Earthing system quiz

[Simon47]

Is the link between the neutral and earth terminal in the cut out still in place ?

Must admit, I was wondering if it was fitted, or had ever been fitted.

I think you are assuming too much competence on behalf of the meter fitter!

Probably
As I recall, when I had an isolator fitted, the guy didn't take any measurements at all - only a quick check of polarity.

I thought it was quite obvious that the earth was unconnected, as it isn't a main cable entering the head, just two cores, line and neutral - is it fed from overhead lines, or is there a proper intake head somewhere?

TN-C-S is like that. Just two cores in which may be separate cables overhead, or concentric (buried or overhead). Inside the service head (a.k.a. main fuse unit) the earth terminal is linked to the neutral conductor. Out in the street, there will be multiple points where the neutral is earthed - hence the name "PME" (protective multiple earthing).
As long as the neutral conductor doesn't get broken, this does give a very good earth.

 

[Burtones]

After a few words of bemusement they 'converted' it to PME for me.

So what did they do, just link the earth terminal to neutral in the cut out?

 

[Julie.]

Must admit, I was wondering if it was fitted, or had ever been fitted.

Probably
As I recall, when I had an isolator fitted, the guy didn't take any measurements at all - only a quick check of polarity.

TN-C-S is like that. Just two cores in which may be separate cables overhead, or concentric (buried or overhead). Inside the service head (a.k.a. main fuse unit) the earth terminal is linked to the neutral conductor. Out in the street, there will be multiple points where the neutral is earthed - hence the name "PME" (protective multiple earthing).
As long as the neutral conductor doesn't get broken, this does give a very good earth.

But that isn't configured as as a main intake head aka service head, there would naturally be no connection between the neutral and earth connection.

That could be configured for TT, or TN-C-S, but it isn't configured for anything!

So T at best!

Even if it does end up being interconnected for TN-C-S, given the age of the cable it isn't necessarily PME

 

[Zerax]

So what did they do, just link the earth terminal to neutral in the cut out?

Exactly !

 

[Zerax]

Is it ohl, or is the a proper head somewhere?

That is the proper head... it's a very normal terraced house with nothing else weird or whacky.

 

[ipf]

Exactly !

So, is it PSE......Protective Singular Earthing? ? ?

Where is the incoming cable...be interesting to it in full.

 

[Simon47]

But that isn't configured as as a main intake head aka service head, there would naturally be no connection between the neutral and earth connection.

I think I must have lost track of the thread here.
Looking at the photo posted by Zerax, I can't see whether there's an E-N link installed or not. It's not an area (features of different types of service head) I have much experience with, and the ones I have seen inside don't have the presence or otherwise of the link particularly obvious (if visible at all).

But if TN-C-S, all it would have is two cables (or two cores in one cable), with the N-E link fitted to provide the earth connection. So I don't get your comment that "it's obvious there isn't an earth as there's only two single cables". Our connection at church is "just two cables", and that's PME/TN-C-S - looking at the photos I have, looks distinctly similar to Zerax's photo, two cores in, two cores out, and an earth block on the side (confirmed during a DNO engineer visit to be PME linked).

 

[Mike Johnson]

I agree, but think most of us on here where too afraid to question the fact that there is an obvious earth visible. I NEED THE SMILIES BACK.

 

[ipf]

I agree, but think most of us on here where too afraid to question the fact that there is an obvious earth visible. I NEED THE SMILIES BACK.

Just right click on your message page....

 

[Mike Johnson]

??? Ohh thanks ipf.

 

[Simon47]

Right click where ? Do you mean in the composing box ?