Author Topic: Constant High Mains Voltages At Home  (Read 19271 times)

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Offline paul_g_787Topic starter

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Constant High Mains Voltages At Home
« on: April 16, 2021, 05:51:30 pm »
Hi. I am wondering if someone can offer some insight into what might be causing this problem and what I can do to get it resolved.

I have been having problems with high mains supply voltage. It usually hangs out at 249-252V but at night, almost every night I can get 255V - 262V. I have also seen it go to 263V, 268V and 315V on three occasions.  :bullshit: :bullshit: :bullshit: When it went to 315V it blew up my UPS (APC BR1500GI) which now has an F02 output short. (Will look at fixing this later).

I have contacted my electricity supplier (British Gas) and they just hang up the phone or fob me off.
I have contacted UK Power Networks countless times and they have sent round and Electrician on 2 occasions to inspect the Wiring before and after the electricity meter, both times finding no faults. (We have TNCS wiring).

So I complained again and they sent round an engineer to fit a Voltmeter before the electricity meter which was here for a month. The results (which I have a copy of somewhere) and the accompanying letter confirm that my voltage continuously exceeds the maximum of 253 on multiple occasions. However no action has yet been taken (over a year later) and last night I was woke up and 4am by my three UPS units beeping with a voltage of 261V!!!

Despite having 2 of their electricians verify there are no problems with my house wiring, and also verifying the voltage from before the electricity meter with my house disconnected, one thing that the UK Power Networks have repeatedly told me is that it may be the house wiring causing the voltage to go up due to a poor connection. However surely a poor connection would lower the voltage? I asked the second of their electricians about this and he just looked at me blankly and couldn't answer. And they also can't explain why the voltage was so high with the house disconnected.

I have been taking the readings from the voltmeters on 3 APC UPS and also my Fluke DMM. All of these meters, and also the one from the Electricity company from that time, are all within <0.1V of each other.

Can anyone make a suggestion what I should do? I am very concerned about this potentially causing a fire.

Additionally whenever it goes above 254V the central heating timer crashes and needs to be manually rebooted. This is very annoying.
 

Offline mikeselectricstuff

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Re: Constant High Mains Voltages At Home
« Reply #1 on: April 16, 2021, 05:59:50 pm »
I wonder if a neighbour has an EV charger - a high overnight load on a different phase, and a less-than perfect neutral might cause this.
Might be interesting to measure the voltage between your TNCS earth and "real" earth outside - a significant voltage might indicate a Neutral issue outside
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Offline Ice-Tea

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Re: Constant High Mains Voltages At Home
« Reply #2 on: April 16, 2021, 06:08:03 pm »

Offline themadhippy

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Re: Constant High Mains Voltages At Home
« Reply #3 on: April 16, 2021, 06:23:46 pm »
Quote
Can anyone make a suggestion what I should do?
send british gas invoices for all the electrical equipment  damaged by the over voltage starting with the ups
 

Offline IanB

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Re: Constant High Mains Voltages At Home
« Reply #4 on: April 16, 2021, 06:44:45 pm »
Despite having 2 of their electricians verify there are no problems with my house wiring, and also verifying the voltage from before the electricity meter with my house disconnected, one thing that the UK Power Networks have repeatedly told me is that it may be the house wiring causing the voltage to go up due to a poor connection. However surely a poor connection would lower the voltage? I asked the second of their electricians about this and he just looked at me blankly and couldn't answer. And they also can't explain why the voltage was so high with the house disconnected.

I think Mike has a good observation here. The stability of your mains voltage depends strongly on having a good solid neutral connection back to the substation transformer. This neutral is like an "anchor" that keeps the voltage where it should be. If there was any kind of neutral fault between you and the substation, and there was an unbalanced load on another phase, then your voltage could get pushed up.

That said, if there is a neutral fault it would more likely be out in the street and not inside your property boundary.

I think you have to keep chasing your local DNO (UK Power Networks?) and push them to do something. You need to get their engineering staff involved. Complaining to British Gas won't help as they only sell you the electricity, they don't supply it.

It seems like if you have already had your voltage recorded by the supply company there is evidence of a problem. If they are not acting, you need to escalate--Regulator? Ombudsman?

