Appliances in single phase property damaged by 415v

[I Trippet]

Got an emergency call out from a very worried old lady the other night - the power at her apartment had gone off and the kitchen light was smouldering badly. She'd been on the phone to the DNO (Northern Powergrid), they were telling her to turn the main switch off but she couldn't understand and was frightened. As soon as I walked in I could smell the smouldering, although it had stopped by then as lighting circuit breaker had tripped. The light was an old fluorescent batten with a bulky transformer - it was hot and could tell it was burnt out. At first I thought it must have just failed itself and the MCB has done it's job. Alarm bells started ringing though when she said her tv and table lamp flickered for a short while before going off.

I turned the main switch off at the consumer unit and measured the supply voltage - 415v between line and neutral, 240v between neutral and earth! I said I'd contact Northern Powergrid and there was nothing more I could do for now but reassured her the power was isolated. I was puzzled because the stairwell lights were fine and I could see lights on in other apartments. The next morning, I phoned her as NPG wanted confirmation she would be in for the next three hours. Apparently the other two apartments on that side of the building, directly below hers, also had no power but they had gone to bed so didn't realise until the morning. She phoned me back later to say someone had been to her apartment, checked the supply in the meter cabinet and told her it was fine.

I went back later to put power back on for her, check everything was safe inside and replace the kitchen light. I checked the supply voltage, hey presto 240v line to neutral, 0v neutral to earth. Turned the power on again, numerous light bulbs had blown, a radio, a radio alarm clock and her tv aren't working, the fuses were all fine. Out of curiosity I unscrewed the cover for the radio alarm clock and sure enough several components had blown/melted.

My concern is how little information the engineer from NPG gave about any fault on their network that had now been sorted, just told her it was fine. Well, I wasn't imagining the reading on my tester the night before and several appliances have been damaged that were working. I'm wondering how likely it is that the fault is intermittent and wasn't showing at the time the engineer came - he checked it, said it was fine and cleared off. Or is it possible they are keeping quiet about what had caused it in the hope she won't make any claim off them for any damage?

 

[snowhead]

Sounds like loss of DNO Neutral at a point (D.B ?) common to the 3 (or possibly more) appartments.
It may be an issue within the building network / distribution so not the problem of NPG.
The fault will return if no-one has fixed it.

 

[i=p/u]

He could.of fixed it.and not said.

 

[I Trippet]

Sounds like loss of DNO Neutral at a point (D.B ?) common to the 3 (or possibly more) appartments.
It may be an issue within the building network / distribution so not the problem of NPG.
The fault will return if no-one has fixed it.

That's what I'm thinking. I looked and looked all over the building, couldn't find any service room, all locked doors were just storage cupboards. There is actually a substation on the driveway to the apartments and I suspect they are fed directly from that rather than via a main supply to the whole building, but could be wrong. Phoned people responsible for maintaining the building but they were clueless.

 

[I Trippet]

He could.of fixed it.and not said.

I hope so but would have thought he'd made some comment as to what had happened or acknowledged the fault.

 

[i=p/u]

Less said the better maybe.

 

[UNG]

Got an emergency call out from a very worried old lady the other night - the power at her apartment had gone off and the kitchen light was smouldering badly. She'd been on the phone to the DNO (Northern Powergrid), they were telling her to turn the main switch off but she couldn't understand and was frightened. As soon as I walked in I could smell the smouldering, although it had stopped by then as lighting circuit breaker had tripped. The light was an old fluorescent batten with a bulky transformer - it was hot and could tell it was burnt out. At first I thought it must have just failed itself and the MCB has done it's job. Alarm bells started ringing though when she said her tv and table lamp flickered for a short while before going off.

I turned the main switch off at the consumer unit and measured the supply voltage - 415v between line and neutral, 240v between neutral and earth! I said I'd contact Northern Powergrid and there was nothing more I could do for now but reassured her the power was isolated. I was puzzled because the stairwell lights were fine and I could see lights on in other apartments. The next morning, I phoned her as NPG wanted confirmation she would be in for the next three hours. Apparently the other two apartments on that side of the building, directly below hers, also had no power but they had gone to bed so didn't realise until the morning. She phoned me back later to say someone had been to her apartment, checked the supply in the meter cabinet and told her it was fine.

