Opinion on Supply System Type Wanted: TN-S or TN-C-S

[Ian1981]

The earth is separate in the supply cable to the neutral so TN-S

 

[Risteard]

Surely it must be TN-S as there appears to be a separate neutral and protective conductor. As there is no PEN conductor it can't be TN-C-S.

It's also in a bloody dangerous condition!

 

[UKMeterman]

Hi,
1. Why did you open the head? You have no right to do so and the older ones can and do go bang. (research arc flash).
2. When you did the the PEFC test did you isolate the installation, disconnect the earth cable from the terminal shown and test at that terminal?

 

[davesparks]

It's TNS, no testing necessary, just count the number of incoming conductors!

 

[westward10]

The neutral and cpc are not combined so TN-S.

 

[jlrb]

Thanks everyone for your input and help on this. Great forum and good advice.

 

[jlrb]

Hi,
1. Why did you open the head? You have no right to do so and the older ones can and do go bang. (research arc flash).
2. When you did the the PEFC test did you isolate the installation, disconnect the earth cable from the terminal shown and test at that terminal?

1. I did not open the head - I was not the photographer.
2. Yes I did. To avoid any chance of multiple earth paths.

 

[Devonchris]

I would go for TN-C-S.
If you look carefully at incoming supply, the concentric cable has only 2 conductors. The centre line conductor and outer stranded neutral. Part of the stranded neutral has been seperated and used to feed the earth terminal. (Effectively creating a link between them) the remaining strands have then been painted black to form the neutral conductor.

So to my eyesight, which is not what it was, it's combined in the service head, therefore TN-C-S.

 

[Ian1981]

I would go for TN-C-S.
If you look carefully at incoming supply, the concentric cable has only 2 conductors. The centre line conductor and outer stranded neutral. Part of the stranded neutral has been seperated and used to feed the earth terminal. (Effectively creating a link between them) the remaining strands have then been painted black to form the neutral conductor.

So to my eyesight, which is not what it was, it's combined in the service head, therefore TN-C-S.

The neutral and cpc are not combined in the service head and are separate split like the picture

 

[Devonchris]

Never seen cable like that Ian.
Having had another look I think your right.

 

[Lee42]

View attachment 37591

The neutral and cpc are not combined in the service head and are separate split like the picture

I would agree with that.
My father is a cable jointer for enw and have showed him the picture.
This was his reply
It looks like 16 or 26 mm single phase split cable or scne which is separately combined neutral & earth

 

[Ian1981]

I think it looks pretty cool

 

[The Ghost]

I reckon if that was TN-C-S then the earth would come out of the neutral block.

 

[westward10]

The picture from the OP really couldn't make it any more obvious.

 

[jlrb]

View attachment 37591

The neutral and cpc are not combined in the service head and are separate split like the picture

Thanks for the picture - that looks very much like the configuration in the image I originally posted. Just to clarify is the consensus still that this is TN-S?

This would align with the observation that the PEFC and PSSC are different.

Thanks again for very helpful insights from the forum.