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bcs009
Rank 2
September 18, 2022
Solved

Why is the same amount of energy drawn from the grid with my solar turned on or off? Could my SMETS1 meter or PV wiring be faulty?

  • September 18, 2022
  • 16 replies
  • 491 views

I have a very specific issue and I’ve been reading forums looking for a solution for weeks now. Please someone help me where to even start.?

 

Same amount of power drawn from grid with Solar turned on or turned off. BUT if the usage is less in the house than the generated energy by my panels, drawing from the grid stops and it is actually exporting back to the grid. I have a smets1 meter.

 

I did a test the other day. Turned off everything in the house except one appliance which draws 1 KWh. It was sunny so my panels were generating constant 0.5 KWh. I have a Netthings energy monitor hooked up to the Consumer Unit. This showed me that I am actually using 0.5 KWh which is correct as half of my energy was satisfied by my solars and half drawn from the grid. BUT after one hour the smets1 meter outside went up by 1 KW meaning that it completely ignored the solars.

 

I did another test. Same thing, only one appliance using constant 1KWh. Solars turned off. Got the same results - 1 KW up on the smets1 meter after one hour.

 

In another test I did turn off everything in the house except solar. It was generating constant roughly 0.5 KWh. In this case the smets1 stopped drawing and import number stayed where it was before. I did check the export and it went up by around 0.5KW after an hour.

 

 

So clearly what the smets1 meter is doing:

 

If the solar generation is higher than the usage in the house. Import from the grid stops, and export starts so it is aware in which direction current flows.

 

If the solar generation is less than the usage in the house, the smets1 completely ignores my generated energy and takes everything from the grid. What is strange is that my Netthings energy monitor which again connected to the Consumer Unit is aware of the solar and shows me the correct KWh usage and offsetting the number by the generated solar energy.

 

Is this a wiring issue or smart meter issue?

Best answer by M.isterW

It all looks okay. I can't see anything obviously wrong.

 

The black box attached to the cable above the main switch is the CT clamp for your energy monitor. This seems to be in the right place although I can't see if it's the right way round. The placement means it should show electricity flowing to and from the grid.

 

If the problem was high voltage (and 244v is within the allowable range) I would expect your inverter to shut off and/or show an error.

 

Can you move the CT clamp? Could you put it on the meter tail so you're measuring exactly what's going through the meter?

 

 

Thank you all!

The CT Clamp was loose hence my energy monitor was recording less energy.

The daily difference in KW between my energy monitor and the meter was roughly the same as my solars were generating in a day.

Thats why I was so confused. I did tighten the clamp with a zip tie (the bit where you can clip the clamp together was worn out, its visible on the pics if you look closer) and its all good.

Smart monitor and meter matching almost exactly now.

Thanks again!

16 replies

M.isterW
Rank 6
M.isterW
Rank 6
September 18, 2022

Do you have a wiring diagram that shows how your solar PV is connected? Or some photos showing all the wiring?

1992 4 bed detached house. Solar PV + battery, Zappi EV charger, Mitsubishi Ecodan ASHP and i-life2 fan assisted radiators.... No gas 😊
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Rank 2
bcs009Author
Rank 2
September 18, 2022

Here it is. This diagram looks ok to me. I am not and electrician so I have no idea if it was indeed wired this way though.

 

 

M.isterW
Rank 6
M.isterW
Rank 6
September 18, 2022

It looks like everything is wired in correctly but I can't see how the meter can be doing what you describe.

 

Does your energy monitor have a CT clamp? Can you check what's coming into the meter?

1992 4 bed detached house. Solar PV + battery, Zappi EV charger, Mitsubishi Ecodan ASHP and i-life2 fan assisted radiators.... No gas 😊
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Rank 2
bcs009Author
Rank 2
September 18, 2022

Inside the house next to the door there is the consumer unit, the Netthings smart monitor and separately a box for the distribution board and total generation meter. All the cables hide behind these so I have no idea if there is a CT clamp and what is exactly those grey cables going into the meter come from...

B
Rank 2
bcs009Author
Rank 2
September 18, 2022

This might be a silly question but can it be that those grey wires coming from the PV distribution board instead of the consumer unit?

So that way the consumer unit would be using (X minus solar generated) and then solar generation from the PV distribution gets added to that (total would be X in that case) and that is what’s then passed onto the smets1 meter.?

This might be complete nonsense but I can’t think of anything else except faulty smets1 meter.

M.isterW
Rank 6
M.isterW
Rank 6
September 18, 2022

I wonder if your energy monitor isn't recording what you think. It should have a CT clamp around whichever cable it's measuring and that could be round the wrong cable.

 

I can't think of anything else that could be causing what you're seeing.

1992 4 bed detached house. Solar PV + battery, Zappi EV charger, Mitsubishi Ecodan ASHP and i-life2 fan assisted radiators.... No gas 😊
M.isterW
Rank 6
M.isterW
Rank 6
September 18, 2022

Could you post a picture of your consumer unit(s) and the cabling around them?

1992 4 bed detached house. Solar PV + battery, Zappi EV charger, Mitsubishi Ecodan ASHP and i-life2 fan assisted radiators.... No gas 😊
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Rank 2
bcs009Author
Rank 2
September 18, 2022

Thanks so much for replying again!

I will take some pics tomorrow!

B
Rank 2
bcs009Author
Rank 2
September 19, 2022

The Netthings energy monitor is an internal thing. It only connects (via wires) to the consumer unit and shows me gas and electricity usage in real time.

It does not have any connection to the smets1. It is not an IHD. So I guess my wiring does not even have CT clamp.?

 

All the wiring is hidden and I don’t want to start messing around taking off the face plate of the consumer unit etc. I am not sure if this is helpful at all but here is the pictures.

 

 

Thanks in advance for your reply!

Emmanuelle_OVO
Retired Moderator
Emmanuelle_OVO
Retired Moderator
September 20, 2022

Hey @bcs009,

 

Welcome to the OVO Online Community.

 

It’s great to see you’ve already met our community member @M.isterW whose given some great advice. I’m wondering if @ArundaleP, @sylm_2000 and @PeterR1947 have any insight here? 

 

I’d advise contacting the installer directly and seeing if they’ve encountered this issue before. 

 

You may have already seen these pages as you mentioned you’ve been checking forums for a few weeks, but if not we have some similar threads and a great guide which may be helpful: 

 

 

Keep us posted with how you get on! 

Renewable Energy? Big Fan.
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