I went back later to put power back on for her, check everything was safe inside and replace the kitchen light. I checked the supply voltage, hey presto 240v line to neutral, 0v neutral to earth. Turned the power on again, numerous light bulbs had blown, a radio, a radio alarm clock and her tv aren't working, the fuses were all fine. Out of curiosity I unscrewed the cover for the radio alarm clock and sure enough several components had blown/melted.

My concern is how little information the engineer from NPG gave about any fault on their network that had now been sorted, just told her it was fine. Well, I wasn't imagining the reading on my tester the night before and several appliances have been damaged that were working. I'm wondering how likely it is that the fault is intermittent and wasn't showing at the time the engineer came - he checked it, said it was fine and cleared off. Or is it possible they are keeping quiet about what had caused it in the hope she won't make any claim off them for any damage?

So if I'm reading this post correctly a vulnerable old lady was left without power overnight or certainly for several hours on her own, also the DNO only appears to have only responded to the fault call the following day. If this is correct then I feel there is a good reason to raise a complaint
As an electrician attending a property with the fault that is described I would expect on contacting the DNO that an emergency crew would be on site within 2 - 3 hours

I think for the more experienced it is very easy to understand why the DNO is not forthcoming with what the fault was as it would no doubt result in a potentially large compensation claim for the damaged equipment, a fault like this one does not fix itself and must have had some work done by the DNO to correct the problem

 

[snowhead]

I wouldn't be surprised if the other 2 appartments have got as yet undiscovered failed / faulty appliances.
Possibly even others beyond the 3.

They could all end up individually paying to have items fixed when they shouldn't be.

 

[UNG]

I wouldn't be surprised if the other 2 appartments have got as yet undiscovered failed / faulty appliances.
Possibly even others beyond the 3.

They could all end up individually paying to have items fixed when they shouldn't be.

This is where I feel you have to be a bit more forensic in how you go about your faultfinding and reporting of the issue IMO, knocking on neighbours doors and doing a quick check of their supply, taking a look outside at the street lighting and the other properties along the street usually gives a good indication of the extent of the problem and it all helps when you make that call to the DNO if you have some understanding of the distribution system to indicate where the fault may be. These days with cable theft it would not be that uncommon to find a substation has had it earth cabling removed causing the neutral point to float

 

[I Trippet]

So if I'm reading this post correctly a vulnerable old lady was left without power overnight or certainly for several hours on her own, also the DNO only appears to have only responded to the fault call the following day. If this is correct then I feel there is a good reason to raise a complaint
As an electrician attending a property with the fault that is described I would expect on contacting the DNO that an emergency crew would be on site within 2 - 3 hours

I think for the more experienced it is very easy to understand why the DNO is not forthcoming with what the fault was as it would no doubt result in a potentially large compensation claim for the damaged equipment, a fault like this one does not fix itself and must have had some work done by the DNO to correct the problem

Yes, she rang them first and they told her to isolate the supply and call an electrician. At that point it wasn't clear what had happened, they could have reasonably just thought it was a faulty light fitting and nothing to do with them. When I realised what the problem was I phoned back but said they wouldn't treat it as an emergency as long as the supply was isolated, and call again in the morning. So no, she had no power overnight which is bad, but she was just relieved to go to bed knowing the light wasn't going to carry on burning!

 

[I Trippet]

I wouldn't be surprised if the other 2 appartments have got as yet undiscovered failed / faulty appliances.
Possibly even others beyond the 3.

They could all end up individually paying to have items fixed when they shouldn't be.

I'm going back tomorrow I said drop off some more light bulbs for her and I'll try asking them. How likely is it to for them to successfully claim for damage from NPG?

