TN-S or TN-C-S

[johnnycash126]

Argument currently raging at work can only be settled on this forum.

We are a large company who has our own 11kv transformers and switches.At each transformer,the star point of each is connected to earth.From these transformers,we are then fed a 5 wire 415v system,each wire being seperate.
At the LV side,we do not have any combined conductors.

Now,is this a TN-S system or is it a TN-C-S.?

 

[ipf]

TN-S from the description.

 

[ipf]

:wink5:Taken long enough, man in black (2010)

 

[44ALLAN]

Argument currently raging at work can only be settled on this forum.

We are a large company who has our own 11kv transformers and switches.At each transformer,the star point of each is connected to earth.From these transformers,we are then fed a 5 wire 415v system,each wire being seperate.
At the LV side,we do not have any combined conductors.

Now,is this a TN-S system or is it a TN-C-S.?

Is the argument among the blacksmiths or the plumbers

 

[Bobster]

You will still have neutal>earth links at the Tx or at the main incoming panel.

it will be classes as Tn-s

 

[johnnycash126]

I think we are a TN-S system but we have been told its a TN-C-S ,probably a historic comment from somone who shouldnt have been here in the first place.

 

[Darkwood]

Its a TNS; C is for combined which dosn't apply to the tap itself but the wiring system.. i can't see why there is a debate about this just look up the definitions in the reg's or OSG even got pretty pics to illustrate it.

 

[johnnycash126]

Looking at it now and this has been shown to all but still certain individuals wont accept it.I suppose word of mouth is king here.Thanks

 

[44ALLAN]

Looking at it now and this has been shown to all but still certain individuals wont accept it.I suppose word of mouth is king here.Thanks

What don't they understand about the words 'combined' and 'separate' ?
Are these people sparks?

 

[Engineer54]

The confusion comes from grounding the TX neutral. This is more often than not, undertaken for practical reasons at the main LV switchboard. Those that are not aware, will often confuse the N-E link connection as being a TNC-S connection. But it's extremely rare for a MV/LV TX supplied installation to be TNC-S....

 

[44ALLAN]

The confusion comes from grounding the TX neutral. This is more often than not, undertaken for practical reasons at the main LV switchboard. Those that are not aware, will often confuse the N-E link connection as being a TNC-S connection. But it's extremely rare for a MV/LV TX supplied installation to be TNC-S....

I can see that happening and yes that would be confusing to plebs like myself
But surely it would be labelled as such in the LV switchgear?

 

[Norwich]

TNS no doubt at all black and white

 

[44ALLAN]

TNS no doubt at all black and white

mmmmm so you look at your main incoming cable/cables in your main switch and the neutral is bolted/connected directly onto earth as has been stated is sometimes done............how would you say that is TN-S?

 

[Engineer54]

I can see that happening and yes that would be confusing to plebs like myself
But surely it would be labelled as such in the LV switchgear?

Sometimes it is labelled, but certainly not always!!

 

[44ALLAN]

Sometimes it is labelled, but certainly not always!!

That would be confusing then................a TN-S system with the neutral bonded to earth in the main incomer screaming TNC-S at you.

I'm coming back as a joiner or a plumber...............NOT