Good luck.
 

Online Siwastaja

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Re: Constant High Mains Voltages At Home
« Reply #5 on: April 17, 2021, 12:17:39 pm »
There is very little you can do, technically. The problem is technical, but something you can't fix because the problem likely isn't in equipment you own, and you are not allowed to fix it. So the problem is only bureaucratic. By refusing to fix it, the power company is actually making it political. I don't see any other choice than to find out what authority is responsible for overseeing power companies. It seems you need legal advice, I'm pretty sure some authority offers it for consumers free of charge.

I would likely inform the power company that due to the inability to provide their part of the agreement (i.e., supply electric power within specifications), I see the contract is void from now on. Then install a massive genset to supply your needs, until the electric company is able to provide you power again.

This gets interesting if law requires you to buy energy from the grid. You can't satisfy this law if the power company can't supply you, anyway, but apparently everything is seemingly well as long as the power company is able to invoice you.
 

Online jonpaul

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Re: Constant High Mains Voltages At Home
« Reply #6 on: April 17, 2021, 12:40:58 pm »
Hello

Check out the notorious UK "Ring Bus" distribution system. Well known for very high line voltages.

Deep in the UK regulations there may exist a legal limmit to line voltage. You can inform your UK Govt representative of any excess beyond the regulatory limit.

We use line monitors and regulators if the voltage is too high.

A simple buck autotransformer can bring it down by 3-20%.

A Variac variable transformer  is not as efficient or as compact but can work.

Kind Regards,

Jon
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Offline tszaboo

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Re: Constant High Mains Voltages At Home
« Reply #7 on: April 17, 2021, 12:57:46 pm »
Well, if there is a lot of load on 2 phases out of 3, that can shift the neutral. If there is really bad wiring on your feed. (outside the house, in your street)
I would document the overvoltage, and sue the DSO.
Or maybe there is a customer protection group, that you should contact.
 

Offline iJoseph2

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Re: Constant High Mains Voltages At Home
« Reply #8 on: April 17, 2021, 03:02:27 pm »
Would it be sensible to sue your energy supplier or UK Power Networks via the small claims court every time a piece of your equipment is broken? But you'd probably have to show due diligence to get your money back before going ahead with court proceedings.

Obviously you'd be liable for their legal costs if they win, but if you have THEIR evidence of a fault I'd find it hard to believe you'd lose.

As long as you get payment each time you would only lose your time. Hopefully eventually someone responsible fixes the fault.
 

Offline tszaboo

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Re: Constant High Mains Voltages At Home
« Reply #9 on: April 17, 2021, 03:05:28 pm »
Would it be sensible to sue your energy supplier or UK Power Networks via the small claims court every time a piece of your equipment is broken? But you'd probably have to show due diligence to get your money back before going ahead with court proceedings.

Obviously you'd be liable for their legal costs if they win, but if you have THEIR evidence of a fault I'd find it hard to believe you'd lose.

As long as you get payment each time you would only lose your time. Hopefully eventually someone responsible fixes the fault.
Why would you want to go to court.
You sue them, they will either fix your problem, or settle. Why would they want to go to court.
Its about getting their attention.
 

Offline madires

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Re: Constant High Mains Voltages At Home
« Reply #10 on: April 17, 2021, 03:50:22 pm »
Ofgem?
 

Online jonpaul

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Re: Constant High Mains Voltages At Home
« Reply #11 on: April 18, 2021, 09:04:38 am »
Hello again: Lawsuits are useless here and only make money for the lawyers.

Often the regulations are loosened with time.

https://www.twothirtyvolts.org.uk/pdfs/site-info/Explanation_230Volts.pdf

I think the applicable PRE BREXIT reg of EU was European Standard EN50160. = 207 Volts to 253 Volts.  That may change post Brexit!

High VARS (excess capacitance eg from PFC) can cause resonant voltage rise in HV transmission and distrib line.

I would document the issues with a 24/7 line V monitor, for a few weeks, then send the chart with max/min leagl V outlined to the Sys Op of the local utility and to a local lawmaker, noting that the high line V can pose a danger to consumers.

