Exporting the earth?

[Robo]

Im not 100% on earthing for submains. If the supply is tnc-s you are not ment to export the earthfrom db to say a detached garage?If i did export the earth could it not be classed as TNS instead?? Or to keep it TNCS run a seperate earth form cutout.Or just have the garage as a TT.

Are you aloud to export TNS from 1 db to another?

Or i could rod the garage and then it would be seperate?

 

[antimatter]

Under the Electricity safety, quality and continuity regulations 2002 you cannot use a suppliers earth to an out building, on a TNC-S Earthing arrangement, so the detached garage effectively becomes a TT installation with an earth electrode installed in the ground.

If you use SWA to supply the garage the armour must not be terminated at the garage end of the cable.

 

[tony mc]

Bit unsure re your TNCS to TNS

If you create a new earth at the garage that would have to be via a rod so it would be TT.

If you were to continue with a earth from the TNCS system it would remain that system and not change to TNS. Some DNO companys don't like you exporting it.


How far away is the detached garage and don't forget to bond in the garage.

 

[j.mawer]

http://www.electriciansforums.net/e...159-good-guide-exported-pme-outbuildings.html

 

[DurhamSparky]

if you have no Water or Gas in Garage just carry earth to the garage!!

if you are bonding i would SWA 2 Core and rod in garage!!

 

[Robo]

Bit unsure re your TNCS to TNS

If you create a new earth at the garage that would have to be via a rod so it would be TT.

If you were to continue with a earth from the TNCS system it would remain that system and not change to TNS. Some DNO companys don't like you exporting it.


How far away is the detached garage and don't forget to bond in the garage.

I dont actually have a job, im just enquiring for the future. Would it be ok to gland garage end and just not connect into earth bar, providing its insulated. If it was metal then use a stuffing gland and dont bother with armours.

 

[DurhamSparky]

always earth the armour!!!

 

[IQ Electrical]

Under the Electricity safety, quality and continuity regulations 2002 you cannot use a suppliers earth to an out building, on a TNC-S Earthing arrangement, so the detached garage effectively becomes a TT installation with an earth electrode installed in the ground.

If you use SWA to supply the garage the armour must not be terminated at the garage end of the cable.

That is absolutely incorrect, please read the Guide that I posted and Guidance Note 8.



This is the link to the thread: http://www.electriciansforums.net/e...159-good-guide-exported-pme-outbuildings.html

 

[tony mc]

If you are useing the earth from the TNC-S to protect the swa cable and then isolating it from the garage which now becomes TT.

I would use a insulated box so that both earths are kept seperate so you are only transporting the line conductors.

 

[Engineer54]

Seems the myths and mis-information on this topic continues... To my mind, Rods (TT) should always be considered as your last choice, not a first choice!!!

 

[Deleted member 9648]

Under the Electricity safety, quality and continuity regulations 2002 you cannot use a suppliers earth to an out building, on a TNC-S Earthing arrangement, so the detached garage effectively becomes a TT installation with an earth electrode installed in the ground.

If you use SWA to supply the garage the armour must not be terminated at the garage end of the cable.

God 'elp us.....what it it with outbuildings that promps otherwise competant electricians to spout complete nonsense?

 

[malcolmsanford]

The ESQCR replaced the old Electricty Supply Regulations 1988 in 2002. Us older members of the forum will remember that in the old Electricity Regulations there was a section concerning PME systems and it was if I remember correctly advised not to export an earth without the DNO permission. If I remember right it even advised that if you had an outside tap fed from the house it should be sheathed to protect against shock.

It as to be remembered that when these regulations were in force protection devices and installations were not as safe as they are now. The only installation in a domestic situation which had RCD protection, or then ELCB protection was a TT and so exporting earths were not as safe as they are now.

With todays modern protection, bonding and the majority of outside appliances being double insulated the exporting of an earth in a TNC-S system is not so dangerous. IMO I can see nothing wrong with it.

But old sparks are a die hard breed, I will still call the DNO and ask if they will let me export. Today I agree that the likely hood of an answer being "What are you asking for" is the one you will get. If the garage/outbuilding is perhaps a good distance from the house I would still most likely TT the building as that is what IMO is the way it should be.

I can't argue the fact that today even if the building is 40 metres from the house, it's not got services to it in metal, or is of a metal construction then why not export the earth, but as I'm one of those die hard old breed that is my opinion.

I'm would also like to add that I can't understand why there is such a downer in a TT installation. I'm not sure with todays protection devices why a system that as been in use for much longer than the other type of earth system is considered a last resort.

 

[DurhamSparky]

i prefere TT to any other installation!!

 

[antimatter]

God 'elp us.....what it it with outbuildings that promps otherwise competant electricians to spout complete nonsense?

Why do you disagree?

 

[antimatter]

http://www.electriciansforums.net/e...159-good-guide-exported-pme-outbuildings.html

Its 6 years old, Thats from 2005 / 16th edition.

 

[antimatter]

God 'elp us.....what it it with outbuildings that promps otherwise competant electricians to spout complete nonsense?

from j.mawers post.....

