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Topic Title: Earthing Options
Topic Summary: Where is it?
Created On: 02 April 2013 02:40 PM
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 02 April 2013 02:40 PM
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DR2366

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Pics

New customers installation but it would appear to be either using the incomming services for a means of earthing or TT (can't see an electriode).

What options are there for getting it swapped to either a TNS or PME supply?

The nature of the proposed works means a rewire so the cloth tails and the meter certified in 1988 needs attention anyway.

Thanks
 02 April 2013 03:15 PM
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weirdbeard

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Before going into earthing it might be worth considering getting the lot moved outside if poss - see jcms recent post about cutout fires and court action!

http://www.theiet.org/forums/f...tid=205&threadid=51769
 02 April 2013 03:23 PM
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DR2366

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Wouldn't that be the decision of the customer or DNO?

My reasons to request this would be to reduce the risk of fire to the property I presume?
 02 April 2013 03:34 PM
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OMS

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Ring the clients DNO and tell them that you have a a metal-clad Isco link box with what you think is a fused neutral present - and it's been smoking a bit (apply a candle flame locally to leave a bit of "heat" damage visible)

ask them to swap out the head and drop you a TN - S or TN-C-S earthing terminal whilst they are about it

Better still get the client to ring based on your script.

regards

OMS

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 02 April 2013 04:23 PM
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AJJewsbury

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Where is it?

In an installation of that age, it was probably the incoming (lead?) water pipe.

- Andy.
 02 April 2013 07:12 PM
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DR2366

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That will be the one with the nice plastic water meter in then!
 02 April 2013 07:30 PM
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weirdbeard

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Originally posted by: DR2366

Wouldn't that be the decision of the customer or DNO?



Well the customer wouldn't know, and the DNO are unlikely to volunteer that kind of info!
 02 April 2013 09:52 PM
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primo

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Originally posted by: OMS

Ring the clients DNO and tell them that you have a a metal-clad Isco link box with what you think is a fused neutral present - and it's been smoking a bit (apply a candle flame locally to leave a bit of "heat" damage visible)



ask them to swap out the head and drop you a TN - S or TN-C-S earthing terminal whilst they are about it



Better still get the client to ring based on your script.



regards



OMS


I tried that last week, although didn't apply the candle flame (good idea though!) and was told to bang a rod in. BS951 on the lead so told by the emergency call out guy that the jointers would just walk away if they saw it (even though it looks official not DIY). Metal cut out noted and "hopefully" will be replaced in the next two or three months.

However, did the same last year (and neutral fuse had blown in the cut out which surprised the builders stripping out!) and promptly got a nice new series 7 and new sweated earth to the lead.

You win some you loose some.
 02 April 2013 11:35 PM
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alancapon

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Originally posted by: DR2366
New customers installation but it would appear to be either using the incomming services for a means of earthing or TT (can't see an electriode). . .

It looks like an old TT supply to me, but you will need to get the DNO to confirm the earthing type.

. . . What options are there for getting it swapped to either a TNS or PME supply? . . .

Again, the DNO will have to confirm what is available. We are not familiar with the construction and earthing of the LV network in the vicinity of the property.

. . . The nature of the proposed works means a rewire so the cloth tails and the meter certified in 1988 needs attention anyway. . .

I agree with the cloth covered tails, but that make of Ferraris disk meter with a certification date of 1988 is not a great worry.

Regards,

Alan.
 02 April 2013 11:41 PM
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alancapon

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Originally posted by: weirdbeard
Before going into earthing it might be worth considering getting the lot moved outside if poss - see jcms recent post about cutout fires and court action! . . .

That court report needs to be taken in context. In terms of the number of installed cutouts and the number of fires at the meter position that are attributable to a cutout, especially one that is correctly sealed by the supplier and not intefered with are minimal. It also needs to be remembered that in the class action, the case against the various DNOs was not proved.

Regards,

Alan.
 03 April 2013 11:21 AM
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rocknroll

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I have to support Alan is most areas, the majority of fires that originate from the cut out area are a result of overloading, electrical theft and illegal interference and modification by contractors.

Infrastructure protection and security of supply and revenue is a big issue for us at the moment, we are examining new technology and one of them is a hermetically sealed cut-out with an auto resettable device on board and possibly digitally linked to the smart-meter, meter operators and the DNO's have been tasked with recording missing seals and recording when new seals have been fitted for evidentiary purposes, the revenue act is to be modified later in the year or next with ideas like missing seals could subject the householder to pay an average of five years billing or a fixed penalty of £3k.

I find it quite troublesome that most of you are so concerned about the DNO's equipment, probably because it is a taboo area where you should not be playing or you dream of working for them, its a pity you dont put so much effort into looking after your client.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
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"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------
 03 April 2013 11:41 AM
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AJJewsbury

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I find it quite troublesome that most of you are so concerned about the DNO's equipment, probably because it is a taboo area where you should not be playing

Unfortunately the IET seem to think we should be examining the supplier's equipment - just look at the new model EICR (section 1.0)
- Andy.
 03 April 2013 12:28 PM
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weirdbeard

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Link with some fire damage pics in section 9

http://www.cfoa.org.uk/download/18650

Certainly worth considering a move if the opportunity arises ie when getting the DNO involved and rewiring?
 03 April 2013 12:57 PM
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alancapon

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If the customer wants the supplier's equipment moved to a more convenient place that also fits the supplier's requirements for siting, then I am sure that can be accomodated at the clients cost.