Kind Regard,

Bon Chance

Jon
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Offline richard.cs

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Re: Constant High Mains Voltages At Home
« Reply #12 on: April 18, 2021, 12:42:40 pm »
UK Power Networks are the ones to deal with here, the fault is with their network, and it's their responsibility to fix it. British Gas won't be the slightest bit interested, but if they were all they could do is lean on UKPN on your behalf. Usually the problem is getting them to accept that there is a fault - inaction after getting clear evidence from a logger they installed is unusual. To me this suggests they know what it is and that it's a network design issue rather than a fault as such (and therefore very expensive to fix). If it was a high resistance neutral joint they would have fixed it by now because that causes a lot of other problems, and would be likely to get progressively worse.

On a technical level it seems very likely that you're on a part of the network with a relatively high impedance, if they could simply have changed a transformer tapping down then they would probably have done so already - most likely they can't because then at other times of day the voltage would be too low, not necessarily for you but for some customers on the same transformer. A large overnight load that is on another phase is the most likely cause as others have said, in conjunction with a fairly high resistance neutral, probably not faulty just long and thin. Unbalanced loads on the local HV network would could also cause this, but this is less likely. Basically it sounds like your area is in need of expensive network reinforcement and they're trying to avoid it.

The upper limit is 253 V, it's set in the The Electricity Safety, Quality and Continuity Regulations 2002 and will not be changing due to Brexit. https://www.legislation.gov.uk/uksi/2002/2665/regulation/27/made This is the piece of legislation that they must comply with to avoid heavy fines, and it's what you will need to use to beat them up with. Essentially you need to write to them with the evidence that they are in breach of their obligations and then take it to Ofgem if they ignore you. Separately you can also take them to small claims court for damage to appliances, etc. but only once you have tried the other methods. For those not familiar with the process, in the UK there is a specific procedure you can use for claims under £10,000 which is designed to be low cost and complexity and which does not require you to have legal representation. They specifically cannot claim for their legal fees if you loose, your liability is limited to their reasonable expenses for time, etc. Often big companies just no-show as it's not worth their time and you win by default, see here: https://www.moneysavingexpert.com/reclaim/small-claims-court/

I'm guessing you're somewhere relatively rural and a single-phase customer? Perhaps with overhead distribution, and maybe even on a split phase piece of network? How far are you from the transformer? Is it large or small, does it have 2 HV bushings or 3? Is it rusty (usually indicates severely overloaded, the paint burns off at a lower temperature than the transformer actually fails)? What's your earthing system (do they supply an earth terminal or do you have a rod)?

How low does your mains voltage dip at other times? If not too low then as an interim fix you could buy and install a transformer that takes ~10% off your incoming voltage for a couple of hundred quid, it's far from ideal, but if it stops expensive things failing it might be worth it.

The 315 V is the most worrying, high enough to cause damage, and also more suggestive of a bad neutral joint somewhere than just a general high resistance. It is possible that they've fixed a neutral joint quietly, preventing the 315 V but leaving you with the ~270 V. Options to force disconnection at high voltage exist, but are a bit ugly.
 
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Offline ConKbot

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Re: Constant High Mains Voltages At Home
« Reply #13 on: April 18, 2021, 02:37:55 pm »
Hello again: Lawsuits are useless here and only make money for the lawyers.

Does the UK have small claims court though? The US has "small claims court" to settle up smaller grievances, where there's no lawyers for individuals, formality on procedures is a bit more lax given that., and associated costs are lower.

For the OP,  sounds like they are more than willing to provide you enough evidence, checking out your wiring saying it's fine, (even better that its their representative saying that) acknowledging their problem after the logging.

You can also try the "woe is me I'm sleep in fear every night that the power company is going to set my fridge on fire and burn down my house"  angle with the local news.  Get a meter in the wall reading an excessively high voltage and do your best to ham up some B-roll footage for the news, and talk to them about devices that keep getting burned up and how you feel helpless and no one will do anything etc. Has enough drama and anger inducing aspects that they may pick up the story for a slow night.
 