Where the installation in the garage is supplied by an armoured cable, the armour or any protective conductor in the cable must not be
connected to and must not be simultaneously-accessible with any exposed-conductive-parts in the outbuilding.

 

[j.mawer]

Not quite sure why the last post got a reference to me as the quote is from "Wiring matters" but it is also from the section regarding using TT system if the garage contains extraneous conductive part i.e. if you make the garage TT then don't connect it to the exported earth from the main building.

 

[antimatter]

@ j.mawer it was a ref to post number 4 (your link)

Just to confim the DNO do not allow exporting of PME

You must isolate the pme in an enclosure then TT the buildings instalation .

 

[IQ Electrical]

from j.mawers post.....

Where the installation in the garage is supplied by an armoured cable, the armour or any protective conductor in the cable must not be
connected to and must not be simultaneously-accessible with any exposed-conductive-parts in the outbuilding.

So you didn't read the paragraph below that regarding 'main protective bonding where PME conditions apply'?

The point is you have a CHOICE-often the only reason for selecting a TT system at the destination is economic reasons because of the way main protective bonding is sized for TN-C-S supplies.

You stated that ESQCR specifically forbids the methods that IET Guidance Notes 8 and 1 prescribe regarding using the suppliers earth to outbuildings on a TN-C-S supply.

Where is this in ESQCR because I am very familiar with it's content and the content of BS 7430 earthing & bonding and have no such reference in my copies of these documents!

 

[antimatter]

regulation 543.4.1 states that in Great Britain regulation 4 of the Electricity, Safety, Quality and Continuity Regulations 2002 prohibit the use of PEN conductors in the comsumers installation.

 

[IQ Electrical]

Not quite sure why the last post got a reference to me as the quote is from "Wiring matters" but it is also from the section regarding using TT system if the garage contains extraneous conductive part i.e. if you make the garage TT then don't connect it to the exported earth from the main building.

Exactly!

 

[IQ Electrical]

regulation 543.4.1 states that in great britain regulation 4 of the electricity, safety, quality and continuity regulations 2002 prohibit the use of pen conductors in the comsumers installation.

it's only a pen conductor up to the service head!!!!!!!!!!!!!!!!!!!!!!

Sheesh!!!!!!!

 

[antimatter]

@iq have you ever installed a submain to an outbuilding on a TNC-S earting system?

 

[IQ Electrical]

Of course I have, why are you having so much difficulty with this?

I have posted links to IET guidance, references to Guidance Notes 8 and 1 but you still can't comprehend it!

You don't understand what a PEN conductor is, and the fact that the S in TN-C-S is referring to the separation of the PEN conductor at the service head!

Please invest in the Guidance Notes if you want to understand these systems and the options open to you as an installer.

 

[antimatter]

Did you export the earth on the TNC-S system to the outbuiling?

 

[antimatter]

Of course I have, why are you having so much difficulty with this?

I have posted links to IET guidance, references to Guidance Notes 8 and 1 but you still can't comprehend it!

You don't understand what a PEN conductor is, and the fact that the S in TN-C-S is referring to the separation of the PEN conductor at the service head!


Please invest in the Guidance Notes if you want to understand these systems and the options open to you as an installer.

And I have have quoted ESQCR regs which prohibit exporting earth of TNC-S system, please read the literature available to you, this is electric basics.

 

[IQ Electrical]

And I have have quoted ESQCR regs which prohibit exporting earth of TNC-S system, please read the literature available to you, this is electric basics.

God you're right about the basics, this is killing me!

You quoted a reg regarding PEN conductors in consumers installations-please, before you post anything else, tell me what you understand by the term PEN conductor and how it is relevant to this thread.

Please just do that.

 

[antimatter]

Yes PEN ends at service head, good diversion you have made but the thread is about exporting the earth from a TNC-S system which you believe is plausible but the only proof you have is a publication from 2005 15th edition which uses the terms Direct and Indirect contact, hhhhhmnnnnnnn

 

[IQ Electrical]

Yes PEN ends at service head, good diversion you have made but the thread is about exporting the earth from a TNC-S system which you believe is plausible but the only proof you have is a publication from 2005 15th edition which uses the terms Direct and Indirect contact, hhhhhmnnnnnnn

Diversion? It's the reg that you misinterpret and base this wasted hour on!

I've posted IET meterial that has amended terminology but can you tell me what has changed in the transition to BS 7671:2008 with regard to the topic?

I've also asked you to read Guidance Note 8 and 1 where excellent diagrams are available to help you to understand this subject.

I enjoy a good debate but if you don't understand the topic yet continue to argue, it becomes very one-sided and tedious, please read the Guidance Notes, that is all it will take for you to take a step back and say 'oh, IQ was right all along, he has a grasp of these electrical basics'

Read the Guidance Notes

 

[antimatter]

Diversion? It's the reg that you misinterpret and base this wasted hour on!

I've posted IET meterial that has amended terminology but can you tell me what has changed in the transition to BS 7671:2008 with regard to the topic?

I've also asked you to read Guidance Note 8 and 1 where excellent diagrams are available to help you to understand this subject.

