Author Topic: Constant High Mains Voltages At Home  (Read 19108 times)

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Offline bdunham7

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Re: Constant High Mains Voltages At Home
« Reply #25 on: April 19, 2021, 04:34:40 am »
One more reason why I'm glad I'm in the US.  The neutral doesn't carry any major loads.

I think a few data centers went up in flames because of that assumption, before PFC became relatively normal on PSUs.  If you have a three-phase wye supply feeding PSUs without PFC, the current in the neutral will be 3X that in the phases when you otherwise would expect near zero.  And on certain allowed-but-shouldn't-be configurations in residential use (home runs with shared neutral), losing neutral can cause your 120V socket to be 240 volts and that can be very exciting.

A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Offline gnuarm

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Re: Constant High Mains Voltages At Home
« Reply #26 on: April 19, 2021, 04:48:29 am »
One more reason why I'm glad I'm in the US.  The neutral doesn't carry any major loads.

I think a few data centers went up in flames because of that assumption, before PFC became relatively normal on PSUs.  If you have a three-phase wye supply feeding PSUs without PFC, the current in the neutral will be 3X that in the phases when you otherwise would expect near zero.  And on certain allowed-but-shouldn't-be configurations in residential use (home runs with shared neutral), losing neutral can cause your 120V socket to be 240 volts and that can be very exciting.

You will need to explain that one. 
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Offline bdunham7

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Re: Constant High Mains Voltages At Home
« Reply #27 on: April 19, 2021, 05:14:27 am »
One more reason why I'm glad I'm in the US.  The neutral doesn't carry any major loads.

I think a few data centers went up in flames because of that assumption, before PFC became relatively normal on PSUs.  If you have a three-phase wye supply feeding PSUs without PFC, the current in the neutral will be 3X that in the phases when you otherwise would expect near zero.  And on certain allowed-but-shouldn't-be configurations in residential use (home runs with shared neutral), losing neutral can cause your 120V socket to be 240 volts and that can be very exciting.

You will need to explain that one.

Which one?

On a single split-phase system:  Suppose you have two 120 volt circuits that are on opposite sides and share a neutral.  You plug a space heater and a light bulb into each circuit and you have a balance--no neutral current.  Then your neutral breaks or becomes disconnected--nothing happens, still balanced.  Then one space heater turns off--what happens to the light bulb on that circuit?

On the three phase example:  If you have a 208/120 wye three-phase service for three-phase and single-phase use, you normally size the neutral the same as the phases.  If only one phase has a load, then that phase and the neutral see the same current.  If  you add some load to the other phases, the neutral current goes down.  If they are all equally loaded, the neutral current is zero.  That's the theory anyway, and it works as long as the current waveform is more or less sinusoidal, phase doesn't matter as long as they are all the same too.

A non-PFC PSU, or anything powered with rectifier and filter capacitor, has a completely non-sinusoidal current load.  A nominal current of 1 amp might actually be a peak current of 3 amps with a 60-degree conduction angle (120 degrees per cycle) which results in 3X the I2R heating.  That is would affect both phase and neutral and is the reason these types of devices usually require derating of the service wiring.  However, if you connect these to your three-phase service, you might think the load would balance out--and some people did think that.  However, since the conduction periods don't overlap, adding a load like this to the other phases doesn't result in the neutral current going down, rather they add.  So if you were completely unaware of the way these devices work and you expected the load to react the same as say incandescent lighting or induction motors, you end up with 3X the anticipated I2R heating on the phases and 9X on the neutral.  This could theoretically happen with any load with a very poor harmonic power factor, perhaps lighting ballasts or other things.  But I've only really heard about it with data centers.
« Last Edit: April 19, 2021, 05:26:39 am by bdunham7 »
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Offline richard.cs

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Re: Constant High Mains Voltages At Home
« Reply #28 on: April 19, 2021, 10:11:48 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???

In the UK, in non-gas houses, domestic stored water heating is typically 3 kW heating a ~200 L low-pressure tank. Instant heating for showers is also common often around 7- 10 kW and is often found in houses that do have gas as it's a cheap way to add an extra shower and is at mains pressure. The most likely candidate for high loads at night is not EV charging but storage heaters, 5-10 kW for up to 7 hours overnight heating some big ceramic bricks on cheap(ish) night rate electricity for later use as daytime heat. The electric car thing is probably a red herring.

I still think it's more likely to be a generally high resistance neutral from being long and thin and underspec'd for the loads rather than a faulty joint. A bad joint would most likely have been fixed or caught fire by now. Historically undersized neutrals were common on the assumption of at least some balance between phases and before anyone worried about harmonic currents (1960s and earlier).
 