Online coppice

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Re: Constant High Mains Voltages At Home
« Reply #14 on: April 18, 2021, 02:50:31 pm »
315V is really nasty. Most products have not even been type tested at such a high continuous voltage, and for a good reason. Almost anything with a MOV at the inlet is going to get that MOV seriously hot at 315V.
 

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Re: Constant High Mains Voltages At Home
« Reply #15 on: April 18, 2021, 03:16:35 pm »
Broken PEN conductor?  Rare, but does happen.  This would allow for a shift between your local earth and the substation earth, especially if your local earth isn't very good.

Difficult to detect as a broken PEN conductor could lie beyond your premises.  Did they specifically check for PEN fault?
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Offline NiHaoMike

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Re: Constant High Mains Voltages At Home
« Reply #16 on: April 18, 2021, 07:17:39 pm »
Similarly a few years back I had a new AC unit installed, and the 24V control fuse kept popping every day, with no resolution from the installation company other than coming everyday to replace it and try to persuade me into buying their mains voltage stabilizer and damage insurance.

Again I had to dig into the problem myself and found out the control wire bundle had some insulation damages and instructed the technician to rewire the thing using some spare strands to replace the bad ones, since then the AC never failed again AFAIK till I sold the house.

As the previous case, I paid more than generously, I paid all $5000 they had asked for without a question for a $1700 Goodman unit, and that's what I got from a $3300 service fee.
Not sure about how it is in China, but in the US, it really sounds like DIY would be the way to go even after factoring in the cost of tools and time to learn how to do it right including getting an EPA 608.
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Offline gnuarm

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Re: Constant High Mains Voltages At Home
« Reply #17 on: April 18, 2021, 08:24:38 pm »
I wonder if a neighbour has an EV charger - a high overnight load on a different phase, and a less-than perfect neutral might cause this.
Might be interesting to measure the voltage between your TNCS earth and "real" earth outside - a significant voltage might indicate a Neutral issue outside

EV home charging doesn't use that much electricity.  I've had many discussions with people in the UK about EV charging, but I don't recall the numbers.  However, it is not so much different from using two or three tea kettles at once and is comparable to the central hot water heater being on.  My water heater is 4.4 kW.   Charging my car on a 40 amp circuit would use about 8 kW.  If one user on a three phase supply with each home only getting a single phase would see a smaller rise in voltage than the high current user sees as a drop because of the three phases being 120 degrees out of phase and not 180.

I think what might be happening is simply the net loading on the transformer.  At night it is lower, so you will see a higher voltage due to lower resistive losses as will the other homes.  This would be similar to disconnecting your house load making the voltage on the line rise. 

I used to be in a UK ham mailing group called RSGBtech.  I recall lots of similar discussions and in particular someone was able to resolve such an over voltage.  Maybe you could ask there how the guy got the power company to adjust the transformer.  They have multiple taps just for this purpose. 
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Offline mikeselectricstuff

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Re: Constant High Mains Voltages At Home
« Reply #18 on: April 18, 2021, 10:16:57 pm »
I wonder if a neighbour has an EV charger - a high overnight load on a different phase, and a less-than perfect neutral might cause this.
Might be interesting to measure the voltage between your TNCS earth and "real" earth outside - a significant voltage might indicate a Neutral issue outside

EV home charging doesn't use that much electricity. 
32A/7kW typically
Quote
I've had many discussions with people in the UK about EV charging, but I don't recall the numbers.  However, it is not so much different from using two or three tea kettles at once and is comparable to the central hot water heater being on. 
The difference is that it's a continuous  load for many hours - most others are either short term (kettle/shower) , or cycling on/off (oven, heating)
Quote
I think what might be happening is simply the net loading on the transformer.  At night it is lower, so you will see a higher voltage due to lower resistive losses as will the other homes.  This would be similar to disconnecting your house load making the voltage on the line rise.
Probably the  most likely, but not for going as high as 315V - that looks more like a neutral issue 
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Offline gnuarm

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Re: Constant High Mains Voltages At Home
« Reply #19 on: April 18, 2021, 11:32:19 pm »
I wonder if a neighbour has an EV charger - a high overnight load on a different phase, and a less-than perfect neutral might cause this.
Might be interesting to measure the voltage between your TNCS earth and "real" earth outside - a significant voltage might indicate a Neutral issue outside

