Supply earthing type

[john_s]

I hope you'll indulge my curiosity... I've been reading about earthing types, and wondered what type we have supplying the office here (photo attached).

Is it TNS or TNCS?

Or is it not possible to tell without taking the cover off? (Which I've no intention of doing)

It's fixed at floor level, so I can't see anything of the cables feeding into it.

Cheers.

 

[sparkytim]

Could be either with those Service heads

Your main Earthing conductor going into the RIGHT hand side connects onto a terminal within, which can have a seperate Earth feed coming in at the bottom but as this has been encased in concrete it is out of sight.

That termninal can also be linked the Nuetral connection for PME.

What may give you an idea is if the Ze ( L-E) is equal to a L-N Loop test reading at the Consumer Unit then it is probably TNCS if the P-E reading is higher then it Porbably is TNS

 

[initforthemoney]

Its PME.

 

[ianmacd]

Its PME.

And you can state that fact because?

a) You installed it so you know

B) you opened up the head

c) You guessed it and have no information about the installation at all but roled it up as fact

I'm guessing c myself.

 

[initforthemoney]

And you can state that fact because?a) You installed it so you know

B) you opened up the head

c) You guessed it and have no information about the installation at all but roled it up as fact

I'm guessing c myself.

a) No.

B) No.

c) No.

So you are saying that the OP has posted a picture to find out what it is, but then when we tell him, wont believe anyone?

I still say it is though.

 

[ianmacd]

No you believe its TN-C-S (as there is no presentation called PME) but the inferrence was that you were stateing a fact.

 

[green-hornet]

Its PME.

a) No.

B) No.

c) No.

So you are saying that the OP has posted a picture to find out what it is, but then when we tell him, wont believe anyone?

I still say it is though.

It is impossible to tell from that picture, the service head and cables are hidden from view, the head by the protective covers, and the cables by concrete. The only way to be sure is by testing as sparkytim has said in his post. That is of course without removing any parts you should not be touching.

For safety's sake I do hope you never presume when your on a job.

 

[spinlondon]

You could possibly contact the distributer and ask them.

 

[steptoe]

Im with initforthemoney on this,

I can tell using my special x-ray computer screen it is definately TT.

or it should be, if I installed it,

so I suppose Im not in agreement with initforthemoney cos he reckons he installed a PME system.

sorry OP,

as has been said, without doing some tests it is both impossible and would be unethical of us to state which type of earth you have,

we could have reasoned guesses, but they will invariably be one of the two systems you stated so will therefore be no further on in your investigation.

my only suggestion would be to try and see what size earth you have from the cut out(its usually stamped on it),

having a look at your pic it looks like 10mm earth which may suggest TNCS if the neutral is 16mm.

but that is in no way a definitive answer.

 

[initforthemoney]

so I suppose Im not in agreement with initforthemoney cos he reckons he installed a PME system.

Where have i stated that i have installed PME?

In case you were unaware, this can only be done by the DNO.

 

[initforthemoney]

No you believe its TN-C-S (as there is no presentation called PME) but the inferrence was that you were stateing a fact.

Whatever a presentation is....

There is however, a supply type known as PME.

 

[kme]

But, as has been said by all other respondants on the matter, it could be TN-S either. You cannot tell any better than the rest of us, unless you have more knowledge of this particular installation than the rest of us.

Take a cool down pill IIFTM, you are being far too contentious (in this and other threads).

n.b. regarding the O/P - as the guys have said, it could be either. Sparky tim has given the best well to determine by measurement, or go with spin and ask the DNO.

I`d have actually guesstimated TN-S; purely because I cannot see any evidence of a PME label.

KME

 

[steptoe]

But, as has been said by all other respondants on the matter, it could be TN-S either. You cannot tell any better than the rest of us, unless you have more knowledge of this particular installation than the rest of us.Take a cool down pill IIFTM, you are being far too contentious (in this and other threads).

n.b. regarding the O/P - as the guys have said, it could be either. Sparky tim has given the best well to determine by measurement, or go with spin and ask the DNO.

I`d have actually guesstimated TN-S; purely because I cannot see any evidence of a PME label.

KME

but,

havent I already been told that it may still be TNCS,

even though I advocated the fact that (it used to be ) will only be PME if a label is present.

Im not sure who put it to me, but they quoted ESQCR as stating (in their supply amendment) that all TNCS from 2003(?) was in fact PME administered(hard to believe for me at least!)

initforthemoney you stated it was PME ,

with NO explanation as to why or why not,

another poster stated unless you installed it you cannot stae that as fact, I agree with the second poster,

you cannot state PME as a fact,

IMHO even if you can prove it is TNCS without having it in writing to show me you still cannot state PME.

PME is a means of earthing, not a means of supply.

 

[initforthemoney]

So no one has noticed the g/y going into the side of the cutout?

PME/TNCS are the same thing.

 

[Manator]

So no one has noticed the g/y going into the side of the cutout?PME/TNCS are the same thing IMO.

So where is this Y/G cable connected to?

Is the neutral block bridged or open?

 

[initforthemoney]

will only be PME if a label is present.

This also not strictly correct.

I have been to many, many properties with no labels.

 

[a1spark]

John, as has already been pointed out and as referred to in your post,,,i,e.

Or is it not possible to tell without taking the cover off? (Which I've no intention of doing).....The answer was already within your question.

inforthemoney , I can see your point that it resembles a tncs connection ,but this photo in itself cannot positively identify that fact, ..the Earthing cable could be linked to the incoming Neutral....or it could have a link out of sight to the cable sheath [ or even an Earth rod }..or it could simply be Parked inside with no connection to anywhere.....impossible to say which on the evidence available wouldnt you agree ?

 

[steptoe]

So no one has noticed the g/y going into the side of the cutout?PME/TNCS are the same thing.

NO they are NOT,

not even on the basis of a UK only forum,

can you please quote me where in any supply document that is statutory it states this fact.

This also not strictly correct.I have been to many, many properties with no labels.

I agree

John, as has already been pointed out and as referred to in your post,,,i,e.Or is it not possible to tell without taking the cover off? (Which I've no intention of doing).....The answer was already within your question.

inforthemoney , I can see your point that it resembles a tncs connection ,but this photo in itself cannot positively identify that fact, ..the Earthing cable could be linked to the incoming Neutral....or it could have a link out of sight to the cable sheath [ or even an Earth rod }..or it could simply be Parked inside with no connection to anywhere.....impossible to say which on the evidence available wouldnt you agree ?

agreed,

I told you it was TT.

 

[Sidewinder]

Steps,

Come on, you know that in the UK it is illegal for a DNO to supply TN-C-S unless it is PME.

We've been through this!

The supply presentation is TN-C-S. However, the DNO is required to make any CNE supply system PME or PNB (with limitations).

:coat

BTW, Could be NT-C-S or TN-S depending on the configuration of the cut out, however, I'd bank on TN-C-S as the N & E emerge from the cutout.

HOWEVER, NO PME label!...

Here we go again!

Paul.

 

[kme]

So no one has noticed the g/y going into the side of the cutout?

Without getting into the second part of your post.......again... (Al...bert.....)

I`m pretty sure EVERYBODY saw that; otherwise they couldn`t have made a suggestion.

KME