Offline SeanB

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Re: Constant High Mains Voltages At Home
« Reply #29 on: April 19, 2021, 10:48:05 am »
Yes undersized neutral was common when the high power loads were all resistive or inductive, like heating and motor loads, so the neutral only had to carry a difference current equal to the household current rating over the 3 phase set of connections. Typically was 60% of the conductor diameter for the phases, and the same for the PE conductor, though TNC-S uses the same conductor instead.  done when copper prices peaked, to lower the cost of building out networks for the utility operators and municipalities. That changed when switching supplies became common, and the first use was in TV sets, where you suddenly had large DC current flows in the neutral, and this accumulated as the TV sets tended to turn on the thyristor power supplies late in the voltage waveform, so the neutral current was massive. Led to quite a few substations blowing up as the DC current flow through the windings saturated the core, and then in turn the primary side current was not limited, except by the winding resistance and the lower air core inductance, leading to massive heating and failure.

The current thing is to size neutral to the same as phase conductor, though with increasing use of PFC for larger loads the neutral current ca be lower, but there are still large numbers of loads with poor power factor, including LED lights, especially those with trailing edge dimming, as you get pretty high current flow where the corresponding other 2 phases are not going to draw current out via the neutral. A lot of cheaper appliances also forego PFC, because that makes them cheaper, and thus you get the high peak current pulses.

If the high mains is all of a sudden, and there are no new developments by you, then it is a failing neutral, and you are on the lowest loaded phase, or the neutral at the substation is burnt out already, and open circuit, or the cable has been stolen. Complain to the power company again, and to your local municipality that your house and equipment is at risk, and that you will have damaged equipment from this, along with the increased risk of a fire from failed equipment.
 

Offline richard.cs

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Re: Constant High Mains Voltages At Home
« Reply #30 on: April 19, 2021, 11:06:57 am »
Claiming for damaged items on your insurance may also help as there's a good chance the insurer will then try to recover costs from UKPN - might make them pay attention.
 

Offline paul_g_787Topic starter

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Re: Constant High Mains Voltages At Home
« Reply #31 on: April 19, 2021, 01:02:25 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.

Yes, I have suspected that there is an issue that they know about which they are not willing to fix. I live in a small village, well now it is technically a town. They have built several housing estates here over the last 5 years and I suspect that the wiring to our town is just not 'big' enough to cope.

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)?

As I said, a small town, we about 3 miles from the 'big' town.
We have underground distribution.
I am less than 1 mile from the transformer.
I am not sure if it has 2 or 3 HV bushings or of the condition of the transformer as I have never seen it, it is in a small brick out building at the end of the street.
My earthing system is TNCS: so no 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.

The voltage, the lowest I see it on average is about 245V and that is lately during lockdown where everyone is at home. Before last March never lower than 248.

The electrician that came round last year before the voltage logger was installed told me that I am on one of 3 phases. I am the last house on the phase and that the transformer is set to 249V (Which is what I usually get). He disconnected my house from the supply and tested the connections and concluded the fault is further up the line, then he booked the voltage logger to be installed.

So this suggests to me that the wiring from the transformer is fine.

I highly suspect that they are setting the voltage higher to cope for the increased load from the new build estates. Although this is just suspicion and I have nothing to prove this.
 

Offline gnuarm

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Re: Constant High Mains Voltages At Home
« Reply #32 on: April 19, 2021, 04:47:11 pm »
You will need to explain that one.

Google zero sequence current.

You have not been paying attention.  in the US we do not bring three phase into the home. 
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Offline gnuarm

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Re: Constant High Mains Voltages At Home
« Reply #33 on: April 19, 2021, 05:01:07 pm »
One more reason why I'm glad I'm in the US.  The neutral doesn't carry any major loads.

I think a few data centers went up in flames because of that assumption, before PFC became relatively normal on PSUs.  If you have a three-phase wye supply feeding PSUs without PFC, the current in the neutral will be 3X that in the phases when you otherwise would expect near zero.  And on certain allowed-but-shouldn't-be configurations in residential use (home runs with shared neutral), losing neutral can cause your 120V socket to be 240 volts and that can be very exciting.

You will need to explain that one.

Which one?

On a single split-phase system:  Suppose you have two 120 volt circuits that are on opposite sides and share a neutral.  You plug a space heater and a light bulb into each circuit and you have a balance--no neutral current.  Then your neutral breaks or becomes disconnected--nothing happens, still balanced.  Then one space heater turns off--what happens to the light bulb on that circuit?

