Investigation on massive electricity bills

[sparky1508]

Out of 28 circuits in main house only getting current flow on 2 and they are small 0.1 and 0.5 amps. Yet when I check flow from main DB on L3 it was 4.6 amps. Done IR and Continuity and all fine.

 

[sparky1508]

Meter readings all seem to coincide. Found out it's an actual meter reading every 6 months so every other quarter is an estimate based on last reading. Just checked the last two actual readings and in the 6 months usage was 28187 KWh. Think it's at 13p so that would work out at £3664. Please correct me if I'm wrong. Any other ideas welcome.

 

[martinwinlow]

Do you think that £4100 is acceptable for a quarter when they know they don't use a lot of electricity themselves. Clearly they don't want free electricity and I can assure you they quite well off but why would anyone pay for something that they are not using regardless of how much money they have. Really don't see the point in your comment.

I'm glad you even understood his/her comment. I do hope s/he isn't an electrician!

 

[streamer]

Is the detached cottage permanently let and is it off the same supply? Is there a sub meter to it? And are the stables used by the owners or let out to others?

 

[sparky1508]

Everything is from one meter (3 phase). Cottage is occupied by a couple that work for my clients. Barns and stables all used by my clients and nothing is rented out.

 

[Woofie]

No one, ever, thinks they use a lot of electricity. Can only think of one case where a customer's (shop) supply was also supplying the shop next door. Every other time they have simply used a lot of leccy. And, personally, I am pleased they are getting hammered for it financially. Once you have investigated the installation, prepare to advise them on how not destroy the one and only planet we can live on by. being a little more responsible in their choices. Probably try to not sound like the swivel-eyed environmentalist I am though.

 

[sparky1508]

Well the couple in the cottage have just got back and now the supply to the cottage is pulling anywhere between 10 and 37 amps sometimes sitting at a steady 17 but also sits at around 26. Something going on there. More detective work needed.

 

[Strima]

Worked on a Vodafone site a few years ago and had to find the origin. Traced the cable back to the Spar shop.

The manager was insistent that the site wasn't fed from his shop until we pointed out the cable going through his wall.

Was supplied off his DB and not a sub meter in sight, they'd been paying Vodafones bills for years...

 

[buzzlightyear]

are they producing &selling bob hope, you need to gain access in the cottage and see what is going on !

 

[sparky1508]

are they producing &selling bob hope, you need to gain access in the cottage and see what is going on !

Just been in and the only circuit pulling any significant current is the cooker at 6.6 amps. Don't know why it kept spiking but it's only since they got home. L1 was pretty much inactive until try arrived then starts spiking at 36 amps at times.

 

[buzzlightyear]

Is their any thing leaving from their board going out has a sub!

 

[sparky1508]

Is their any thing leaving from their board going out has a sub!

Nothing!!!!! All very strange. Can't seem to find a problem anywhere apart from the fact that L1 spikes but only reading 6 amps at the other end.

 

[GlenTavener]

Lets hope they are not hosting some adverse horticultural operation in a loft or other unexpected place. The amount is massive.

 

[CACJL]

Maybe there is an appliance they have overlooked, say a heater in a loft for frost protection. During a period when the meter seems to be running briskly or use a clamp meter, turn off the MCBs gradually one by one until the consumption falls.

 

[buzzlightyear]

draw a plan and show us the out lay of the buildings from main to outer , they have not got a swimming pool by any chance .

 

[buzzlightyear]

the best get a thermal image camera for this job.

 

[Midwest]

Put a meter in for the cottage, and make them pay for their leccy. That'll stop 'em farting in church. Sorry can't be helpful

 

[UKMeterman]

Hi,
The cost of a weeks or a months hire from inlec of an energy monitor would be about £105 a week. I would explain to the client the costs of sub metering, any meter used for billing the cottage needs to be of a certified design, but other sub meters can be anything you like. Have chat with these people and explain to the client how sub meterting could save them money (and make you more profit) MID Certified Meters | Rayleigh Instruments - http://www.rayleigh.com/kwh-and-multifunction-mid-certified-meters.html

The cost of decent meters is now dirt cheap Rayleigh Instruments RI-122-100-P Three Phase MID Certified 100A Meter - https://www.rapidonline.com/rayleigh-instruments-ri-122-100-p-three-phase-mid-certified-100a-meter-561967

Rayleigh Instruments RI-7X Series Single Phase MID Certified Meters | Rapid Online - https://www.rapidonline.com/rayleigh-instruments-ri-7x-series-single-phase-mid-certified-meters-561966

 

[CACJL]

Is there a hidden Cannabis enterprise on your property?

