Type of earthing system? | on ElectriciansForums

Discuss Type of earthing system? in the UK Electrical Forum area at ElectriciansForums.net

newfutile

-
Nearly Esteemed
Arms
Supporter
Joined
Aug 30, 2011
Messages
549
Reaction score
442
Location
hemel hempstead
What type of earthing system is this?
 

Attachments

  • [ElectriciansForums.net] Type of earthing system?
    7B6B5761-96A8-4078-9C0F-E061CF154FDC.jpeg
    317.4 KB · Views: 204
This one causes confusion
SNE = separate neutral and earth
The sticker looks fairly recent and I’d put a fiver on TNS
Last time I had this I measured pscc and pefc and found them sufficiently different to conclude it was certainly TNS.
 
I was about to say splitcon? In which case you may not detect difference.
I guess next thing is to look at reasons it might mattter since you are below tncs threshold anyway.
Is main earth/bond at least 10mm?
Any relevant special locations or car charger about to be installed?
I see no reason not to believe the sign anyway!
 
Is this in a flat as the red fuse holder would suggest it's a solid link and it's fed from a Ryefield or similar distribution set up
Could be like my flat: TN-S at the head (red link) but seems to be TN-C-S at the Ryefield (actually Lucy) board down in the hallway.

Determining TN-S or TN-C-S by measurement is hard to do. If the PEFC is much lower than the PSCC then it is clear, but on split con cable back to some linked point both N & E are often identical conductors so your measurements will be very similar.

If you have a low-ish PFC, so Ze in the 0.3 ohm or more region, then you have a sporting chance of measuring N-E resistance (with care, power off but at input of isolator, MET not bonded to avoid links via service pipes, etc) to see if it is comparable to Ze (so a long length of N linked to E way back and similar to the estimated L distance/impedance). If you get near-zero then it is clearly linked at the cut-out! Here having Ze near 0.1 is surprisingly low hence my original though about where the N-E link really is (as it is always linked somewhere/somehow).

But as I found in my flat being TN-S at the cut-out is no guarantee that are not really on a PME supply. However, they say SNE so TN-S and unless it is ground floor for EV charger, etc, it is simpler just to go with that!
 
They are flats fed from a Lucy board i am conducting an EICR for the communal areas , just wondered what box to tick ? Although i have been told almost everything is PME at some point these days.
 

Reply to Type of earthing system? in the UK Electrical Forum area at ElectriciansForums.net

News and Offers from Sponsors

  • Article
Join us at electronica 2024 in Munich! Since 1964, electronica has been the premier event for technology enthusiasts and industry professionals...
    • Like
Replies
0
Views
438
  • Sticky
  • Article
Good to know thanks, one can never have enough places to source parts from!
Replies
4
Views
1K
  • Article
OFFICIAL SPONSORS These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then...
Replies
0
Views
1K

Similar threads

Hi all. Try to keep this nice and short. Had an EICR fail on a health centre due to corrosion on main supply which was causing high Ze values...
Replies
0
Views
148
It's not the same scenario, though. Tails more than 3mtrs can be overcome by using a fused switch and rcd board, whether the earthing system is...
2
Replies
18
Views
827

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

YOUR Unread Posts

This website was designed, optimised and is hosted by untold.media Operating under the name Untold Media since 2001.
Back
Top