the installation comlying with bs 7671.
Some may prefer to separate and TT, that is their choice.
But PLEASE get your facts right before posting that exporting TNCS is not permitted...IT IS.

Thanks to IQElectrical for sticking with this one....you displayed a lot more patience than I would of if I'd been around.

Not if there is any extraneous metalwork in the outbuilding.

 

[telectrix]

as long as the extraneous metal is bonded back to the MET. suitable bonding installed.

 

[Engineer54]

Not if there is any extraneous metalwork in the outbuilding.

What's the difference, whether there is extraneous metalwork at/in the outbuilding or not?? If there is, you bond any extraneous metalwork back to MET, same as you would at any other type of building, all you are basically doing is ''extending the installations equal-potential area. You've been listening to too many scaremongers, that have a dislike of PME supply systems.

 

[antimatter]

Because if there is an earth fault on the outbuilding, and both the outbuilding and main building are linked together by means of earhing, the fault on the outbuilding is then present in both buildings, that's why we separate and TT the outbuilding so the fault is sent through the earth electrode and to the general mass of earth.

 

[Dave_]

Because if there is an earth fault on the outbuilding, and both the outbuilding and main building are linked together by means of earhing, the fault on the outbuilding is then present in both buildings, that's why we separate and TT the outbuilding so the fault is sent through the earth electrode and to the general mass of earth.

Not necessarily. TT may be the preferred method for this reason but you have option of the two, to stick with TNC-S or seperate and TT the outbuilding.

 

[Engineer54]

I don't think you read my last post..... ''bond any extraneous metalwork back to MET, same as you would at any other type of building, all you are basically doing is ''extending the installations equal-potential area.''

There would be exactly the same fault conditions no matter what type of supply is installed, and there are certainly no restrictions on extending a TN-S system!!!!

 

[antimatter]

Not necessarily. TT may be the preferred method for this reason but you have option of the two, to stick with TNC-S or seperate and TT the outbuilding.

There is no option because of the earth potential introduced if there is extraneous parts in the outbuilding, therefore not complying with the regs.

 

[antimatter]

I don't think you read my last post..... ''bond any extraneous metalwork back to MET, same as you would at any other type of building, all you are basically doing is ''extending the installations equal-potential area.''

There would be exactly the same fault conditions no matter what type of supply is installed, and there are certainly no restrictions on extending a TN-S system!!!!

Thats because the earth system is what it says in the name S - separate earth. As oppsosed to a combined Neutral and Earth conductor.

 

[Dave_]

Thats because the earth system is what it says in the name S - separate earth. As oppsosed to a combined Neutral and Earth conductor.

Thats TNC!!!

TNC-S Terra Neutral Combined (DNO!!!) Seperate (Consumer!!!)

 

[Dave_]

And yes TNC is banned!!!

 

[antimatter]

Thats TNC!!!

TNC-S Terra Neutral Combined (DNO!!!) Seperate (Consumer!!!)

Yes we all know what TNC-S stands for Dave well done for that, i was pointing out to engineer 54 that there are differnt rules on TNC-S and TN-S thats all, there is no need for you to explain very simple acronyms to us all thank you.

 

[Engineer54]

Thats because the earth system is what it says in the name S - separate earth. As oppsosed to a combined Neutral and Earth conductor.

Do you actually understand the fundamentals of ''equal-potential bonding'' ??

 

[antimatter]

Do you actually understand the fundamentals of ''equal-potential bonding'' ??

And do you understand its Equi-potential not 'equal-potential!!!

 

[Guest123]

Antimatter,

With the greatest of respect, you are 100% incorrect in this instance. Please examine the afforementioned literature and also contact your local DNO for further assurance if needs be.

There are probably hundreds of seperate threads on these forums regarding the exporting of a suppliers TN-C-S system and all conclude with the same answer which is, it's absolutely fine to do so providing any exposed steelwork/pipework that may be present in that building is connected to the installation M.E.T/B.E.M.T via a suitably sized main protective bonding conductor.

To continue in your current vane is non productive and misleading to others.

Regards.