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Topic Title: Power NI act of God?
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Created On: 07 February 2013 06:01 PM
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 07 February 2013 06:01 PM
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JWElect

Posts: 123
Joined: 11 June 2008

Hi all, been a long time since I posted here but think this worthy of a discussion. On Tuesday this week got a phone call from a plumber I know who said that a heating time clock he had recently replaced on a job had stopped working and had a burning smell coming from it. I asked him about the wiring and if it had been altered etc but it had just been a swap out a few weeks previously for the same brand/ model, so the back plate was unchanged and the wiring untouched. He thought it strange that 2 had gone faulty in a short space of time so I went around to take a look at it.

Half an hour later, arrive at job and as soon as I open the door I am greeted by the smell of burning plastic/ electronic components.. I was informed that the TV had just done the same thing as the time clock. My first thought was power surge so checked the power coming into the house. (It is a single phase TT system) I was shocked to find that between live - neutral it was reading 408V, Live - Earth 230V and Neutral - Earth 230. What we had was 2 separate phases of a 3 phase supply coming down the live and neutral... I immediately isolated the the incoming power and contacted the DNO (Power NI, formerly NIE). Got speaking to an engineer who informed me that there was a line down in the area (hit by a tree) and that someone was on call restoring it and would call out to the property next.
I left it at that, safely isolated and went to my next job. The occupants where quite concerned about there equipment but I explained they would need to take it up with power NI.
When the engineer arrived he corrected everything and they mentioned about the damage caused by this, he told them to contact the office as they should be eligible for a claim.
When they contacted the office they where told "sorry, This has been an act of God" so the insurance would not cover trees falling into the transformer and basically there was nothing they could do about it but buy themselves a new TV, timeclock and whatever else needed replaced.
Upon checking the local area it was quite obvious that no tree had fallen so they where contacted again and they changed their story to "it was a branch blowing into the transformer that caused the damage" and there was still nothing they could do about it.. As you can imagine the householder is pretty peeved about this.
Now my question is,. call me skeptical but surely a tree blowing into a transformer does not cause the neutral conductor to become a phase conductor without a BANG somewhere along they line.. My own opinion is that there has been a line down as they stated,.. but connected back up incorrectly,.. whats others opinions on this?
To me it seems like they`re trying to pull a fast one to cover their backs and someones error?

Any opinions welcome

Edited: 07 February 2013 at 10:31 PM by JWElect
 07 February 2013 06:52 PM
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jcm256

Posts: 1841
Joined: 01 April 2006

Yes, I once investigated an insurance claim, but it was for a low voltage outage, (Was claimed that a large motor had smoke poring from it after the lights had gone dim). Visited the DNO area office in person and they admitted a tree had taken down one high voltage line. Can't imagine the same situation that a neutral on the low voltage side of a transformer would go to phase voltage (grounded and all that). Ask for a written explanation from the DNO as to what caused this fault. In my case did they pay, they would have, but sometimes with insurance claims, they only wanted from me a report if it was genuine, then the Broker or Insurance company would just pay up themselves. In any case never mentioned the motor starter under voltage should have protected the motor. Mind you in another case have seen the result of jointer putting two phases into a number of dwellings, result something like what you described happened.
Not much help, but put pressure to find out the truth.

Regards
jcm
 07 February 2013 08:23 PM
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AJJewsbury

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My first thought was power surge so checked the power coming into the house. (It is a single phase TT system) I was shocked to find that between live - neutral it was reading 408V, Live - Earth 230V and Neutral - Earth 230. What we had was 2 separate phases of a 3 phase supply coming down the live and neutral... I immediately isolated the the incoming power

Now my question is,. call me skeptical but surely a tree blowing into a transformer does not cause the neutral conductor to become a phase conductor without a BANG somewhere along they line..


Could it just have been a simple broken supply N? A large load else where on the LV network connected between another phase and N on the customer's side of the break could then drag N up to close to that line's voltage.

(BTW if you can make your picture smaller, it'd make reading your text a lot easier!)

- Andy.
 07 February 2013 08:34 PM
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Parsley

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Supplier Lost neutral and neighbour on different phase, neutral floating hence 230v to earth and 400v l to n.

Regards
 07 February 2013 08:47 PM
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slittle

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That's the problem with open wire LV overheads that hopefully ABC will help solve. The neutral is normally the lowest in the run and often the first to get pulled down. I've seen it do exactly the same when a hedge cutter got hold of an pole earth which was crimped to the neutral. Pulled the neutral down and the installations down stream were, um............ smoking !