EV home charging doesn't use that much electricity. 
32A/7kW typically
Quote
I've had many discussions with people in the UK about EV charging, but I don't recall the numbers.  However, it is not so much different from using two or three tea kettles at once and is comparable to the central hot water heater being on. 
The difference is that it's a continuous  load for many hours - most others are either short term (kettle/shower) , or cycling on/off (oven, heating)

Not sure what you mean.  The hot water heater can be on for an hour easily when people use the shower.  My furnace has a 10 kW heating coil.  That's more than my car will draw other than at a Supercharger and there are times when it runs all night trying to keep up with the winter cold. 

Even for short duration loads, the point is the car is not much more of an impact to the line voltage. 

We don't have the same issue in the US with unbalances in the distributed power.  The final run is typically a high voltage single phase pair with a transformer to step down from maybe 7 kV to 240 volts as a split phase that runs to one to four houses typically.  One house drawing more power than the others never unbalances the voltages. 

In reality, none of that matters.  If a customer is using power and it causes the voltage to be excessive at another customer's premise, that is a fault in the power distribution.


Quote
Quote
I think what might be happening is simply the net loading on the transformer.  At night it is lower, so you will see a higher voltage due to lower resistive losses as will the other homes.  This would be similar to disconnecting your house load making the voltage on the line rise.
Probably the  most likely, but not for going as high as 315V - that looks more like a neutral issue

I guess someone really likes tea... late at night.
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Offline Monkeh

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Re: Constant High Mains Voltages At Home
« Reply #20 on: April 19, 2021, 02:08:17 am »
Not sure what you mean.  The hot water heater can be on for an hour easily when people use the shower.  My furnace has a 10 kW heating coil.

The vast majority of properties in the UK use gas, and most people do not take hour long showers.
 

Offline gnuarm

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Re: Constant High Mains Voltages At Home
« Reply #21 on: April 19, 2021, 02:11:37 am »
Not sure what you mean.  The hot water heater can be on for an hour easily when people use the shower.  My furnace has a 10 kW heating coil.

The vast majority of properties in the UK use gas, and most people do not take hour long showers.

So how does any of that affect EV charging??? 
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Offline Monkeh

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Re: Constant High Mains Voltages At Home
« Reply #22 on: April 19, 2021, 02:28:23 am »
Not sure what you mean.  The hot water heater can be on for an hour easily when people use the shower.  My furnace has a 10 kW heating coil.

The vast majority of properties in the UK use gas, and most people do not take hour long showers.

So how does any of that affect EV charging???

If the car is set to charge very late at night when almost all other loads are not present and there's a bad neutral you could see a serious excess voltage event on other phases. Same with any other large load, but I'll give you a guess what relatively unusual and new large, overnight load is being seen on the networks..
 

Offline gnuarm

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Re: Constant High Mains Voltages At Home
« Reply #23 on: April 19, 2021, 03:02:33 am »
Not sure what you mean.  The hot water heater can be on for an hour easily when people use the shower.  My furnace has a 10 kW heating coil.

The vast majority of properties in the UK use gas, and most people do not take hour long showers.

So how does any of that affect EV charging???

If the car is set to charge very late at night when almost all other loads are not present and there's a bad neutral you could see a serious excess voltage event on other phases. Same with any other large load, but I'll give you a guess what relatively unusual and new large, overnight load is being seen on the networks..

You pointed out the problem, "bad neutral".  Get that fixed! 

One more reason why I'm glad I'm in the US.  The neutral doesn't carry any major loads. 
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Offline Monkeh

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Re: Constant High Mains Voltages At Home
« Reply #24 on: April 19, 2021, 03:10:17 am »
You pointed out the problem, "bad neutral".  Get that fixed!

That has been the point of discussion from the beginning. You just haven't been able to see past your assumption EVs were being blamed.

Quote
One more reason why I'm glad I'm in the US.  The neutral doesn't carry any major loads.

And yet a bad neutral on a property in the US causes very much the same problem.
 


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