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Faulty Electricity Meter?

Discussion in 'Electrics UK' started by Deryck Tintagel, 8 Jul 2021.

  1. Deryck Tintagel

    Deryck Tintagel

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    I take monthly readings for my energy supplier and submit via their website. I have noticed this month and last month that the usage is considerably lower than I would expect.

    The average of "normal" monthly usage is about 250kWh. Last two readings are 168kWh and 116kWh. Looking back to the same months over the last couple of years the usage is about 230~240kWh.

    Nothing has changed as far as usage is concerned - oven is the biggest user and I don't think that is faulty.

    Would a meter really show this much difference, i.e. read low? I don't fancy being charged for a meter test if there is nothing wrong. I may have a current clamp I could borrow from work to check when loads are applied
     
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  3. blup

    blup

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    Given previous readings, the current ones seems low especially given the average household use is around 300kwh. So unless it was faulty before and has righted itself, it would appear to be faulty now. A clamp meter might shed some light on this, they can be obtained cheaply from amazon.

    Blup
     
  4. winston1

    winston1

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    Don’t ask for one then. If their meter is faulty (in your favour), which I doubt, it would be unreasonable of them to ask you to back pay for energy you might have used.

    Meters rarely go faulty, more likely something you have forgotten.

    Clamp meters are unreliable because they only measure current and assume a voltage that can vary, and take no account of power factor. If you have low power factor loads they will invariably read high reenforcing your impression of a faulty meter even though most likely it is not (faulty).
     
  5. Deryck Tintagel

    Deryck Tintagel

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    Well, it certainly looks like it is my favour and any back payment would only be two months (so far) as the readings until May were all about right at 250kWh. I am sure they would want payment!

    However, I thought a bit and did some rough maths on just the oven:

    Double oven but use only the main fan assist oven on the whole - guess at 4kW used for about 1 hour per day so 4kWh per day > 28kWh per week > 120kWh per month (roughly). So that would account for total usage in the last month. So the rest of the appliances in the house could use 120kWh over the month - possible with washng machine and tumble dryer. Seems very odd that the usage has been 250kWh for years and it has suddenly dropped
     
  6. zebedee2001

    zebedee2001

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    Is this a mechanical meter or a smart meter? My parents have twice had to have their smart meter (gas one) replaced due to it going haywire & running up bills of several thousand pounds. It possible for it to go the other way too.

    If it is in your favour I would keep quiet.

    Obviously just remember that you probably are using less energy in the summer compared with other months.
     
  7. Deryck Tintagel

    Deryck Tintagel

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    It is a mechanical meter - I refused the smart one a while ago!

    Electricity usage is between 200~300kWh per month throughout the year so it is a bit strange that it has droppd so much. I think I will keep an eye on it for a month or two to see what happens as we move into winter.

    Just been thinking a bit more... the oven will not be on at 4kW all the time and possibly only averages only 1kWh. So that would reduce the consumption to about 30kWh per month.

    just wonder what might have been using the rest of the power. More thinking!
     
    Last edited: 8 Jul 2021
  8. AdrianUK

    AdrianUK

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    How do you create hot water?
     
  9. crystal ball

    crystal ball

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    Back in the days of local boards a "nil advance" would be noted and a tag placed on the meter readers paperwork, if it persisted there would be an investigation,maybe a check meter installed for a while
     
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  11. JohnD

    JohnD

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    A 4kW oven does not use 4kWh an hour.

    It uses 4kW for maybe 10-15 minutes while it is heating up from cold, then ticks on and off according to the thermostat a few minutes at a time.

    A tumble drier uses around 3kW continually, although heat pump driers are much less.

    An electric immersion heater uses 3kW continually until the cylinder is hot, maybe 90 minutes. Unless it is faulty, which is not unknown and can be very dangerous.

    An electric shower uses a huge amount for (hopefully) a short time.

    I was given a old-fashioned fridge, and when I replaced it with a modern one, the electricity bill dropped by nearly a hundred pounds a year. Because it runs 24 hours a day, 365 days a year.

    An electric heater uses a lot. Especially one you have put in shed, cellar or loft to protect against frozen pipes, and forgotten about.

    See if you can pick up an electricity monitor cheap on ebay, they used to be very popular and even given away by energy companies, before so-called smart meters arrived. I use an Owl. British Gas and Southern Electric versions were also popular. They have a remote wireless display. The best Owl version sells for more because it can connect to a PC with a USB connector if you want, the others go for around £15
     
  12. winston1

    winston1

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    Wot I said:

    Clamp meters are unreliable because they only measure current and assume a voltage that can vary, and take no account of power factor. If you have low power factor loads they will invariably read high
     
  13. JohnD

    JohnD

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    Yes, the voltage in my house varies between 242 and 248.

    Not significant.

    And the only large power users are resistance loads in heaters.

    The base load of PC, fridge-freezers, things on standby, LED lamps is around 300W

    I can easily tell what else is being used.

    You do talk a lot of nonsense.

    Unreliable my asre.
     
  14. blup

    blup

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    IIRC suppliers cannot recover incorrectly billed charges after 12 months. A reasonable timescale to check your annual usage

    Blup
     
  15. SUNRAY

    SUNRAY

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    I have heard this mooted a few times so...
    My advice is to open a deposit account and transfer an amount into it every month to cover the amount you think is under metered.
     
  16. winston1

    winston1

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    Lets say the clamp meter is calibrated for 230v unity power factor. For simplicity lets say it measures 1 amp so quotes 230watts. But with your variation the actual power would be between 242 add 248 watts. That is an error of up to almost 8%.

    Of course some people have loads other than resistive. Those clamp on meters are definitely unreliable. If they were so good why aren't they used instead of the expensive meters that are used for billing?
     
  17. JohnD

    JohnD

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    I can tell the difference between 325 watts and 3325.

    It's quite easy when you know how to read figures

    So I know when the immersion heater is on.

    I also happen to know what times of day and weather conditions cause the voltage to go up. But it doesn't matter because I can see quite clearly when a heating element comes on.

    What do you think the OP needs to be looking for?
     
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