Stu
 07 February 2013 10:30 PM
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JWElect

Posts: 123
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Yeah, thinking about this the broken neutral and the load from the neighbours on a different phase sounds likely.. still think they should at least be entitled to some compensation for the damage to their equipment. Suppose thats something the occupier will have to sort out themselves.
 08 February 2013 09:21 AM
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AJJewsbury

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Might be worth the householder talking to their own insurers - they'll be keen to pass the costs on to the DNO if they can and will probably have had experience of the details of doing so already.
- Andy.
 08 February 2013 09:43 AM
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jcm256

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Just goes to show that in cases like this the TT system RCD's offered no protection, even if the over voltage fault caused a class 1 appliance or class 1 fixed equipment to short to earth and trip the RCD, it would be to late.
 08 February 2013 11:07 AM
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ArthurHall

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The DNO has an obligation to maintain their plant in a safe condition, this includes cutting back trees in close proximity to high voltage lines.
 08 February 2013 11:13 AM
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slittle

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Never mind the RCD's in TT systems, think about what happens with TNCS when it happens. Equipotential zones sudden become quite handy


Stu
 08 February 2013 11:37 AM
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Parsley

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You wouldn't want to be in the garden touching the outside tap thats not got an insulating insert fitted would you.

Regards
 08 February 2013 03:48 PM
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ebee

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Ring the DNO tell them you are an atheist therefore acts of god do not apply to you, therefore they must pay out.

sorted

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

Knotted cables cause Lumpy Lektrik
 08 February 2013 06:34 PM
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JonSteward

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A branch failing off a tree is not an 'act of god'
It's foreseeable and shows lack of maintenance by the DNO
IMO
The sunami that hit Japan in 2011 is an 'act of god'
Make a claim, slack maintenance is no excuse.
 08 February 2013 11:25 PM
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simongallagher

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NIE is still NIE, Power NI is the old NIE supply business, it was retained by the owner as a stand alone supply business when ESB bought the DNO part of NIE.
 08 February 2013 11:29 PM
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alancapon

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Originally posted by: JonSteward
A branch failing off a tree is not an 'act of god'

It's foreseeable and shows lack of maintenance by the DNO . . .

or the owner of the tree!

Regards,

Alan.
 09 February 2013 06:29 AM
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ebee

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Right then, "Own up, who owns this tree?"

Is it a DNO tree or a Non DNO tree? that is the question.

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

Knotted cables cause Lumpy Lektrik
 09 February 2013 10:23 AM
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JonSteward

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Originally posted by: alancapon

Originally posted by: JonSteward

A branch failing off a tree is not an 'act of god'



It's foreseeable and shows lack of maintenance by the DNO . . .


or the owner of the tree!

OK. Good point. I can't spell sunami either!
God could be the owner as he grows these things.
He also, makes the earth tectonic plates move too.
Blame God it's all his fault. Not sure of the address to post a claim.

Regards,



Alan.
 10 February 2013 09:19 AM
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AJJewsbury

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A branch failing off a tree is not an 'act of god'
It's foreseeable and shows lack of maintenance

I've a feeling it's not as simple as that. I know someone who was worried about the trees on neighbouring land dropping large branches which overhung her house. Despite several letters & the professional opinion of a local tree surgeon, the landowner did nothing. Later a large branch came down and completely wrote off her conservatory (very luckily no-one was hurt). A claim was made against the owner of the tree, but their solicitor simply pointed out that the weather reports at the time recorded high (gale-force?) winds and so claimed it was a result of the weather, rather than a fault of the tree. The householder's insurance apparently accepted that without question. So it seems that foreseeable doesn't equate to liability.
- Andy.
 10 February 2013 09:03 PM
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JonSteward

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Originally posted by: AJJewsbury


rather than a fault of the tree. - Andy.


A tree can't be at fault, it does what it does, fault is with owner not wind or branch.
I would have pushed that point.
 11 February 2013 12:54 PM
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AJJewsbury

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A tree can't be at fault, it does what it does, fault is with owner not wind or branch.
I would have pushed that point.

I think the logic was that if the trees were known to be unsafe (e.g. weakened by disease/rot) and the branch came down because of that then the tree's owner would be liable as they'd failed to take reasonable action to keep the tree safe. But it seems that if the tree was healthy then the owner wasn't under any obligation to do anything to it. The underlying attitude of the law seems to be that the owner can't be held liable just for owning a tree - they need to be negligent in some way. The logic that you or I might apply that any tree, even a perfectly healthy one, will come down given a high enough wind, doesn't seem to make the owner liable - it seems it's the wind's fault, not the tree's.

In the case I mentioned, although the tree was thought to be diseased, because of the high wind it might be expected that even a healthy tree might loose a branch, hence it couldn't be shown that the damage was the result of the disease rather than the wind.

It would be interesting if anyone did know the law's principles on this point (rather than just my second hand accounts).

- Andy.
IET » Wiring and the regulations » Power NI act of God?

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