exporting earth again!!!

[Apache]

There is an allowance in the regs for exporting earths be they TT or TNCS.

Where?

Strictly is it possible to export TT? You could rod either end.

 

[kme]

And a missing rod connection is safe? There is an allowance in the regs for exporting earths be they TT or TNCS.

What reg would that be, then??

Curious, I am (yoda is back!!!)

 

[Tooold]

Sorry to be honest I cant be bothered, you find it. Yes you could rod either end but if all regs are met you can export a TT. If I have a garage 10 feet from the house I feel it is safet to export pme. Semi detatched houses detatched houses flats etc all within touching distance. This subject goes and goes, I'v looked at the other threads and I think its all been said much better than I can. If you dont want to export dont. I'll come along and spot the lonesome rod the gardner, tarmac layer, block paving layer and idiot has disconnected and export.

 

[kme]

Nobody said you can`t export TT. We`re only interested with TN-C-S. You`ve obviously decided to ignore the general concensus of safe working, and do it your way.

((BTW, if the connection is within a protective enclosure, as it should be, it isn`t likely to be disconnected.))

That`s fine, if you`re happy with it. But don`t give other ( in some cases unqualified) forum readers non-compliant information.

If I were to do as you suggested, and that job was one of the inspection sites for my assessment, I`d expect it to be failed; as I haven`t complied with 7671. We know it isn`t perfect, but it IS what we have to work with.

My opinion only. I`ll get me coat now.

 

[kme]

I understand what you are saying about this situation and TT and agree. However I am transporting the earth to domestic outbuildings, garages and the like, as I have seen too many rods not connected, for various reasons. If the earth is disconnected on PME systems nowt works as the neutral has also gone.

COOL. Does that mean EVERYTHING is at phase voltage? Yes?

How is that safe? Yes, you`ll know there`s a fault when nothing works.

You`ll know a damn site quicker when the exposed metalwork uses you as an earth path.

 

[ianmacd]

If the earth is disconnected on PME systems nowt works as the neutral has also gone.

Not necessarily, with main bonding acting as a neutral via your garden and your neighbours back up their bonding and to neutral albeit with a slightly higher resistance. Besides, with no neutral, all your earths will be at 230V .

Ian.

 

[Tooold]

I didnt say it was safe! At least you know you have a problem, when the rod is gone you dont. IEE and NIC allow earth to be exported so how is that non compliant?

If you check the other threads on this subject ther are members that do export

This is a forum for disscusson not for personal attacks.

 

[Evans Electric]

No PME in petrol filling stations , unless things have changed . Sometimes the incoming Ze was higher than the tanks in the ground.

 

[Evans Electric]

KME ? Now where have we heard that name before ???

 

[kme]

Cheeky fart Sandra.

Sorry Mr ooold, I wasn`t making a personal attack. I was trying to make the point that it is intriniscally unsafe to export a PME to a detached building; unless certain conditions exist.

My NICEIC inspector is not happy with an exported PME earth, as we had this discussion at my renewal meeting last year.

KME

 

[Tooold]

No probs KME, it had just started to sound like another forum I dont frequent much.

Strangley my NIC inspector of 2 years ago said the same as ELECSA chap, and the one last year said the same as your last one. I did also ring NIC helpline twice and got the same two different answers!

Maybe we'll all have to agree to disagree.

 

[green-hornet]

And a missing rod connection is safe? There is an allowance in the regs for exporting earths be they TT or TNCS.

Yes you are correct.

You must also bond any metal pipes (water/gas) any extrenuous metal all back to the met. Not locally.

So if you do the risk assesment and consider it safe then export all you want.

I would however say that as far as I am concerned PME is not the safest earthing arrangement by a long way.

I do prefer TT, however this earthing does mean regular inspections. As I am sure other methods do.

There should always be a log inside the inspection chamber for the rod, tape or mat so you know that regular checks are carried out.

One of the main problems with a PME is the fact that if your at the end of a long line of PME installations your at the bottom of the protection list, and all faults prior to your property are shared along a common cable.

With TT your on your own, protected often more safer than pme.

I have just installed two earth rods at a school I have rewired, both rods are connected to the met and interlinked via 16mm earth to each db.

Before the rewire this part of the school was connected to the main db which is pme.

I get a better earth reading in the rewired part and faster disconnection times than the old part which will now probably require a rewire :^O .

As Andy says cost over efficiency is the only reason for a pme.

Most rural areas are TT and every farm I have worked on is TT.

I think people get afraid of TT because of the 100mA rcd and additional protection and bonding.

Not very disimmilar to the new 17th edition really with the exception of the 100mA rcd.

Getting one of those from your local DI geared wholesaler is hard:|

 

[tom1]

sorry i cant read all the threds they are too quick so i may be repeting here.

i rang central networks they said export pme is fine just dont mess with there cut out, not totaly convinced with girle on phone so spoke to there enginer in the street he said its ok then i said about droping netrals on there end and he said loads of places have exported and thats how it was when he was a spark

 

[Apache]

sorry i cant read all the threds they are too quick so i may be repeting here.i rang central networks they said export pme is fine just dont mess with there cut out, not totaly convinced with girle on phone so spoke to there enginer in the street he said its ok then i said about droping netrals on there end and he said loads of places have exported and thats how it was when he was a spark

Lots of people used to have outside toilets.

Lighting circuits used to have no cpc - my gran had an iron that connected to a bayonet lampholder.

Do we thing things are ok because that's how they were done in the past?

 

[Riggy]

They should never have supplied a farm with PME in the first place........................

Sorry, just catching up. I do work on loads of farms, I can't think of one which DOESN'T have a pme supply - almost always overhead (I've seen other threads claiming that overhead pme is a no-no). I can think of loads with exported pme earths. Curiously none of them was littered with dead cows / sheep / farmers / vets / electricians.

 

[tom1]

Lots of people used to have outside toilets.Lighting circuits used to have no cpc - my gran had an iron that connected to a bayonet lampholder.

Do we thing things are ok because that's how they were done in the past?

i think the point he was makeing was that if they did drop a nutral then loads of people would be at risk, if there is any risk

 

[kme]

I`m not getting into this. Not again. I just can`t face it.

My therapist had to retire after the last "exported" issue, and I can`t afford another one.

I`ll just sit on the sidelines and watch, if that`s ok?

KME

 

[tom1]

dont blame u. i have read some previos threads on this export pme they can get nasty

 

[Apache]

dont blame u. i have read some previos threads on this export pme they can get nasty

Threads never get nasty on here!

KME - don't think there's any more to be said on the subject, myself.

 

[batty]

Just remember if you do export a pme earth and things go wrong it will be your fault and you will be liable. If you read the suppliers literature its says you should not, I know this is mainly if there is services in the other building but I personally will not export a pme earth and usually not on tt or tns unless it is really awkward to get a rod in. Also you can get away with using twin armoured and use the steel as your cpc which on a long run can save a few quid. I think separate buildings should be kept separate from faults on the main building. This is the way I do it and will carry on that way.

Batty