I enjoy a good debate but if you don't understand the topic yet continue to argue, it becomes very one-sided and tedious, please read the Guidance Notes, that is all it will take for you to take a step back and say 'oh, IQ was right all along, he has a grasp of these electrical basics'

Read the Guidance Notes

Why are you being so aggressive?

 

[antimatter]

we have different options and this is a forum for posting people opinions on and thats what we are doing.

 

[IQ Electrical]

we have different options and this is a forum for posting people opinions on and thats what we are doing.

The problem is, the IET guidance article and Guidance Notes 8 and 1 are not my opinion, they are IET publications.

Whereas you posted that 'ESQCR forbids exporting PME earth', again, implying that this was a fact, when it was actually you not understanding where a PEN conductor ends in an installation.

I don't think any forum members here would describe my posts as agressive, I just like the facts to be recorded ahead of anyones opinion, including my own.

 

[Deleted member 26818]

There is no prohibition in either BS7671 or ESQCR on exporting the earth in a TN-C-S installation.
The prohibition has always been fron the DNOs.
Their concern primarily is that installation earthing sytems will become the neutral path in the event of a supply neutral fault.

 

[antimatter]

There is no prohibition in either BS7671 or ESQCR on exporting the earth in a TN-C-S installation.
The prohibition has always been fron the DNOs.
Their concern primarily is that installation earthing sytems will become the neutral path in the event of a supply neutral fault.

Thats the way I understand it too.

 

[IQ Electrical]

There is no prohibition in either BS7671 or ESQCR on exporting the earth in a TN-C-S installation.
The prohibition has always been fron the DNOs.
Their concern primarily is that installation earthing sytems will become the neutral path in the event of a supply neutral fault.

Quite correct but is it also not true that the DNO's consider the chances of that type of fault occurring to be so small that they no longer impose terms other than on the obvious special locations?

 

[IQ Electrical]

Thats the way I understand it too.

What?

Your post that 'ESQCR forbids' started this whole thing!

Unbelievable, I must be going mad!!!!

 

[antimatter]

Think you need a chill pill mr iq

 

[IQ Electrical]

I chill knowing this thread will probably be read a few times....

 

[antimatter]

No work today?

 

[telectrix]

the following post is meant to be read in the spirit it is posted.

having been in the trade for a while, when the height of accuracy of resistance measurement was an AVO 7, with a bit of good eyesight you could just about get an accuracy of 1 and a bit ohms, not the zillionth of an ohm we read to now, a caclculator was a slip stickmade by thornton's who now make chocolate, and the only digital equipment was a red led watch, on some boffins drawing board, sketched in pencil, it was usual to TT outbuildings, as most installs were TT anyway . nowadays we have a choice. i only export the earth if the outbuilding has no extraneous metal conductive parts. the dangers inherent having been expained on this thread better than i can. so far nobody has been electrocuted on one of my installs, so i will continue as an old fossil until my legs give way, or goverment increase pensions to a level wherein i can live in the style to which i am accustomed.

 

[thekingiam]

ha ha i love this site!! so many "debates" going on and discusions talked about in a calm and adult manner without tempers being frayed !

 

[telectrix]

this is what sets this site above all others. there are occasional ruffled feathers, but on the whole a good forum. if anyone tries to get uppity, a verbal smack on the arse by a mod. soon puts things all smiles again.

 

[antimatter]

this is what sets this site above all others. there are occasional ruffled feathers, but on the whole a good forum. if anyone tries to get uppity, a verbal smack on the arse by a mod. soon puts things all smiles again.

Including the use of bad language

 

[IQ Electrical]

the following post is meant to be read in the spirit it is posted.

having been in the trade for a while, when the height of accuracy of resistance measurement was an AVO 7, with a bit of good eyesight you could just about get an accuracy of 1 and a bit ohms, not the zillionth of an ohm we read to now, a caclculator was a slip stickmade by thornton's who now make chocolate, and the only digital equipment was a red led watch, on some boffins drawing board, sketched in pencil, it was usual to TT outbuildings, as most installs were TT anyway . nowadays we have a choice. i only export the earth if the outbuilding has no extraneous metal conductive parts. the dangers inherent having been expained on this thread better than i can. so far nobody has been electrocuted on one of my installs, so i will continue as an old fossil until my legs give way, or goverment increase pensions to a level wherein i can live in the style to which i am accustomed.

The key point being that you know that you have a choice on the installation method.

 

[telectrix]

what bad language? that word is in the oxford english dictionary. i do agree that bad language is not recommended, and do not use such. anything
" bad" would automatically be starred.

 

[antimatter]

@telectrix

i was only joking

 

[telectrix]

The key point being that you know that you have a choice on the installation method.

exactly. beauty is in the eye of the installer.

 

[SimpleSimon]

The key point being that you know that you have a choice on the installation method.

I think that was a subpoint. The main point being is that he's old.

 

[IQ Electrical]

Perhaps best if I don't ask you to define 'old' Simon?

 

[SimpleSimon]

I'll just leave it on Im young enough to still take meaning on the saying "Respect your elders"