Help on p.I.r.

[Shay butler]

Hi all*I am currently carrying out a p.I.r. On an old tn-s supplied house. The earthing conductor appears to be a multistranded 10mm steel conductor.it is connected to the suppliers lead sheath cable by a. Bs 951 clamp and goes into the m.e.t. The ze is 0.13 ohms .although this is a good reading I am unsure where I stand with regards to the steel earthing conductor as there is not much information about this area. I no the bs 951 clamp is not permitted. Any help on the topic would be appreciated.*

 

[malcolmsanford]

The BS 951 clamp on the DNO cable is really down to you deciding wether you want to call them and let them know what you found, and most likely you will just get an " oh OK " and that will be the end of it. Of course if you told them it was hanging off they would then have to do something about it, which most likely would be either reattach the BS 951 clamp or if available charge you to upgrade the system to TNC-s, so that's basically leave as if.

Table 54.1 of the BS 7671-2008 tells us that a steel earthing conductor is 10mm if protected against mechanical damage, so I guess as it's just open to air you could code it a 4, but to be honest if I was getting that good a Ze again I would most likely not do anything.

 

[Shay butler]

so if I put a comment on the p.i.r. that the earthing conductor is attatched to the supliers cable by a bs 951 clamp and although ze is acceptable at the moment it may be affected in the future this will be sufficient?

Furthermore, I forgot to mention the multi stranded steel earthing conductor does not have any insulation. So if i gave it a four on the observations section this will also be ok?


I'm quite intrested to know how common, if at all, steel wire being used for earthing conductors is??


Thanks people