 

[Wilko]

Nothing!!!!! All very strange. Can't seem to find a problem anywhere apart from the fact that L1 spikes but only reading 6 amps at the other end.

Hi - well if 30A went in and 6A came out, there is 24A dripping away in between ... I would turn all circuits off that the house DB and see what's going down their sub main. An IR test of the sub main to the house perhaps?

 

[alasdairp]

Meter readings all seem to coincide. Found out it's an actual meter reading every 6 months so every other quarter is an estimate based on last reading. Just checked the last two actual readings and in the 6 months usage was 28187 KWh. Think it's at 13p so that would work out at £3664. Please correct me if I'm wrong. Any other ideas welcome.

27184/180/24 = 6.5 kW continuous =6500/230=28 A continuous on a single phase. Having read all the posts, I would be very suspicious of the meter. Also I would put a clamp ammeter around the incoming 3 phase plus neutral cable and check that the current balance is zero (or very near zero). Many early 3 core XPLE cables with combined N&E armouring have been found to rust through leaving any out of balance N current (which you will have here) to find its way back via the other (ground) paths. That can interfere with the 3-phase meter accuracy. I and the DNOs/RECs have found this at many sites - at one commercial site I once found 330 A entirely returning via earthed building steel and metal water and gas pipes and not along the cable as it should have been. Everything was working fine at that site - I was there to investigate wobbling VDU computer displays - caused by elevated 50 Hz magnetic fields due to the currents in the structural steelwork. I am not saying the above will be the answer - but certainly worth checking for.

 

[sparky1508]

Done IR on house sub main as all morning had a consistent 7 amps on incoming L3 with a consistent 4.6 amps on the outgoing L3 to house.L1 and L2 both negligible at near 0 amps.
Checked all 28 circuits in house DB for current flow but nothing with a significant flow. Getting frustrated at this point. About 2pm the couple arrive home and just out of curiosity thought I'd see what happens as I knew the cottage was single phase so just stuck the clamp meter back on and started getting some high reading on L1 incoming in the plant room just before the meter and the light was ticking away. The readings were sit at 10 amps for a bit ten shoot up to 25 and 37 sit for a few seconds and drop again and then continue with the same kind of sequence. Went to the cottage and checked the out going loads but only had 6 amps in the cooker circuit as she was cooking. Nothing else pulling anything much. So still left a bit fuddled, thinking now either the thermal imaging camera which is a good idea but thinking i could possibly get a better result by fitting those energy meters suggested by meterman. They look quite affordable so will make a suggestion to my clients.

 

[buzzlightyear]

now either the thermal imaging camera

and one of those

keep digging you find it.

 

[satori]

Well the couple in the cottage have just got back and now the supply to the cottage is pulling anywhere between 10 and 37 amps sometimes sitting at a steady 17 but also sits at around 26. Something going on there. More detective work needed.

Is the supply to the cottage undersized? If there's significant volt drop between DB and cottage then, V=IR, if volts go down amps must go up.

 

[CACJL]

Is the supply to the cottage undersized? If there's significant volt drop between DB and cottage then, V=IR, if volts go down amps must go up.

The only type of device where the current increases when the voltage is reduced (constant power) is one that is powered through Switch Mode Power Supply. I am an ex-designer of Switch Mode Power supplies.

 

[sparky1508]

This is the main board in the plant room. 1L1,2,3 is 3 phase to main house, 2L1 is single phase to cottage.
2L2 is single phase to barn/plant room.
2L3 is single phase to another barn.
3L1,2,3 is 3 phase out but not labelled up so need to speak to the owners about this one. It was completely inactive the whole time I was there. 5L3 is single phase to stable. All pretty much inactive apart from the ones I mentioned.

 

[sparky1508]

This is the main board in the plant room. 1L1,2,3 is 3 phase to main house, 2L1 is single phase to cottage.
2L2 is single phase to barn/plant room.
2L3 is single phase to another barn.
3L1,2,3 is 3 phase out but not labelled up so need to speak to the owners about this one. It was completely inactive the whole time I was there. 5L2 I think it was is single phase to stable. All pretty much inactive apart from the ones I mentioned.

 

[sparky1508]

Here

 

[UKMeterman]

Ok,
Check the suppliers meter,and can we have a photo. If it is uusing CTs check the phasing.

Note if you do use the meters I suggested their registers increase regardless of the power flow direction.

 

[Davisonp]

I have had a problem where trying to find an earth leakage and I found when clamping round the earth I was reading between 2 Amps and 5 amps, even with the main switch to the property turned off . To cut a long story short the voltage was about 2 milliamps finding it’s way through my clients house back to the supply, but the clamp meter does not care about voltage just amps.

