solar metering faults

[justoldmikey]

Hi I have long retired as an electrician,so all this solar is over my head.I had some 20 panels fitted to my roof in January this year,so a 3.8 KWT system.I was told that in daylight hours me and my old dutch would be able to use the electricity generated by the panels,that is using one bit of electrical equipment at a time i/e best practice.what is not used goes out to the Nat Grid and we are payed FIT.Is that OK so far?
Now here is the problem,in 9 months The generated electricity is good and FIT is high,but the utility company tell me solar has made no difference to my bill or usage.I done a small test myself.( With nothing switched on in the house accept the fridge and freezer,and under their thermostat were not running.on a clear sunny day,I plug in the hoover, current/electricity flows and is being supplied from the Nat Grid I also tried the same to boil a kettle of water the same happens.Iv had the utility meter tested and the electricity company has said there is no fault with their meter.The installation company recognize there is problem.The meter for the solar is an Elster and what I can gather is recording OK.The MCS is looking at the problem as well.
For me it looks like all that is generated from the solar is going straight out to the Nat Grid,and not supplying the house its self
If there is any one out there who would kindly point me to the likely cause of the problem/fault(so i don't look a complete idiot) when I have to talk to the installation company or when I get a electrician to repair the fault.Any help or advice will be appreciated

 

[SolarCity]

Are you sure the PV system is connected correctly? It sounds like it may be connected to the 'supply' side of the incoming supply meter. Therefore all generated power is still registering on that meter.

I doubt it would be this simple though as your installation company or the DNO/supplier would have picked up on this by now.

 

[wersolaruk]

The meter might not have reverse energy detection built in which could mean the incoming supply meter is not stopping when there is enough energy from your pv to run your house. I may have got the wrong end of the stick here though?

 

[7029 dave]

I would call your energy supplier, the meter you have may not be new generation compatible?.

 

[Earthstore]

Could you post a pic of where your PV is connected into your system, also a pic of your supply meter may be good too.

 

[Gavin A]

3 options

1 - the installer wrongly cut the tails between cut out and suppliers meter and installed to a henley block at that point, so the solar generation is on the wrong side of the suppliers meter to impact on consumption

2 - Your suppliers meter has an antitamper setting so it clocks up in both directions - if you actually do use 50% of generation then this wouldn't show up over the year, but should do in summer when. The most common meter for having this problem is a Siemens meter, blue and grey, I forget the model, but others can do this. Test it out by turning the main switch off at the CU in bright sunlight and seeing if the suppliers meter is still clocking up when it's dyefinitely exporting.

3 - You've left your immersion heater switched on or something similar that accounts for an actual increase in electricity consumption.

 

[justoldmikey]

Thanks the problem is the installation company blame the utility company who in tern say their meter is working OK.Me Im just piggy in the middle.But thank you for your help, the connection is something I think is wrong

 

[justoldmikey]

Thanks for the reply,the energy supplier say that the meter they use is standard and is compatible

 

[justoldmikey]

1 very interesting but I cannot get installer to come back to check,and haveing to get MCS to chase them,but for me I think that could be the problem.
2 The suppler says that is the standard meter they use (Actarist)
3 I wish it was just that, would save me a lot of time.But thank you for your help

 

[SolarCity]

Have the installer actually been back to site to check?

You really need to post a picture of how the meters are connected. We could then rule out the most likely problem; that the PV system has been connected incorrectly.

 

[justoldmikey]

Thank you I don't know if these ar OK the connection is on thr far right

 

[justoldmikey]

Have the installer actually been back to site to check?

You really need to post a picture of how the meters are connected. We could then rule out the most likely problem; that the PV system has been connected incorrectly.

 

[justoldmikey]

Hi thanks for that, M C S is currently chasing the installer company.Sorry the photos are the best I can do as I find it difficult to get down to the floor level to do anything,But thank you for the reply I now know that with the wonderful respounce I have had the fault in this system is not my imagination and now I wont be fobed off by the installation company

 

[SolarCity]

Hard to tell from the pictures. Is the PV system connected directly to the consumer unit? It isn't that cable connected to the main switch is it?

 

[Gavin A]

View attachment 21128View attachment 21129View attachment 21130
Thank you I don't know if these ar OK the connection is on thr far right

Am I interpreting that right, that the solar is sharing with the main incoming tails on the supply side of the main breaker?

I suppose that's one way to avoid the issue of RCD trips on a split RCD board, but it looks to mean that there's no overload protection... probably not actually an issue in reality as it's a current limited device, but overload protection is specified in G83 regs if I remember right.

So anyway, back to your problem... I'm not aware of issues with that meter, and the solar is connected to the correct side of the meters, so I'd think the most likely cause is either a fault somewhere in your house / appliances that's resulted in an increase in consumption, or you or someone in the house has been doing something like turning the immersion heater on during the day to try to make use of the solar, or the immersion has just been left switched on or something like that resulting in an actual increase in consumption levels.

To try to work it out, I'd probably put a henlye block in to split the tails to bring the solar in at that point, then install a standard clip on monitoring device such as a current cost unit to monitor your actual consumption - maybe even use the optical reader to monitor both meters at the same time, then work out what's actually going on.

 

[Gavin A]

Hi thanks for that, M C S is currently chasing the installer company.Sorry the photos are the best I can do as I find it difficult to get down to the floor level to do anything,But thank you for the reply I now know that with the wonderful respounce I have had the fault in this system is not my imagination and now I wont be fobed off by the installation company

actually, it doesn't look like a fault in the installation to me from those photos.

 

[Worcester]

Nope, doesn't look like a fault in the installtion of the PV causing that problem, however as you say no overload protection on the connection as it looks as it goes to the tails on the main incoming switch. Not the best practice..

2.3.5 a.c. Cable Protection
Protection for the cable from the inverter(s) must be provided at the distribution board. This protective measure shall be specified and installed in accordance with the requirements of BS 7671. In very many cases the current limiting nature of the PV array and inverter(s) omits the requirements for overload protection and therefore the designer only need to consider fault current protection. The protection afforded at the origin of the circuit (the distribution board) in accordance with BS 7671, means there is no requirement for additional overcurrent protection to be installed at the inverter end of the a.c. installation.

So although no overcurrent protection exists, without an MCB it is relying on the main fuse to provide the fault protection (BS7671: 411.3.2.1) which I doubt it would meet (0.4sec), else we'd not need to put MCB's in at all

 

[Matt_M]

Is the cable run from the inverter to the fuse box very long? If it is; it could be an issue with Volt drop/incorrectly sized cable

 

[justoldmikey]

Thanks for that,I thought something along that line,i did think it may be some high resistance in the wiring.the MCS without checking has said nothing is wrong with the system.So in the summer(as I live in the north on Scotland)I will get an independent registered sparks out to look at the whole system.But once again thank you for your incite to this problem

 

[Noddy67]

where abouts are you in the UK. If you're very local to St Albans I wouldn't mind having a look - pictures are difficult to check.

 

[whinmoor]

where abouts are you in the UK. If you're very local to St Albans I wouldn't mind having a look - pictures are difficult to check.

I think he's in the Scottish Highlands!! mg_smile:

 

[justoldmikey]

Your a gentleman sir, thank you for that.Problem is I live on the north east coast of Scotland,but again thank you

 

[justoldmikey]

Thats correct not much sun ether at the moment,thank you