Investigation on massive electricity bills

[sparky1508]

Hi all,
This morning I visited a new client who needs me to find out why there bills are so high.
At the moment I can only give a quick rundown of the installation as it was just a general chit chat about the issue. I will be going back to do some proper investigation in a week or so.
This is an old manor farm with the main house having been extended along with an attached barn conversion which is their main living space. 3 story's including the loft conversion so quite a considerable space. They have a 3 bed cottage ( Detached )on the land along with stables a plant room and a wooden barn converted for parties in an L shape. So they called me because they are getting extremely high bills. The 2 that I saw was 1 for last 3 months and 1 for the previous 3 months. The latter was for £4100 and the other was £2700. I did get a quick look at a couple others and they were similar costs ranging anywhere in between.
Firstly can anyone say whether this is normal for a house of this size when they have assured me that they don't use the emersion heaters as they have 2 big oil boilers in the plant room.
Wet underfloor in the new half and the barn end and radiators in the old part of the house.
Also my first thoughts are that I need to familiarise myself with the wiring of the entire installation so I can eliminate circuits one by one. Any advice is welcome as always.

 

[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.