How rare is the TN-C Earthing system past the DNO property?
- Thread starter eveares
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AIUI, it's not allowed, at least, not in UK - i.e. CNE conductors are not allowed within UK installations.
Kind Regards, John
Correct - it's permitted in some circumstances by BS7671 but prohibited by ESQR 2002 - see BGB pg 164 reg 543.4
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A colleague's son found an electric heated shower where the neutral, earth and water all shared the same hollow copper "wire" in a temporary worker's hostel when he was helping to construct a school building in a third world country.
It was used as Earthed Concentric Wiring using single-core MICC wiring, I think in the 1930s ...
I think from 14th or was it 15th Edition it was prohibited on mains supplies but permitted on privately generated supplies, and from 17th Edition prohibited on privately generated supplies? But I could be wrong.
I think from 14th or was it 15th Edition it was prohibited on mains supplies but permitted on privately generated supplies, and from 17th Edition prohibited on privately generated supplies? But I could be wrong.
I thought it was still permitted in mines? But not allowed anywhere else.
I wouldn't think so, TN-C-S isn't allowed at source for anything other than office buildings if I remember the regulations and ACOP correctly.
When I was at college a lecturer said he had been involved with the install of TNC system in a block of flats while he was an apprentice..... Wired in pyro so that must be at least 50 years ago
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Define supply network as clearly some large factories have quite a large supply network within the factory. The steel works where my father worked had a larger generating capacity than the local power station.
OK today 12MW seems rather small compared with the twin 600MW of Sizewell or the quad 400MW of Connah's Quay but these in house generators are often not 400 volt but run at 3.3 or higher and once we look at these systems I would not be at all surprised to see TN-C systems.
Personally Algeria working for NACAP bv is the only time I have seen TN-C used and I think that was all down to one Turkish electrician Dutch speaking who could not understand the difference between earth and neutral.
I am sure there are many more instances where some guy who thinks he knows it all has used TN-C even though it should not have been used.
OK today 12MW seems rather small compared with the twin 600MW of Sizewell or the quad 400MW of Connah's Quay but these in house generators are often not 400 volt but run at 3.3 or higher and once we look at these systems I would not be at all surprised to see TN-C systems.
Personally Algeria working for NACAP bv is the only time I have seen TN-C used and I think that was all down to one Turkish electrician Dutch speaking who could not understand the difference between earth and neutral.
I am sure there are many more instances where some guy who thinks he knows it all has used TN-C even though it should not have been used.
Gets used in street lighting a lot, particularly when installed by a DNO type company.
A church yard near me had to adopt the street lighting, and it was wired with twin uninsulated overheads spanned between wooden poles, a standard street light fitted to each pole.
When they asked to get it re-connected to their electricity supply, there were many a discussion on what to do.
A church yard near me had to adopt the street lighting, and it was wired with twin uninsulated overheads spanned between wooden poles, a standard street light fitted to each pole.
When they asked to get it re-connected to their electricity supply, there were many a discussion on what to do.
http://talk.electricianforum.co.uk/topic/21357-micc/?p=294903
I believe there one of the large department store chains also has a number of sites wired in a similar style
I have the newer version of them molegrips, that crimps a 3 point seal
As do tramways. Running rails are a combined neutral and earth, overhead wire or third rail is the live conductor.
IIRC operators of "electric guided transportation systems" (railways, tramways etc) have an explicit exception to the "no TNC" rule in the ESQCR.
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