TN-C-S or TN-S?

[dsuley]

Hi everyone,
Just wanting to confirm something, could you please let me know if these pictures are describing a TN-S or TN-C-S system?
Thanks in advance

Untitled

• dsuley
• 2 Jun 2011
• 1

Untitled

• dsuley
• 2 Jun 2011
• 2

 

[flyingsparks]

There both TN-S.

 

[Adam_151]

No, the second one is TN-C-S, although it looks like it was probably TN-S originally, and then a repair to the street main caused everything to become TN-C-S and they went and stuck labels on, often they don't bother to label!

 

[dsuley]

There both TN-S.

Thanks for your reply, I thought they were TN-S too. But in the 2nd picture it's a customer's house where they had no earth, so we requested the DNO put in a
PME, which they did, and a PME is described as Protective Multiple Earthing System, which sounds like a TN-C-S? and this picture is showing the situation after a PME was put in.
So I'm not sure now, which is why I decided to ask you guys.
Thanks

 

[dsuley]

No, the second one is TN-C-S, although it looks like it was probably TN-S originally, and then a repair to the street main caused everything to become TN-C-S and they went and stuck labels on, often they don't bother to label!

Thanks for your reply.
The 1st picture is showing a previous job I did, and I thought that was a TN-S and then I came across this second job and that's a TN-C-S system, and from what I understand, both these systems are the same they look like the same thing is happening, could you please explain how I can tell they are different? I would appreciate that.

 

[flyingsparks]

TN-C-S and PME is the same thing..

 

[dsuley]

TN-C-S and PME is the same thing..

these pictures are describing a TN-S or TN-C-S system?

Read more: //www.diynot.com/forums/viewtopic.php?t=277199#ixzz1O98tTpNx

 

[ChrisRogers]

TN-C-S and PME is the same thing..

no they are not, PME can exist on TN-S networks

 

[AndyPRK]

So what with the 60A only fuse label ?

Is the supply cable only rated to that ?

 

[flyingsparks]

Yep, I didnt read that notice on picture 2!

 

[dsuley]

So what with the 60A only fuse label ?

Is the supply cable only rated to that ?

No idea! on the original fuse it says 100A, but the fitter had just stuck that label on and left it, and on the invoice he'd written 60A too. and in the invoice there's no mention of TN-S or TN-C-S

 

[dsuley]

TN-C-S and PME is the same thing..

no they are not, PME can exist on TN-S networks

Could you please explain to me how that can happen? as I'm confused, I thought that a PME could only be on TN-C-S I would really appreciate your guidance.
Could you also help me with distinguishing between the 2 pictures? because everyone's saying different things and I'm even more confused now, as far as I can see the 2 pictures are showing the same sort of system.

 

[kai]

Where is the earth connection on the second grey fuse unit? - normally it comes out of the right hand side of the fuse unit in the case of a TNCS or PME type system. This "right hand side earth connection" convention has been found on my former 1968 built house, and also on my new Twenty-teens new build house.

 

[ricicle]

Looks like they've took a few strands of the neutral part of the concentric cable for the earth. To my mind that would make the neutral undersize at the cut-out. (unless concentric neutrals are oversize anyway)

 

[studentspark]

Sorry, but where is the earth on the second photo?

It looks to me like a TNS but not connected up!