This is the same problem that is found with three phase circuits.  Lose the neutral and the voltage seen is at the mercy of the load balance.  In US homes, we put the big loads on 240 tied across the full voltage without a connection to neutral.  So the loads are much  better balanced in general than running one of three phases to each home where one home can greatly unbalance the loads and muck the voltage to the other homes.


Quote
On the three phase example:  If you have a 208/120 wye three-phase service for three-phase and single-phase use, you normally size the neutral the same as the phases.  If only one phase has a load, then that phase and the neutral see the same current.  If  you add some load to the other phases, the neutral current goes down.  If they are all equally loaded, the neutral current is zero.  That's the theory anyway, and it works as long as the current waveform is more or less sinusoidal, phase doesn't matter as long as they are all the same too.

A non-PFC PSU, or anything powered with rectifier and filter capacitor, has a completely non-sinusoidal current load.  A nominal current of 1 amp might actually be a peak current of 3 amps with a 60-degree conduction angle (120 degrees per cycle) which results in 3X the I2R heating.  That is would affect both phase and neutral and is the reason these types of devices usually require derating of the service wiring.  However, if you connect these to your three-phase service, you might think the load would balance out--and some people did think that.  However, since the conduction periods don't overlap, adding a load like this to the other phases doesn't result in the neutral current going down, rather they add.  So if you were completely unaware of the way these devices work and you expected the load to react the same as say incandescent lighting or induction motors, you end up with 3X the anticipated I2R heating on the phases and 9X on the neutral.  This could theoretically happen with any load with a very poor harmonic power factor, perhaps lighting ballasts or other things.  But I've only really heard about it with data centers.

Yeah, non-linear loads are a bitch.
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Offline geggi1

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Re: Constant High Mains Voltages At Home
« Reply #34 on: April 19, 2021, 09:03:41 pm »
From my experience as  HV / LV electrician and electrical engineer the large variation in voltage between phase and neutral indicate that there is a bad connection in the PEN conductor. If you got a 3 phase installation in your house you can find if there are a bad connection in the PEN conductor by loading up one of the phases more than the oter ones and measure the voltage phase to neutral on all phases. If the voltage differs a lot between the phases there is something wrong on the PEN.
You will have to get the PEN conductor traced back its origin to find the fault, but its probably located where there are splices. A good place to start is in your fuse panel.   
 

Offline IanB

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Re: Constant High Mains Voltages At Home
« Reply #35 on: April 19, 2021, 09:50:34 pm »
From my experience as  HV / LV electrician and electrical engineer the large variation in voltage between phase and neutral indicate that there is a bad connection in the PEN conductor. If you got a 3 phase installation in your house you can find if there are a bad connection in the PEN conductor by loading up one of the phases more than the oter ones and measure the voltage phase to neutral on all phases. If the voltage differs a lot between the phases there is something wrong on the PEN.
You will have to get the PEN conductor traced back its origin to find the fault, but its probably located where there are splices. A good place to start is in your fuse panel.

This is what other people above have thought. However, in the UK, houses do not get three phase service. You typically get three phases and a neutral carried down the street, and then each house gets just one of phases and the neutral brought into the property.
 

Offline Monkeh

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Re: Constant High Mains Voltages At Home
« Reply #36 on: April 19, 2021, 11:53:19 pm »
From my experience as  HV / LV electrician and electrical engineer the large variation in voltage between phase and neutral indicate that there is a bad connection in the PEN conductor. If you got a 3 phase installation in your house you can find if there are a bad connection in the PEN conductor by loading up one of the phases more than the oter ones and measure the voltage phase to neutral on all phases. If the voltage differs a lot between the phases there is something wrong on the PEN.
You will have to get the PEN conductor traced back its origin to find the fault, but its probably located where there are splices. A good place to start is in your fuse panel.

This is what other people above have thought. However, in the UK, houses do not get three phase service. You typically get three phases and a neutral carried down the street, and then each house gets just one of phases and the neutral brought into the property.

Irrelevant, it's a three phase supply.
 

Offline IanB

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Re: Constant High Mains Voltages At Home
« Reply #37 on: April 20, 2021, 03:42:17 am »
From my experience as  HV / LV electrician and electrical engineer the large variation in voltage between phase and neutral indicate that there is a bad connection in the PEN conductor. If you got a 3 phase installation in your house you can find if there are a bad connection in the PEN conductor by loading up one of the phases more than the oter ones and measure the voltage phase to neutral on all phases. If the voltage differs a lot between the phases there is something wrong on the PEN.
You will have to get the PEN conductor traced back its origin to find the fault, but its probably located where there are splices. A good place to start is in your fuse panel.