Again, I repeat, there is no evidence that supplier's equipment located inside a property is a fire risk as long as it is correctly sealed by the supplier / DNO and has not been intefered with by others. As rocknroll says, there are a number of possibilities for guarding the cutout a bit more than a lead seal. All of these are currently allowed by the ESQCR - even a padlocked box is acceptable in the regulations. The wholesale installation of smart metering will also help, as it will be fairly easy to determine whether a "supply fail" alarm was the result of a failure of the supplier's network or the unauthorised withdrawal of a cutout fuse. There is also the option of auxiliary connections to detect the removal of certain covers on the supplier's equipment.


Regards,

Alan.
 03 April 2013 01:01 PM
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alancapon

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Unfortunately the IET seem to think we should be examining the supplier's equipment - just look at the new model EICR (section 1.0)

Yes, for some strange reason that has appeared on the form. What is missing, is any standards that you can use to assess it with, making the inclusion almost useless in my opinion. BS7671 only begins at the outgoing (load) terminals of the meter, or at the outgoing (load) terminals of the islolator switch, where this has been installed by the supplier / meter operator.

Regards,

Alan.
 03 April 2013 01:30 PM
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AJJewsbury

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I agree Alan. I know there was some debate in the GN 3 meetings - the general consensus was that inspections (& test) should contain themselves to the scope of BS 7671 - and on that basis a whole raft of checks in GN 3 based on building regs (not just P, but A, B and M too) were dropped. When the question of supplier's equipment on the EICR was raised it was basically concluded that as that's what's in BS 7671, that's what we (GN 3) have to work with, like it or not. Then to top it all the NICEIC want us to check whether the water cistern supplying an immersion heater is plastic or metal. All done with the best of intentions I'm sure, but muddled none the less.

- Andy.
 03 April 2013 01:35 PM
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AJJewsbury

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Originally posted by: weirdbeard

Link with some fire damage pics in section 9



http://www.cfoa.org.uk/download/18650




Thanks weirdbeard - very interesting.

I notice that in many cases one screw of the double-screw terminals seemed to have either not been tightened at all or missed the conductor.

Also all the instances seemed to be on L, rather than N - so presumably the heat from the fuse is having a small but significant detrimental effect - otherwise we'd expect to see similar problems on N - especially on single phase installations.


- Andy.
 03 April 2013 03:58 PM
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rogersmith7671

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It might be best to limit the extent of any condition reports you might carry out. In order to protect yourself if, any subsequent attempt to impose a duty of care upon you, where to be made in a court. In respect of faulty supply equipment.
The fires in almost all cases (in the fire investigating officers reports) were found to have originated in the suppliers equipment, it is possible to fool some of the people some of the time, but it's difficult to fool a fireman when they have to enter burning buildings and risk death.
The reason why the claim against DNO's failed was because any duty of care the DNO's had to effectively monitor, during meter reading and/or scheduled inspection, was not proved to the extent the court required and among other reasons, the DNO's have an effective contractual limitation, in that a domestic customer is not entitled to any redress in the event the cause is beyond their reasonable control or not foreseeable.
There is no doubt that numerous and serious fires originate from supply company equipment. The question is "who's responsible?"
Well as referred to in the summing up, a Public Inquiry may have called for different evidence(intimating that such a tribunal might have come to a different conclusion than his court).
If the conclusions in the Fire Investigation Officer's report together with the numbers involved where to be extrapolated to the rest of the UK then some sort of proper look into these matters is urgently required.

Regards
 03 April 2013 04:22 PM
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weirdbeard

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Originally posted by: alancapon


Again, I repeat, there is no evidence that supplier's equipment located inside a property is a fire risk as long as it is correctly sealed by the supplier / DNO and has not been intefered with by others.


Hi Alan, I think the evidence given in the link speaks for itself and is only data from one of the 63 FRS's throughout the nation - it goes onto say that there is a 1 in 30,000 chance per year that a fire incident causing the attendance of the FRS will occur due to a ' electrical before the meter' problem - there's no mention of any interference by others increasing the risk, or that the cutouts being sealed reduce the risk.

I'm not sure in the grand scheme of things whether 1 in 30000 is considered a great risk, but based on looking into this, if there is an opportunity to for a rewire customer to have their intake equipment updated and relocated from under the wooden stairs to an external position then it's certainly worth looking into.
 03 April 2013 05:18 PM
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weirdbeard

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Originally posted by: rocknroll

I have to support Alan is most areas, the majority of fires that originate from the cut out area are a result of overloading, electrical theft and illegal interference and modification by contractors.


Overloading??? do DNO's have special fuses that don't do overloads?
IET » Wiring and the regulations » Earthing Options

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