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Topic Title: DNO & problem with TN-S
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Created On: 30 April 2013 06:48 PM
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 30 April 2013 06:48 PM
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MBA

Posts: 68
Joined: 05 March 2006

Hi All

I am currently working in a terraced house in central London with TN-S supply. The Ze reading was high (3.5 ohms) so I rang up DNO (Uk Power Notworks) who came the following day to check and confirmed the high reading but to my surprise they said it is nothing to do with them. This is their response:

" EFLI value is unsatisfactory and no earth is provided or the earth is provided using an unapproved connection. You are advised to either Provide an independent local earth with RCD protection or Request a new PME service."

If this was a TT system then what they say makes sense but it is clearly a TN-S system with the cable sheath visible around the incoming cable.
Is it not DNO's responsibility to put this right and provide earth connection to the sheath of the cable?

Thank you
Martin
 30 April 2013 07:00 PM
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alancapon

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Not necessarily. It could be a TT service provided on a PILC cable.

Regards,

Alan.
 30 April 2013 07:27 PM
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OMS

Posts: 19592
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Originally posted by: alancapon

Not necessarily. It could be a TT service provided on a PILC cable.

Regards,

Alan.


In central london Alan ?

Sounds like UKPN spinning a line to shift the responsibility to the electrician or to put in place a charge for PME when they should be repairing under thier obligation at no cost to the client.

Not all DNO's are created equal in my experience

Regards

OMS

-------------------------
Failure is always an option
 30 April 2013 07:45 PM
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MBA

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Alan - If it is a TT then I would expect to see a 200mA RCD on the main incomer, but there isn't one. And I can see the actual cable under the floor boards going out of the boundary of the property to the pavement outside. So there isn't any earth wire attached to the PILC cable within the property.

OMS - I share the same view as you that UKPN is trying to rob my client of £2 - £3 K in rectifying their own fault!

Martin
 30 April 2013 09:06 PM
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mikejumper

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Any chance of getting into an adjacent property to see what arrangements they have?
 30 April 2013 10:19 PM
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SKElectrical

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Originally posted by: mikejumper

Any chance of getting into an adjacent property to see what arrangements they have?


That's what I do.

Can you just tap off neutral. What is wrong with that method? (I've never tried this)
 30 April 2013 10:26 PM
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UKPN

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"cant you just tap off the neutral"

dear oh dear.

Regards
 30 April 2013 10:30 PM
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John Peckham

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That is the standard response from UKPN assuming you can get a response from them in the first place. As for the bit about unapproved connections if they are referring to BS951 clamps on the lead sheath they were fitted in their thousands by the LEB, EDF and their contractors. If they provided the earth in the first place then they have a statutory duty to maintain it. That may be hard to prove but a complaint to OFGEM and/or the HSE may get them to maintain their network. It is probably the joint where the cable goes in to the joint box where there is a wooden bung that has rotted away over the years and the water is getting in.

Is there a clamp on the lead sheath? If not they are not under any obligation to supply an earth.

-------------------------
John Peckham

http://www.astutetechnicalservices.co.uk/
 30 April 2013 10:49 PM
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UKPN

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"assuming you can get a response from them in the first place"

clearly you are dialing the wrong number, UKPN give a breathtakingly
quick response to all calls, even with the ever increasing no of queries
which amateur "electricians" need an answer to.

Regards.
 30 April 2013 10:57 PM
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ebee

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Did someone say "Pigs fuelled and ready to fly"?

-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 30 April 2013 11:38 PM
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SKElectrical

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Originally posted by: UKPN

"cant you just tap off the neutral"

dear oh dear.


-Chuckle!!
I wasn't serious. That said, if DNO deems the supply cable is up to the job...
 30 April 2013 11:49 PM
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peteTLM

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Originally posted by: UKPN

"assuming you can get a response from them in the first place"



clearly you are dialing the wrong number, UKPN give a breathtakingly

quick response to all calls, even with the ever increasing no of queries

which amateur "electricians" need an answer to.



