TN-S or TN-C-S

Elidor · May 13, 2011

Morning all,

The earthling arrangements in our house have what looks like a TN-C-S distributors cut out enclosure but has no earth wire where the earth wire should be. Instead there is a small cut-out on the bottom left corner and what looks like 5 or 6 heavy strands of uninsulated copper coloured cable running straight into MET.

Are these strands the armour of the cable implying it’s a TN-S?

Adam W · May 13, 2011

I would have said it's TNCS by the way the earth conductor comes out of the supply head - with TNS you can usually see it clamped to the cable.

High Tower · May 13, 2011

My guess would be TNC-S, Ze should confirm it

BillyTheSparks · May 13, 2011

Elidor said:
Are these strands the armour of the cable implying it’s a TN-S?

With that type of supply cable I would say that those wires are the outer conductor of the cable (i.e the Neutral). As that cable will have a single core (usually aluminium) as the phase; and copper wires wrapped around it (like SWA) which is the Neutral.

So I would say it is TNC-S although I'd prefer to see a seperate earth cable going into the supply head and not having a few strands of neutral wires seperated from the neutral connector in the head.

If all that makes sense!!

IQ Electrical · May 13, 2011

Elidor said:
Morning all,

The earthling arrangements in our house have what looks like a TN-C-S distributors cut out enclosure but has no earth wire where the earth wire should be. Instead there is a small cut-out on the bottom left corner and what looks like 5 or 6 heavy strands of uninsulated copper coloured cable running straight into MET.

Are these strands the armour of the cable implying it’s a TN-S?

View attachment 5599 View attachment 5598

As above, my initial guess would be TN-C-S but if that is the twisted strands of concentric cable then there's a good chance that it is TN-S.

Carry out a Ze test and then a neutral loop test at the origin and if the figures are virtually identical than you have a TN-C -S system.

Engineer54 · May 13, 2011

IQ Electrical said:
As above, my initial guess would be TN-C-S but if that is the twisted strands of concentric cable then there's a good chance that it is TN-S.

Carry out a Ze test and then a neutral loop test at the origin and if the figures are virtually identical than you have a TN-C -S system

That would be my guess too, as there seems to be an accommodation for a neutral earth connection incorporated in the cut out head.... Never seen a box like this for an earth connection mind, and can't really see a reason for that box either!!!

telectrix · May 13, 2011

strange set up. if you meassure pscc and pefc , and they are identical, then you have TNC-S.

Electricalserv · May 13, 2011

What an absolute bodge job. Cracked cover with screw missing.... unsheathed cable....Id say its a TNC-S with the set up but it could well be a TNS. There was a picture uploaded not long ago similar to this....When the plate of the cutout was removed it was quite easy to see the earth and neutral where seperate and it was indeed a TNS.

baldsparkies · May 13, 2011

Electricalserv said:
What an absolute bodge job. Cracked cover with screw missing.... unsheathed cable....Id say its a TNC-S with the set up but it could well be a TNS. There was a picture uploaded not long ago similar to this....When the plate of the cutout was removed it was quite easy to see the earth and neutral where seperate and it was indeed a TNS.

Agree with others regarding PME, If thats an ABSOLUTE BODGE JOB by definition though, what the hell are we going to call the ABSOLUTE BODGE JOBS of the world.

There be much worse than that out there.

Electricalserv · May 13, 2011

baldsparkies said:
Agree with others regarding PME, If thats an ABSOLUTE BODGE JOB by definition though, what the hell are we going to call the ABSOLUTE BODGE JOBS of the world.
There be much worse than that out there.

Agreed, for the cutout supplied by the DNO its an absolute bodge

telectrix · May 13, 2011

that's what happens when you train up monkeys.

Engineer54 · May 13, 2011

Why are you all convinced that this set up is TNC-S?? Look at the cut out head again, if this was going to be a neutral earth set up, the earth would be exiting out of the ''add-on'' portion, next to the point where the neutral cable exits the cut out head. No, i'm pretty sure this is a TN-S supply, and is why the cable is bare, and exiting the cut out where it is....

Electricalserv · May 13, 2011

Engineer54 said:
Why are you all convinced that this set up is TNC-S?? Look at the cut out head again, if this was going to be a neutral earth set up, the earth would be exiting out of the ''add-on'' portion, next to the point where the neutral cable exits the cut out head. No, i'm pretty sure this is a TN-S supply, and is why the cable is bare, and exiting the cut out where it is....

I agree mate, I said I wasn't 100% sure but I've seen TN-S look like this. Remove the plate and u'd be able to tell.

madmac · May 13, 2011

Electricalserv said:
What an absolute bodge job. Cracked cover with screw missing.... unsheathed cable....Id say its a TNC-S with the set up but it could well be a TNS. There was a picture uploaded not long ago similar to this....When the plate of the cutout was removed it was quite easy to see the earth and neutral where seperate and it was indeed a TNS.

Also looks like there's an exposed live conductor underneath the meter! That's what happens when mobs put guys on price work!!! They just batter them in like there's no tomorrow and we wonder why standards and workmanship in the industry are declining!!!

IQ Electrical · May 13, 2011

Engineer54 said:
Why are you all convinced that this set up is TNC-S?? Look at the cut out head again, if this was going to be a neutral earth set up, the earth would be exiting out of the ''add-on'' portion, next to the point where the neutral cable exits the cut out head. No, i'm pretty sure this is a TN-S supply, and is why the cable is bare, and exiting the cut out where it is....

Lol, did you not see my post?
Looks like TN-S on split concentric to me!

TN-S or TN-C-S

Elidor

Adam W

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IQ Electrical

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