Earthing Arrangement- confused

[ianmacd]

Not quite heard it described that way before.I have heard distributed as TN-C, and made available as TN-S before now.

As you say combined and then separated.

How does that work then as the PE and N are separate from source on TN-S and combined into a PEN on TN-C?

 

[steptoe]

Not quite heard it described that way before.I have heard distributed as TN-C, and made available as TN-S before now.

As you say combined and then separated.

it enters the cut out as TN-Combined,

and you remove it as Separated on the consumer side,

so yes, the installation is TN-S (just the same as cable sheath supply throughtout), but it is presented as TN-C-S, remember, the supply company, and the metering/cut out owner is not always the same people nowadays.

 

[spinlondon]

How does that work then as the PE and N are separate from source on TN-S and combined into a PEN on TN-C?

Is TN-S a distribution system or an earthing system?

I seem to recall you stated something about TN-C-S not being a distribution system, and something else about BS7671 not applying to distribution systems.

 

[ianmacd]

Is TN-S a distribution system or an earthing system?I seem to recall you stated something about TN-C-S not being a distribution system, and something else about BS7671 not applying to distribution systems.

I'm sure one day you will grow up but until then I think my question was self explanatory but as you seem to be unable to grasp simple things then lets try this.

How can a TN-S be the earthing system if the distribution is TN-C?

 

[spinlondon]

I'm sure one day you will grow up but until then I think my question was self explanatory but as you seem to be unable to grasp simple things then lets try this.How can a TN-S be the earthing system if the distribution is TN-C?

Don't know, thought perhaps you would clarify things.

For instance if as you appear to be stating the distribution system is TN-C, what would be the earthing system?

 

[ianmacd]

Don't know, thought perhaps you would clarify things.For instance if as you appear to be stating the distribution system is TN-C, what would be the earthing system?

You claim to have seen it as TN-S. I was asking how that is possible.

 

[spinlondon]

You claim to have seen it as TN-S. I was asking how that is possible.

Oh dear, no I have not made such a claim.

 

[PBC_1966]

I don't think you can really say that TN-S (or any other arrangement) is a distribution system or an installation system alone.

By its very nature, the designation contains elements of both. The first "T" specifies that the system is solidly earthed at source, which is clearly part of the distribution system. The second letter - either "N" or "T" - specifies how the installation's earth is derived.

You could take an older distribution system with separate metallic earth path back to the transformer, but the entire combination of distribution system and consumer's installation is only going to be TN-S if the installation uses the DNO's earthing facility. If the installation has its own earth rod (alone), then it becomes TT by definition, since there is no solid metallic path for earth fault currents.

By the same token, you can't say that a PME distribution system in which the neutral can be used as a PEN is TN-C-S, since the "N" refers to the way in which the installation derives its earth. Again, the whole setup is only TN-C-S where the DNO's earthing facility is used. As in many of the houses around here, if the installation is earthed solely to a local electrode, then the combination of distribution system and consumer's installation becomes TT, regardless of the fact that the DNO's distribution system is PME.

These new TN-S/TN-C-S/TT designations seem to have caused a lot of confusion, but because each one refers to elements of both the distribution system and the consumer's installation, you can't really use any of them to refer to one or the other in isolation.

 

[kme]

I, for one, am now officially off this thread.

I just don`t care anymore......

:good night: bad day explode :coat

 

[ianmacd]

Not quite heard it described that way before.I have heard distributed as TN-C, and made available as TN-S before now.

As you say combined and then separated.

Oh dear, no I have not made such a claim.

So whats that then?

 

[spinlondon]

So whats that then?

Why do you insist on spouting nonsense?

 

[PBC_1966]

I have heard distributed as TN-C, and made available as TN-S before now.

TN-S means that the protective earth is separate all the way back to the source. If any part of the system uses a combined PEN, then it can't be TN-S. If your installation is earthed to the supplier's PME neutral, then you have TN-C-S.

The only way to get TN-S from that would be to create a separately derived system from a transformer, then you could make your secondary side TN-S.

 

[ianmacd]

Why do you insist on spouting nonsense?

You seem to have a serious issue. You can not even admit what you have already written when its quoted back. Your contribution to most threads seems to be counterproductive. Are you actually a moderator on screwfix trying to get people back there?

 

[kme]

Are you actually a moderator on screwfix trying to get people back there?

ROTFWLROTFWLROTFWL

Classic. Probably a serious question on your part, Ian, but FFSGuinnessGuinnessGuinnessGuinness

(n.b. They`re MINE!)

Guinness ] Guinness ] ROTFWL :coat

 

[steptoe]

ROTFWLROTFWLROTFWLClassic. Probably a serious question on your part, Ian, but FFSGuinnessGuinnessGuinnessGuinness

(n.b. They`re MINE!)

Guinness ] Guinness ] ROTFWL :coat

sometimes its so close it could be.

Applaud Smiley Applaud Smiley Applaud Smiley Applaud Smiley

Guinness Guinness Guinness Guinness Guinness

and please can we have the smilies stay in the same place. headbang

 

[spinlondon]

You seem to have a serious issue. You can not even admit what you have already written when its quoted back. Your contribution to most threads seems to be counterproductive. Are you actually a moderator on screwfix trying to get people back there?

I have no problem admiting that I have written something when it is quoted back.

I have a problem when somebody doesn't bother to read what is posted and then misquotes it, as in your case.

I posted as you have correctly quoted:

Originally Posted by spinlondon Not quite heard it described that way before.

I have heard distributed as TN-C, and made available as TN-S before now.

As you say combined and then separated.

You then posted this:

Originally Posted by ianmacd You claim to have seen it as TN-S. I was asking how that is possible.

Where in my post do the words "seen it as TN-S" appear?

I said that I have heard it described, I didn't say that I have seen it.

It seems that you are unable to post anything other than nonsense.

 

[green-hornet]

Posts like these really do not help anyone.

If misunderstandings occur which they often do then say politely that you may have misunderstood.

I am 49 years old and I learn something new everyday, when I started in this game lead cables where still in use and where the type of wiring that we used to have to pull out, to rewire.

I have been there seen it and worn the T shirt and yet a snotty 16 year old apprentice can teach me something new.( sorry all you snotty teenagers)

The purpose of debate is to find a solution or a compromise of different values, if during a debate you feel that no solution has been found to your satisfaction then all you are left to do is to stand by your beliefs, and agree to disagree.

 

[spinlondon]

Posts like these really do not help anyone.If misunderstandings occur which they often do then say politely that you may have misunderstood.

I am 49 years old and I learn something new everyday, when I started in this game lead cables where still in use and where the type of wiring that we used to have to pull out, to rewire.

I have been there seen it and worn the T shirt and yet a snotty 16 year old apprentice can teach me something new.( sorry all you snotty teenagers)

The purpose of debate is to find a solution or a compromise of different values, if during a debate you feel that no solution has been found to your satisfaction then all you are left to do is to stand by your beliefs, and agree to disagree.

I'm not certain whether Ian's misunderstanding is genuine?

It would appear from other posts on this thread and other threads that he is deliberately attempting to wind me up, and cause arguments.

 

[SPECIAL LOCATION]

I'm not certain whether Ian's misunderstanding is genuine?It would appear from other posts on this thread and other threads that he is deliberately attempting to wind me up, and cause arguments.

I am struggling with a crossword anagram...

(Kettle, Pot, Black, Calling, The)

:|

Possible suggestions anyone?

:coat

put the kettle on

 

[spinlondon]

Sorry Specs did you say something?

I'm supprised you haven't looked into this thread:

http://www.talk.electricianforum.co.uk/showthread.php?t=8474