I have also had problems at a site where the supply voltage to a property was low on two phases but as low as 188 volts on the third phase. It may be worth considering ruling voltage problems out.

 

[a-z electrics]

At that monthly cost I would suggest buying an energy monitor for each of the three CUs.. they only about £30 each. And you /client can use them afterwards too.
I assume RCDs are fitted to each CU? This would trip if any earth leakage. If fitted, I would suspect faulty meter. Get elec company involved..

 

[a-z electrics]

To cut a long story short the voltage was about 2 milliamps finding it’s way through my clients house back to the supply, but the clamp meter does not care aboutvoltage just amps.

Do you mean millivolts?

 

[Pete999]

To cut a long story short the voltage was about 2 milliamps finding it’s way through my clients house back to the supply, but the clamp meter does not care aboutvoltage just amps.

Do you mean millivolts?

 

[Davisonp]

To cut a long story short the voltage was about 2 milliamps finding it’s way through my clients house back to the supply, but the clamp meter does not care aboutvoltage just amps.

Do you mean millivolts?

Yes, My mistake.

 

[davesparks]

Is the supply to the cottage undersized? If there's significant volt drop between DB and cottage then, V=IR, if volts go down amps must go up.

No, the current must reduce as the voltage is reduced, otherwise at zero volts the current would be infinite!

 

[Lucien Nunes]

Not necessarily true. Over the range of voltage at which they will operate correctly, some loads, mostly SMPSUs, have negative dynamic resistance, because they consume approximately constant power regardless of voltage. Current is therefore approximately inversely proportional to voltage. However, outside of the operational range, the current usually falls to zero as the device shuts down. There are other loads that behave like constant power loads integrated over a longer period of time, mainly thermostatically controlled heating. Increasing the voltage drop of a heating circuit, such that the heat dissipated by the cable causing the drop doesn't heat the target space, will require the heater to be on for a greater duty cycle to maintain the set temperature as its heat output will have decreased. But the consumption at the meter won't have decreased by the same amount, so the energy consumption to maintain the temperature will increase by the amount lost through voltage drop.

A moment's thought suggests that energy loss through voltage drop is not the culprit here though. We have been talking about 24/7 loads in the order of ten kilowatts in order to run up these bills, and it would be a surprise if there was that much capacity of SMPSU on the whole site. Then, to make the bill so much higher, the voltage drop would have to be a significant fraction of the supply voltage, for the wastage to have a significant efffect on the bill. There would be all sorts of other symptoms things randomly shutting down, filament lamps that glow dimly and almost go out when you turn the microwave on, which would take 2 hours to boil a cup of water.

Look elsewhere...

 

[DPG]

They haven't got an electrically powered cinema organ blower in the bungalow have they?

 

[davesparks]

Not necessarily true. Over the range of voltage at which they will operate correctly, some loads, mostly SMPSUs, have negative dynamic resistance, because they consume approximately constant power regardless of voltage. Current is therefore approximately inversely proportional to voltage. However, outside of the operational range, the current usually falls to zero as the device shuts down. There are other loads that behave like constant power loads integrated over a longer period of time, mainly thermostatically controlled heating. Increasing the voltage drop of a heating circuit, such that the heat dissipated by the cable causing the drop doesn't heat the target space, will require the heater to be on for a greater duty cycle to maintain the set temperature as its heat output will have decreased. But the consumption at the meter won't have decreased by the same amount, so the energy consumption to maintain the temperature will increase by the amount lost through voltage drop.

Yes it was a bit of a broad sweeping statement on my part, and I think in the context of the thread it was valid despite the exceptions.

Whilst the heater would behave as I find it was constant power, the current in the circuit would still be reduced in proportion to the reduction in voltage.

 

[davesparks]

On the job now. Reading a constant 7.6 amps in L3 incoming on main board. This L3 also had a constant 4.8 amps to main house. Any ideas

How are you measuring this, are the two readings averaged over a period of time or are they instantaneous readings?
If instantaneous then unless the two readings were taken at the same instant then they can't be related to each other.

 

[davesparks]

Just been in and the only circuit pulling any significant current is the cooker at 6.6 amps. Don't know why it kept spiking but it's only since they got home. L1 was pretty much inactive until try arrived then starts spiking at 36 amps at times.

Then clearly something has been switched on which draws that current.
What times does it spike at, are they regular intervals or apparently random, what is the duration of the spike?
Is the spike always of the same magnitude?

 

[buzzlightyear]

 

[buzzlightyear]

he can sing this song when he looking for it!

 

[DPG]

It's a mythtery!

 

[Squid]

With the amount of time the OP is spending on site he'll be singing this in the van on the way home,