UK Type of Earthing System

[jmorton135]

Am i right in saying this is a TNC-S earthing arrangement?
The supply cable (which looks perished any advice on this welcome) comes from the wall in between the two houses (its a semi-detached). And no sign of it outside wall. So must be fed from underground. But there is a separate stranded cable that has earth sleeving on it and goes in to the MET which then also has the link wire to the Neutral terminal. Obviously I cant see any more of it it just goes into the wall. But it looks crap and undersized!

I am still training as an electrical engineer and Im interested to learn the donestic side (earthing systems, inspection and testing etc.) but it is my house. Probably going to ring YEB replace supply cable..
Thanks in advance for any comments!

 

[westward10]

It is all very well being inquisitive but taking the cover off the service head is not advised. One it is not your property and two that cable doesn't look in the greatest of condition and disturbing it could lead to a fault condition on it which is likely to lead to severe injury on your part.

 

[radiohead]

Possibly linked off next doors incomer, yes it's TNCS. And as above....you should not have removed the cover of the service head.

 

[bill01803]

It is writen on the cutout cover

 

[jmorton135]

Ok thanks guys. There was no seal on this cover. I was merely doing a safe inspection as it looked in a sorry state. But your advice has been noted and we are going to get them out to it. Thanks.

 

[davesparks]

Ok thanks guys. There was no seal on this cover. I was merely doing a safe inspection as it looked in a sorry state. But your advice has been noted and we are going to get them out to it. Thanks.

It doesn't matter whether it is sealed or not, you need to be aware that this equipment is the property of the DNO and you are not permitted to open it.

How did you establish that your inspection was safe? Did you have the correct PPE and training to work on this live equipment?

 

[pc1966]

This short video illustrates the advantage of the correct arc-flash PPE when working on live supply systems:

They appears to be OK afterwards, but the brownness of the trousers was not (thankfully) made clear.
View: https://www.youtube.com/watch?v=Z3yKFLJpnhI

 

[7029 dave]

That was very foolish to open up, please take advice given.

 

[Lister1987]

I could be wrong but You will have needed to take the fuse hoder out to access the screw that than gives access to the CNE terminal.



Having removed the fuse in the first instance (A no as everyone has stated...yes we know it happens but that doesn't make it OK. you then proceed to reinsert the carrier (presumably with fuse still in as there is no image to say otherwise) with LIVE PARTS exposed. Others have already stated on the PPE front and for good reason.

If you want to want to get to know the inside of a service head (and earthing arrangements and what they look like either;

1. Get on youtube and search; GSH Electrical does a few videos on what earthing systems look like on paper and how they appear in reality. John Ward (flameport.com) also does some good indepth content on the evolution of the cutout.

2. Get on eBay and the like and buy one that's been decom'd (if you're a tight-arse like me) and then play with it, hell; make yourself a mockup house on a sheet of MDF; cutout, isolator, consumer unit and whatever you want for final circuits. At least then you can explore safely.

Curiousity is great and all but it also killed the cat (unless the owner of said cat was Schrödinger in which case, the jury is still undecided on that one.

 

[Lucien Nunes]

I think the reason the cable looks manky is that it was previously terminated in a pitch-filled sealing chamber - note the wooden bung still attached - that predated the Series 5. The cutout was then replaced and the cable was melted out of the pitch, leaving it covered in black goop when the insulation itself might be fine.

Of course, you can't know what that bit looks like, because you didn't take the cover off.

 

[davesparks]

As has been pointed out already the sticker on the front of the cutout clearly tells you what type of earthing is there, PME so therfore it is TNCS.

And this just goes to reinforce the point I have often made, labels, stickers etc are a waste of time, nobody reads them or pays any attention to them

 

[UKPN]

As has been pointed out already the sticker on the front of the cutout clearly tells you what type of earthing is there, PME so therfore it is TNCS.

And this just goes to reinforce the point I have often made, labels, stickers etc are a waste of time, nobody reads them or pays any attention to them

It's PME. But, as I have to post more than 3 words, I will say it again, it's PME!