Regards.


Valid queries from people wanting to know what type of supply they have most presumably.
Unfortunatly ukpn dont know the answer either, and have a convinient case of ammnesia where everything becomes TT (not us guv)

-------------------------
----------------------------------------
Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry
 30 April 2013 11:56 PM
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MBA

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Thank you for all your comments.
Yes, there is a BS951 earth clamp on the lead sheath.
I'll be checking next door neighbour's arrangements and will come back on Monday.

Regards
Martin
 01 May 2013 12:29 AM
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SKElectrical

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If that's the case and DNO say they won't solder on an earth then you'll have to treat as TT. What a pain. I've never installed one, never tested one, never seen one.
In the past the supplier in this part of England has indeed connected to the supply neutral and then linked to sheath earth via soldered connection. I assume that it was TNS but the earth had degraded, so was then converted to TNC-S and then local sheath connected. Who knows - they're not the chattiest people.
 01 May 2013 09:26 AM
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OMS

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Originally posted by: UKPN

"assuming you can get a response from them in the first place"



clearly you are dialing the wrong number, UKPN give a breathtakingly

quick response to all calls, even with the ever increasing no of queries

which amateur "electricians" need an answer to.



Regards.


Meanwhile - back here on planet Earth, it's my experience that a frightningly large number of DNO personnel have no basic knowledge of thier systems and even less interest in them - being focussed on dealing with the increasing number of faults arising on ageing and badly maintained systems - reactive rather than preventative basically.

regards

OMS

-------------------------
Failure is always an option
 01 May 2013 10:05 AM
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BigRed

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Hepworth clamp time, but should be fitted by the REC, just threaten them with ofgem, ask to speak to a level 2 operative, the first line guys can't make that decision, you are wasting your time.
 01 May 2013 01:00 PM
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Zuiko

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MBA,

Sadly for the consumer, the adivce given by the DNO is correct.

Earthing arrangments are nothing to do with the supplier. They supply power, not an earth
 01 May 2013 02:05 PM
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OMS

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Originally posted by: Zuiko

MBA,

Sadly for the consumer, the adivce given by the DNO is correct.

Earthing arrangments are nothing to do with the supplier. They supply power, not an earth


Err - I don't think so - try reading ESQCR.

They have obligations to maintain neutral earthing (in all system types)and also to maintain consumers means of earthing where these have been provided.

regards

OMS

-------------------------
Failure is always an option
 01 May 2013 02:15 PM
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Zuiko

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The ESQCRs say that the supplier's neutral must be continuous, and that this neutral be earthed at the voltage source.

The DNO is not obligated to provide a customer with a means of earthing their installation.

If a consumer has a poor ELI, they can do one of the two things the DNO has suggested: use an RCD or ask for PME (which may or may not be available)

the original query was, "Is it not DNO's responsibility to put this right and provide earth connection to the sheath of the cable?"
The answer is absolutely not. The DNO has no respsonsibility for the earthing arrangment of the consumer. The DNO is required by ESQCR to provide a phase(s) within tolerance and to provide a continuous neutral that is earthed. They are not responsible to provide an earth connection as requested.

Edited: 01 May 2013 at 02:32 PM by Zuiko
 01 May 2013 02:32 PM
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OMS

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Originally posted by: Zuiko

The ESQCRs say that the supplier's neutral must be continuous, and that this neutral be earthed at the voltage source.



The DNO is not obligated to provide a customer with an "earth".


Reg 24

(4) Unless he can reasonably conclude that it is inappropriate for reasons of safety, a distributor shall, when providing a new connection at low voltage, make available his supply neutral conductor or, if appropriate, the protective conductor of his network for connection to the protective conductor of the consumer's installation.


Seems pretty clear that he does have that obligation.

And having provided it, then clearly the regs also place a duty on him to maintain it ?

Regards

OMS

-------------------------
Failure is always an option
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