Ah - is this to do with a difference between a 'main' and a 'service'? If so, can you possibly educate me?Tut, tut John Read what I wrote
we cannot do this in a service unless we convert it.CNE cable in an SNE main
Kind Regards, John
Ah - is this to do with a difference between a 'main' and a 'service'? If so, can you possibly educate me?Tut, tut John Read what I wrote
we cannot do this in a service unless we convert it.CNE cable in an SNE main
is this to do with a difference between a 'main' and a 'service'?
In that case there's no such thing as TN-S.Other definitions (I think including BS7671- I don't have my copy to hand) take TN-C-S literally - i.e. if the N and E are combined at some point and then split (anywhere), it's regarded as TN-C-S.
Thanks. In that case, allow me to repeat my question, translated into that language:A main is the cable that generally runs along a street from a substation to which multiple customers are connected. A service is a cable from a main to an individual customer.is this to do with a difference between a 'main' and a 'service'?
Fair enough. Is it common to have a CNE segment, other than very close to the transformer, in a TN-S main?
Is it common to have a CNE segment, other than very close to the transformer, in a TN-S main?
I'm not sure that PNB would qualify as TN-anything, would it? If I understand the terminology correctly, it would probably be something like -T !! The exposed-c-ps of the installation are connected directly to a local earth, and the transformer is not earthed at all, other than through the neutral to the intsallation's 'local' earth. It's almost TN-C-S in reverse, so maybe it's NT-C-SAnd what would you make of it if the point at which the conductor from the star point of the transfomer is tied down to physical earth and inititally separates into neutral and earth is not within the transformer room but actually in the consumers main panel? TNS or TNCS? the supply authority call it PNB but BS7671 doesn't recognise that...
Westie (or anyone), does the I/N/T/C/S terminology cater for PNB?
Is it common to have a CNE segment, other than very close to the transformer, in a TN-S service?
You tell me! I suppose that, in terms of the current path resulting from an L-E fault within the installation (which is probably the consideration of most importance) it's actually more like TN-C-S, in that the return path to the transformer is entirely along the N conductor. Which would you tick??So which box would you tick on your cert John as there there isn't a box for PNB
That's obviously the converse of what we've been talking about. Are you saying that the building concerned receives a TN-C-S supply which is not formally PMEd?SNE main, CNE branch into the building.
Are you saying that the building concerned receives a TN-C-S supply which is not formally PMEd?
SNE main, CNE branch into the building.
a TN-C-S supply which is not formally PMEd
CorrectAre you saying that the building concerned receives a TN-C-S supply which is not formally PMEd?
I seem to be getting some contradictory information here! Westie, if it is 'formally PMEd' where are the multiple earths?But it is!!a TN-C-S supply which is not formally PMEd
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