Three Phase Meter installed and Kwh use soars

roofbarman

In July 2021 we had UKPN run extra cabling in to allow us to replace our single phase meter with a three phase meter. The property continued to only use a single phase all the way through to 16th March 2022; only after that date did we trigger use of the other two phases. What's strange (and we have all the readings to prove it), is our kwh usage increased dramatically (circa 9,500kwh annual to 21,000 kwh annual) from the moment the new cabling and meter was installed. Nothing has changed inside the house- we have had the meter checked for accuracy, as well as all our internal electrical items, including our NIBE GSHP - nothing is awry. The technician who checked the meter reading confessed to not being three phase trained, but he said it was reading accurately.  In a recent discussion with my supplier I learnt three phase meters give a 6 digit read out, whereas ours is only 5 digits - this confused the person on the other end of the phone. I did some searching on-line and there is reference to meters being compatible or otherwise. I am booked in to get the meter changed to a smart meter (the current one says it's a smart meter, but Eon can't read it remotely) but am curious if anyone knows if my problem could have been created by the wrong type of three phase meter being installed.  Must confess its driving me a little insane, my May bill was £758 for the month, so need to get it sorted before winter comes around. Any thoughts or insight would be appreciated.    

MattMattMattUK

roofbarman said:

In July 2021 we had UKPN run extra cabling in to allow us to replace our single phase meter with a three phase meter. The property continued to only use a single phase all the way through to 16th March 2022; only after that date did we trigger use of the other two phases. What's strange (and we have all the readings to prove it), is our kwh usage increased dramatically (circa 9,500kwh annual to 21,000 kwh annual) from the moment the new cabling and meter was installed. Nothing has changed inside the house- we have had the meter checked for accuracy, as well as all our internal electrical items, including our NIBE GSHP - nothing is awry. The technician who checked the meter reading confessed to not being three phase trained, but he said it was reading accurately.  In a recent discussion with my supplier I learnt three phase meters give a 6 digit read out, whereas ours is only 5 digits - this confused the person on the other end of the phone. I did some searching on-line and there is reference to meters being compatible or otherwise. I am booked in to get the meter changed to a smart meter (the current one says it's a smart meter, but Eon can't read it remotely) but am curious if anyone knows if my problem could have been created by the wrong type of three phase meter being installed.  Must confess its driving me a little insane, my May bill was £758 for the month, so need to get it sorted before winter comes around. Any thoughts or insight would be appreciated.    

I don't know the specifics of three phase meters, but I am wondering if it could be something to do with how you are drawing from the phases and if they are balanced? Is there any additional kit connected to the three phase supply that could be drawing that kind of power and if you turn it all off does the usage drop proportionately, effectively the meter sanity test, but I do not know if being on three phased impacts it in any way. 

QrizB

roofbarman said:

Any thoughts or insight would be appreciated.   

It's quite possible that your old meter was under-reading, but that meter is long gone so we'll never know.

Mobtr

Can you post a reading on here? It could be you’re reading incorrectly. What is the whole reading? 

roofbarman

Thank you for commenting. We take a photo to read the meter each day and it's a digital reading, so just reading off the numbers. Following is a table of the kwh's used each month from August 2018. We have a GSHP and the compressor stopped working in July 2020. When that happens an immersion kicks in, hence the uptick in kwh - we were slow in identifying the issue and things were delayed during pandemic. It was fixed in November 2020 by installing a new soft start, so all good until 6th July 2021. We did not take readings initially as it states its a smart meter and we thought it was being read by our supplier (who went bust), who preceded Eon Next. So the September 2021 reading is for 3 months - you cannot match it against the 2020 readings, but look at usage in 2019 and 2018 - similar, compare January - May 2022 readings versus same months in 2019, 2020 and 2021

	TOTAL USAGE
	2018	2019	2020	2021	2022
January		1,143	833	833	2,960
February		832	776	599	2,436
March		616	758	482	2,281
April		687	806	474	2,525
May		662	652	371	1,988
June		644	769	375
July		590	1,549	-
August	657	452	1,087	-
September	576	608	1,461	4,300
October	676	821	1,954	1,892
November	853	964	2,119	2,032
December	958	1,052	831	2,330
Total	3,720	9,071	13,595	13,688	12,190

QrizB

Just looking at the numbers, it's almost as though your GSHP has failed again and you're using direct electric heat.

But you say your GSHP has been checked over by a technician.

Does the heat pump has its own separate electric meter, many do in order to qualify for RHI?

lohr500

That is a very good observation from QrizB. I would definitely get the GSHP checked over again.

markin

Take hourly reading for 3hrs then shut off the immersion, Then readings for 3hrs, Then repeat with the GSHP off.

roofbarman

Thank you for the feedback. We focused on the GSHP as the problem as we agree the readings were "as if" the compressor had failed and the immersion was kicking in. Even though we could hear the compressor working, we still changed the soft start as we were told this bit of kit did more than just fire up the compressor. Unfortunately the new soft start (£350+) made no difference. We had three engineers look at the GSHP - two were contractors (£250+each) and the third was NIBE (£510) themselves. The first contractor came up with the good idea of us putting a meter on the power to the GSHP, which we did. We took readings every day for the GSHP and the house and when NIBE came they inserted an Sd Card in to the GSHP and we left it for a month to take readings. Their engineers looked at the months data and the units efficiency and they said even though it's 10 years old, it's running perfectly. When asked why its using more in kwh's by itself versus what the entire house used to use on its own, they said that's a mystery, but bear in mind your house usage has gone up by more than the increase in the GSHP! I see the comment that references the old meter may have been wrong and we've benefited from that for almost 20 years, but I am afraid that does not fly as we are a four bedroom house, built 10 years ago, with modern insulation and there is no way we could be using what will amount to 30,000kwh in 2022. I have even had a crack at UKPN as when they put in the new cable, they could not take out the old cable back to source (road would have needed digging up), so they buried the live cable a metre under the ground and left it. I approached them to say that must be causing the uplift - their response was entirely logical in that everything up to the meter is their responsibility but from the meter to the house is ours. I've even turned everything off in the house and checked the meter to see if I am paying for my neighbours electricity! Eon Next are coming back to install a smart meter and I am hoping a change of meter might do the trick. Meanwhile I am getting solar panels installed to see if I can stop haemorrhaging cash each month. 

markin

Well what is the daily usage for the GSHP and the house, The GSHP should be very low for just hot water, how many people and showers a day? And the hot water temperature?

doodling

Hi,

The data suggests that the meter change has not affected your measured consumption - that changed in July / September 2021 rather than March this year when the meter was changed.

To burn through that much electricity then something is getting hot - May's usage is equivalent to a 2.7kW continuous load - that is massively more than you would expect to use for just hot water, cooking and other uses, even if you were using the immersion heater rather than the GSHP for hot water (as you can see from the consumption from the time you know the GSHP was non-functional).

I suspect that either the GSHP is broken in a way that is just consuming energy without doing anything useful (in which case it will be getting seriously hot when "on") or you have another load turned on somewhere that has been forgotten about (heater in shed, hot tub, electric car, electric patio heaters, hot tap left turned on, cannabis farm in loft, next door neighbour's entire house, etc.).

On the plus side, finding a load that size is pretty easy - keep your eyes on the meter and when the little LED starts flashing like mad trip the breakers one by one until you find the culprit.  If there really isn't anything else it can be then maybe you could turn off the GSHP for a day and see what difference that makes to your daily consumption.