 

[UNG]

Yes, she rang them first and they told her to isolate the supply and call an electrician. At that point it wasn't clear what had happened, they could have reasonably just thought it was a faulty light fitting and nothing to do with them. When I realised what the problem was I phoned back but said they wouldn't treat it as an emergency as long as the supply was isolated, and call again in the morning. So no, she had no power overnight which is bad, but she was just relieved to go to bed knowing the light wasn't going to carry on burning!

So what did you identify the problem as?
As to the DNO response I would have certainly got the name of the person you spoke to as leaving a vulnerable old lady without power overnight is an extremely calous action and worthy of some retraining, I think I would have been asking to speak to the duty supervisor

I'm going back tomorrow I said drop off some more light bulbs for her and I'll try asking them. How likely is it to for them to successfully claim for damage from NPG?

I assume when you say them you are only referring to your customer, I don't think they have any chance of a claim due to the way it was reported to the DNO and the response they gave it

 

[Dartlec]

It may well be worth getting her to speak to the neighbours. If 3 separate apartments have had damaged appliances - along with your test result that night, I would think they would find it hard to argue that it was nothing to do with them (assuming there isn't a BNO involved).

At the very least I would put something in writing to the DNO - from the customer ideally, but with your 'site report' included (Just a description of your actions, on business letter headed notepaper.)

I'm surprised that they thought an elderly lady would be fine without any power overnight - at the very least a complaint in writing will make someone look at the call logs, etc.

Not sure if her insurance company might be worth mentioning this to as well (assuming she has one and was going to claim( - they might well be interested if they can offset any of their claim onto the DNO.

 

[I Trippet]

So what did you identify the problem as?
As to the DNO response I would have certainly got the name of the person you spoke to as leaving a vulnerable old lady without power overnight is an extremely calous action and worthy of some retraining, I think I would have been asking to speak to the duty supervisor

I assume when you say them you are only referring to your customer, I don't think they have any chance of a claim due to the way it was reported to the DNO and the response they gave it

The supply voltage was too high. Yes I agree it was bad of them.

I meant anyone that's had equipment damaged. When I spoke to them I made it very clear that I was getting 415v at the supply.

 

[LastManOnline]

I wouldn't be surprised if the other 2 appartments have got as yet undiscovered failed / faulty appliances.
Possibly even others beyond the 3.

They could all end up individually paying to have items fixed when they shouldn't be.

Ironically I had just finished sending an invoice tonight to the DNO for an exact same situation. It was you Snowhead who replied to my (similar) query a, few weeks ago and you mentioned your son got compensated from DNO for damages he suffered.
I had no issues when I contacted them. They achknowledged liability and simply asked for a list of damages and bank details. I think it would be rare if there was no record somewhere of a power outage. In any case, from what I have read here there certainly appears to be sufficient circumstantial evidence

 

[UNG]

The supply voltage was too high. Yes I agree it was bad of them.

I meant anyone that's had equipment damaged. When I spoke to them I made it very clear that I was getting 415v at the supply.

Do you have any idea why the voltage would be so high?

 

[I Trippet]

Do you have any idea why the voltage would be so high?

Possible broken neutral, I couldn't investigate any further as it's the DNOs domain.

 

[UNG]

Possible broken neutral, I couldn't investigate any further as it's the DNOs domain.

It's quite clear from your responses that you were totally out of your depth with this fault and lack some very basic knowledge of the electricity distribution system and what causes faults like this to occur

 

[I Trippet]

It's quite clear from your responses that you were totally out of your depth with this fault and lack some very basic knowledge of the electricity distribution system and what causes faults like this to occur

So instead of getting personal, how about you tell us your theory!

Not quite sure how I can be "out of [my] depth" when the fault is on the supply side and acknowledged it's the DNO's responsibility and contacted them.

 

[LastManOnline]

It's quite clear from your responses that you were totally out of your depth with this fault and lack some very basic knowledge of the electricity distribution system and what causes faults like this to occur

Is that a windup? What more could he have done?