Means of Earthing

[NoSparks]

In the EIC/PIR there is an entry for type of earthing (TN-C-S, TN-S etc), there is a similar question on the Test Schedual with the obvious implication that the two are different. So am I right in assuming that on the EIC/PIR the question applies to the origen (the service) and on the Test Schedule it applies to the DB being tested. and since TN-C is prohibited in the UK under Ed17, this will always be TN-S?

 

[andyb]

It could be TT

 

[zupos40]

In the EIC/PIR there is an entry for type of earthing (TN-C-S, TN-S etc), there is a similar question on the Test Schedual with the obvious implication that the two are different. So am I right in assuming that on the EIC/PIR the question applies to the origen (the service) and on the Test Schedule it applies to the DB being tested. and since TN-C is prohibited in the UK under Ed17, this will always be TN-S?

TN-C may be prohibited in the uk as you say under 17th Edition, but I come across it twice in my 30 years both on blocks of flats built in the 70th and wired in micc, and in some cases aluminium, once in Morden soth london and the other in hertfordshire in both case, the installations were installed during the oil crisis in the early 70s, both were a nightmare in that tenants had changed plastic accessiores and outlet for metal, at the time I was employed to go into void properties and check inspect test and replace all metal accessiories with plastic and place large label on CCU informing tenants that they could not use metal etc.

So on a periodic you could still find TN-C and T-T you may even find IT if it specialist and feed from a private supply or generator.

 

[NoSparks]

Those are good points. Thank you