This is what other people above have thought. However, in the UK, houses do not get three phase service. You typically get three phases and a neutral carried down the street, and then each house gets just one of phases and the neutral brought into the property.

Irrelevant, it's a three phase supply.

Please explain. How would a weak neutral in your consumer unit lead to excessive voltages in your home?
 

Offline Monkeh

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Re: Constant High Mains Voltages At Home
« Reply #38 on: April 20, 2021, 04:02:40 am »
Please explain. How would a weak neutral in your consumer unit lead to excessive voltages in your home?

It wouldn't, so that's one less place to look. The rest of the post stands.
 

Offline IanB

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Re: Constant High Mains Voltages At Home
« Reply #39 on: April 20, 2021, 05:16:30 am »
It wouldn't, so that's one less place to look. The rest of the post stands.

That's fine then, since my only comment is about looking for the fault in the fuse panel. The rest of the thread has gone over the possibility of a poor neutral connection outside the house several times. That's old news by now.
 

Offline Alti

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Re: Constant High Mains Voltages At Home
« Reply #40 on: April 20, 2021, 09:07:24 am »
I highly suspect that they are setting the voltage higher to cope for the increased load from the new build estates. Although this is just suspicion and I have nothing to prove this.
+1
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Offline SeanB

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Re: Constant High Mains Voltages At Home
« Reply #41 on: April 20, 2021, 11:29:23 am »
Failing joint in the cable, easiest way for the supplier to find is to go back to the transformer via all the pedestals, and measure the voltage on that particular phase, looking for when it suddenly drops back to 249VAC as set by the transformer, and the fault is between the 2. Otherwise a long wire on the neutral to allow direct measurement of voltage drop between each point will work as well, though it will need to be a long wire, but does not really carry current other than meter burden.

New estates the typical thing is to force the builder to pay for the cable from the local transformer to the estate boundary, as they are the ones requesting the service, they pay for the cable and nstallation. Had that, where a house wanted meter upgrade, and they had to pay for the new cable from the pole to the new meter box, as well as the cable after the meter, as part of the installation cost. Another, upgrade from 60A single phase to 80A 3 phase, and had to pay for the new 25mm 4 core SWA cable from the substation to the meter box, as the existing cabling was running at full loading in the street distribution. Luckily only 60m of cable needed, and pay for the metro to dig the ditch, and lay it as well.
 

Offline geggi1

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Re: Constant High Mains Voltages At Home
« Reply #42 on: April 20, 2021, 01:33:14 pm »
When the grid is TNC or TNC-S the load is put between phase and neutral. The first poster on this tread said it where a TNC-S system. https://electrical-engineering-portal.com/erection-procedures-of-earthing-arrangements-tnc-tn-s-tnc-s-and-tt
Also from the first posting the highest voltage where 300 and something volts indicating the grid is a 400V system (system voltage form 380v to 410v depending on country and delivery regulations for electrical power)

The voltage between phases are 380-410v and this gives a phase to neutral of 219v to 237v. This is a vectoral value (complex numbers) but very simplified its the voltage phase to phase divided by the root of 3 (1,73).

On a 400V TNC-S system a 230V load is placed between one phase and neutral and get a voltage somewhere around  230V. A 400V load would be placed between two of the phases, but these loads are usually a 3phase load so the neutral don't matter and would normally not be connected to the load.

The PEN conductor is tied to the mains transformer star point to clamp the neutral voltage at 230V level. TNC-S systems always got Y connected windings on the secondary side of the mains transformer.
When the neutral (N / PEN) is disconnected this is called "Floating neutral". When the neutral is floating the voltages between the phases and neutral is dependent of the balances on all loads connected to the same transformer/circuit. The loads would work as a voltage divider so that the phase with the lowest load can get a voltage to neutral very close to the phase to phase voltage.

If you got a connected PEN conductor the voltage between neutral and protective earth will be close to nothing (1-5V normally). Any voltages higher than this is a solid indication of bad connections to the PEN and Neutral conductor. Its possible to check this with a regular multimeter but don't use the cheepo types because these might not withstand a voltage of up to 400v, use one rated for at least 500V.

A broken PEN conductor can cause current to run in the installations main earth bar and metal pluming for gas and water and the current can have a hight level because sit the current form all consumers that is connected to the broken PEN (internal and external). This can give dangerous voltage when getting in contact with metal parts connected to the earth system in the building and also damages to soldered joints in the plumbing.
 

Offline IanB

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Re: Constant High Mains Voltages At Home
« Reply #43 on: April 20, 2021, 01:49:32 pm »
The voltage between phases are 380-410v and this gives a phase to neutral of 219v to 237v. This is a vectoral value (complex numbers) but very simplified its the voltage phase to phase divided by the root of 3 (1,73).

