Sudden bright lights - overvoltage/spikes? What to do?

[hsabbers]

Hello,

Lived in a new house now for 6 weeks and all has seems fine. However, yesterday evening a standing lamp plugged into a standard mains socket suddenly – albeit momentarily – became extremely bright, making both me and my partner jump. It happened a couple more times and, as it was quite late, we basically shut down most things and went to bed.

Well, today it seems to be continuing. A lamp plugged into another socket – upstairs, but I think on the same circuit – did the same thing. There’s no particular frequency to these occurrences but it’s probably happened about 7 or 8 times now. An overhead lamp, which I assume is on a different circuit seemed unaffected.

What could be causing this overvoltage/spiking on the sockets? Should I be worried? It's a pretty new house - built in 1999 - on a large new-build estate so all the electrics should be modern and consistent.

Any ideas?

Harry.

 

[cumbriahandyman]

Are neighbours having the same problem?

 

[bernardgreen]

This could be a fault in the local areas supply network.

Contact the district network operator as matter of urgency ( they have an emergency number ) and tell them you appear to be getting over voltage supplies.

 

[hsabbers]

Are neighbours having the same problem?

Neighbours on both sides out right now but obviously we intend to ask them as soon as they return.

Harry.

 

[EngStudent]

Are neighbours having the same problem?

Neighbours on both sides out right now but obviously we intend to ask them as soon as they return.

Harry.

You'll need to try more than just those neighbours as they're possibly (probably) on a different phase to you. Try next door but one, two etc.

 

[holmslaw]

..

 

[bernardgreen]

Ask them if they are getting dimmed lights as well as asking about brighter lights.

If they are then it is most likely a failed or failing neutral in the local network and that needs to be reported to the network operator as soon as possible as it can result in damage to electrical equipment in you home. In the case of PME supplies it can present a safety hazard as it can affect the earthing in the houses.

If this is happening at random during the day then I would immediately notify the network operator ( DNO ) , That is NOT the company you pay your bills to but the company that installs the supply cables in the area. If you cannot find the DNO's phone number then your billing company must give you the number.

 

[hsabbers]

Certainly a network fault you should urgently report to your dno, you can find them here http://www.nationalgrid.com/uk/Electricity/AboutElectricity/DistributionCompanies/[/QUOTE]

Thanks - have now reported to DNO and they are indeed sending out an engineer in the next 24 hours. Anything sensible we should be doing in the meantime?

 

[holmslaw]

..

 

[hsabbers]

If they are then it is most likely a failed or failing neutral in the local network and that needs to be reported to the network operator as soon as possible as it can result in damage to electrical equipment in you home. In the case of PME supplies it can present a safety hazard as it can affect the earthing in the houses.

What are PME supplies? And in what way may the earthing in my house be affected?!

Harry

 

[ban-all-sheds]

Certainly a network fault you should urgently report to your dno

It's not affecting all the circuits in the house. In fact, the info we have is that it could well be only one circuit affected.

Maybe there's a loose connection for that circuit, and that when the light goes bright that's how bright it should be.

 

[bernardgreen]

What are PME supplies? And in what way may the earthing in my house be affected?!

PME supplies have an "earth" provided by the supply company which is derived from ( i.e. connected to ) the neutral where the supply cable enters the main company fuse box. As the neutral is earthed by the supply company this is a reasonable good and safe way to produce a "good" earth for safety of electrics inside the house. But when the neutral in the supply network has a fault then the "earth" supplied to the house is no longer the same as the ground outside the house.

It is still safe inside the house as everything that might present a hazard is equipotentially bonded to the "earth" meaning there are no dangerous voltage differences between things that can be touched. Though the voltage supploed to lamps and appliances may be too low for them to work or so high it damages them.

The hazard from a damaged network neutral is when something or someone touches the indoor "earth" and the outdoor ground which may be several or many volts different from each other.

Hence the need to report as soon as possible..

 

[cumbriahandyman]

It's not affecting all the circuits in the house.

How do you know that, sounds to me like it has only been noticed in the lighting so far.

Protective multiple earthing (PME) is a way of providing a safety earth through the electricity distribution network.

 

[rebuke]

It is still safe inside the house as everything that might present a hazard is equipotentially bonded to the "earth" meaning there are no dangerous voltage differences between things that can be touched. Though the voltage supploed to lamps and appliances may be too low for them to work or so high it damages them.

While (assuming that MEB is in place etc) there shouldn't exist a potential difference between things the householder can touch, surely there is still a risk, as you are in some amount of contact with true 'earth' by the fact you're standing on it (in particular imagine using a metal outside tap?)

Also, you've got the potential issue where if you have a relatively 'good' connection to ground via your pipework or say an old earth rod then you may end up sinking a lot of the current for other customers through said connection, which may be more current than it was designed to leading to cables melting etc...

 

[hsabbers]

It's not affecting all the circuits in the house.

How do you know that, sounds to me like it has only been noticed in the lighting so far.

Protective multiple earthing (PME) is a way of providing a safety earth through the electricity distribution network.

Well, the trouble here, of course, is in the randomness of these spikes - I just don't know when they're coming and, of the ones that have happened, I have to work from memory, obviously. So, we have one standing lamp and one bedside lamp connected to sockets on the SAME circuit -- BOTH of these have exhibited the sudden brightness.

However, as a control, we have also switched on an overhead filament light that is attached to a DIFFERENT circuit. So far, this doesn't seem to have exhibited the sudden brightness problem. It *was* on last night when the problem first started but, as all our attention was drawn by the nearer standing lamp (on the socket circuit), I can't say for certain whether or not the overhead filament light on the lighting circuit brightened at the same time. My *belief* is that it DIDN'T. But I can't be certain.

The trouble is, the spikes now haven't happened for a few hours, since we turned on the overhead light and the socket light - so it's hard to say whether both are affected.

Sigh.

Still waiting on the DNO engineer...