I know this is a DIY site and so this might be a little beyond what should be posted on here, however i'd really like some opinions on this!
Went to look at a system today, earthing arrangement appeared to be TN-S however the earth connection wasn't sweated onto the cable but connected via a earth clamp on the main incoming cable (Its the old lead/paper style).
I know these don't give a great connection to earth but i've also been told a million times that you aren't supposed to reapply them as you'll crush the cable contained within it.
The supply is via overhead lines though (which i assume is either TT or converted TNC-S?).
Anyway, tested Ze and got a reading of 1.54 ohms (obviously way too high for a TN-S).
This was a bit of a puzzler as i'd already tested Zs on the circuit i was working on before i'd started and it was well within 7671 limits. I re tested the entire DB circuit by circuit for Zs and all were well within tolerance.
I know parallel earth paths could be pulling the Zs readings down to within acceptable limits but its the overall Ze reading thats troubling me.
My question is.... Do i have a TN-S with a way too high Ze that the distributor needs to recitfy or should i convert it to TT (or is it already a TT with no electrode?) and install a electrode?
Hope someone can give me some useful advice
Went to look at a system today, earthing arrangement appeared to be TN-S however the earth connection wasn't sweated onto the cable but connected via a earth clamp on the main incoming cable (Its the old lead/paper style).
I know these don't give a great connection to earth but i've also been told a million times that you aren't supposed to reapply them as you'll crush the cable contained within it.
The supply is via overhead lines though (which i assume is either TT or converted TNC-S?).
Anyway, tested Ze and got a reading of 1.54 ohms (obviously way too high for a TN-S).
This was a bit of a puzzler as i'd already tested Zs on the circuit i was working on before i'd started and it was well within 7671 limits. I re tested the entire DB circuit by circuit for Zs and all were well within tolerance.
I know parallel earth paths could be pulling the Zs readings down to within acceptable limits but its the overall Ze reading thats troubling me.
My question is.... Do i have a TN-S with a way too high Ze that the distributor needs to recitfy or should i convert it to TT (or is it already a TT with no electrode?) and install a electrode?
Hope someone can give me some useful advice