And the voltages are even higher in this case. The UK supply is nominally 240/415 V, and in this case if the transformer is set to 249 V the phase voltage would be 431 V. Definitely not the kind of voltage you want getting into your house due to faults in the distribution system.
 

Offline paul_g_787Topic starter

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Re: Constant High Mains Voltages At Home
« Reply #44 on: April 22, 2021, 04:14:35 pm »
So just to clarify.

As a previous commenter said, in the UK we have three phase in the street, and each home (usually alternately 1, 2, 3) receives a single phase and neutral.

The engineer from UK Power Networks informed me that we have a TNC-S installation at my house.

When the engineer checked my meter and connections to the distribution board, he confirmed there were no bad connections including the Neutral which he suspected when he first arrived.

He also took voltage readings at the other end of the cable in the transformer building and informed me he was seeing the same voltages as at my house. He concluded that the fault is not at my property and is not with the neutral or other poor connection.

He also informed me that the transformer is set to 249V, which is the lowest voltage I see usually during the day time around 6pm.

Then he booked the voltage recorder which was fitted inside my meter cabinet. This was installed for 4 weeks. I went to the meter three times a day (and night) and recorded the voltage on the LCD display. The readings were identical to the voltage readings I took from my UPS.


So what could the fault be at this point? I am assuming that it is a fault with the equipment in the transformer building?
I want to try to get my head around this before writing to UK power networks so I can fully understand what is going on so as to avoid getting fobbed off again.
 

Offline IanB

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Re: Constant High Mains Voltages At Home
« Reply #45 on: April 22, 2021, 04:48:30 pm »
So what could the fault be at this point? I am assuming that it is a fault with the equipment in the transformer building?
I want to try to get my head around this before writing to UK power networks so I can fully understand what is going on so as to avoid getting fobbed off again.

I think you should try to keep away from technical troubleshooting and focus on the responsibilities of the supplier.

UK Power Networks have a legal and regulatory requirement to provide an electrical supply of appropriate quality. If they have documented evidence that your supply voltage is going out of spec they should be on the hook to take action.

When you write to them, you should remind them of the facts, provide evidence of costs you have incurred from damaged equipment, and insist they do something about it.

If you get no satisfaction you should take the problem to the regulator (Ofgem?)
 

Offline geggi1

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Re: Constant High Mains Voltages At Home
« Reply #46 on: April 22, 2021, 07:40:18 pm »
The fault is most likely somewhere in the grid outside your installation. By being outside your installation its the distribution company responsible to fix the problem. Depending a bit on the local legislation it might also be the distribution company that would have to pay for any damages to your installation/equipment caused by high or low voltage. In case of damages you should have the damages verified and documented by an intendant electrical engineer or electrician to claim replacement or repair.

Do also have a word with your neighbors if they got the same problems as you got. This can make a record to the distribution company that this is not just a single case. 
 

Offline paul_g_787Topic starter

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Re: Constant High Mains Voltages At Home
« Reply #47 on: April 22, 2021, 08:44:16 pm »
I am just trying to make sure I have done everything in my power so that I can prove it is not me at fault.

Annoyingly every time I phone UK Power Networks they just fob me off and say they will send an electrician but it will cost me £60. When I disagree they hang up.
 

Offline mikeselectricstuff

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Re: Constant High Mains Voltages At Home
« Reply #48 on: April 22, 2021, 10:32:39 pm »
I am just trying to make sure I have done everything in my power so that I can prove it is not me at fault.
As I mentioned earlier - try measuring/logging the voltage between the incoming neutral and a "real" earth from a rod or buried pipe/metalwork. Any significant voltage would be evidence of an upstream neutral fault
Youtube channel:Taking wierd stuff apart. Very apart.
Mike's Electric Stuff: High voltage, vintage electronics etc.
Day Job: Mostly LEDs
 

Offline Alti

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Re: Constant High Mains Voltages At Home
« Reply #49 on: April 23, 2021, 11:02:48 am »
I am just trying to make sure I have done everything in my power so that I can prove it is not me at fault. Annoyingly every time I phone UK Power Networks they just fob me off and say they will send an electrician but it will cost me £60. When I disagree they hang up.
You fight against a monopolist, good luck. Had these been rotten groceries, you'd have already found a suitable solution, without any complaints to the seller.

I'd collect data proving they breached the contract and that they new about the issue and ignored it and then take legal actions. This is not only about some UPSes but they are putting your life at risk. It really does not matter if that is 254V or 300V. In the meantime, use autotransformer for critical loads.
 


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