Is it even possible to monitor my solar pv installation properly or am I scuppered?

[very]

Hello everyone, this is my first post. I'm not an electrician, but I'm really in need of one, it seems! I have had a 4KW solar array installed to supply my home. It's ground mounted in the field next to our garden so is quite some distance from the house. The installer has put the inverter, the isolators, the generation meter etc in a wooden stable building in the field, which already had a (rarely used) electricity supply. As I understand it, the generated electricity goes back down the cabling which already existed to supply the stables and ends up in our garage where the consumer unit is. The stables circuit was wired up separately to the main consumer unit and has its own switch box thingy (is this a "sub-main"? not sure).

Anyway.

I found, as have others, that my British Gas energy monitor went nuts after the solar was switched on and the flow went bi-directional. I could no longer see my actual household consumption, only net flow without knowing the direction, and I had to use the lightbulb test, flicking a switch to work out whether I was exporting or importing. However, since I have two of these monitors, I was keen to attempt some of the solutions I found on this forum, such as using a Henley Block, or clamping around two wires at once. I printed them off and showed them to the installing electrician. Unfortunately he did not get it. At all. He got completely muddled over the whole concept and didn't seem able to implement the solutions I had printed out. He tried to put the clamps around some random cables, failed to achieve a result, and then told me "it's not a science, all this" :confused5: and gave up completely and left.

I now have no real time monitoring of either my generation or my consumption and so no way to use my electricity effectively. My installer has promised me a remote generation monitor but hasn't suggested which one yet. I've been looking at the Wattson solar plus but I'm unsure whether this can work, given the 50 metre distance between the inverter and the main consumer unit. I may be wrong, but all of the wiring diagrams seem to require them to be in closer proximity than this.

Can anyone tell me whether this is possible, please?
Failing that, is it still possible to find a monitoring solution using my two British gas energy monitors? I want to know real time electricity production and real time gross household consumption too.

I'd really appreciate any help from anyone who can shed some light on my predicament! Thank you.

 

[moggy1968]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

Wattsons pretty rubbish in my experience
what inverter do you have

 

[whinmoor]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

Can you tell us what brand and model of inverter has been fitted? How far is it from your house?

 

[Gavin A]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

can you post a picture of the consumer unit / point where the cable feeding the stable is connected to?

yes it is possible to sort this out, it's fairly easy and I reckon most of us on here do it as standard on most jobs.

basically done like this

consumer unit
^
tails (1)
^
henley block >tails(2)>meter>tails>mini consumer unit>SWA cable>isolator(3)>inverter
^
tails
^
suppliers meter
^
^
incoming mains


(1) clamp meter to monitor consumption
(2) clamp meter to monitor generation
(3) if there are also distribution circuits for loads in the barn, then a seperate mini-consumer unit must be installed in the barn at this point to prevent potential overload of those circuits as the overload protection from the consumer unit is compromised by the PV generation input.

 

[very]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

Thanks for the speedy responses. The inverter is a Fronius IG TL 4.0 I think. The stable is probably >50 metres from the house and garage. I can certainly take and attempt to post pics tomorrow. Am feeling a bit guilty about castigating my electrician as he was a lovely chap, but he just couldn't sort this out for me and I think he just didn't understand the problem at all, so I got frustrated.

Anyone know of a site where I can upload a couple of pics of my electrical set up?

 

[Gavin A]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

Anyone know of a site where I can upload a couple of pics of my electrical set up?

this site. just use the attachments bit when posting, and you can upload them from your PC. need to use the go advanced button.

 

[very]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

Ah yes. Thank you. :blush5:

 

[whinmoor]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

Thanks for the speedy responses. The inverter is a Fronius IG TL 4.0 I think. The stable is probably >50 metres from the house and garage. I can certainly take and attempt to post pics tomorrow. Am feeling a bit guilty about castigating my electrician as he was a lovely chap, but he just couldn't sort this out for me and I think he just didn't understand the problem at all, so I got frustrated.

Anyone know of a site where I can upload a couple of pics of my electrical set up?

OK - sounds like you've got a suitable, well-matched inverter. It will be interesting to see your snaps.

 

[very]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

Here's the layout in the stable with the inverter etc. I'll take one of the consumer unit in the garage tomorrow and upload that.

 

[moggy1968]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

oh dear!
whats happened to the proper labels, those don't comply and their should be some on the inverter and the DC cable.
Why 2 consumer units? As far as I can see the left hand one feeds the consumer marked AC isloator which then feeds a proper isolator which is rather pointless. Or has he reverse wired the one marked isolator in some sort of missguided attempt to provide RCD protection for the cable to the house? It looks like it comes from a shared RCD which is a nono. The wiring is a shambles. The supply cable to your house looks too small for a run of 50m.

check your meter is recording production as expected.

It's not looking good so far TBH

In his favour, finding an energy monitoring solution like you want thats half decent is tricky. I believe most clamp type monitors struggle with 2 way flow.

 

[very]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

Thank you for responding, and my apologies, but the only thing I really understood from your post is "it's not looking good so far".

Yikes.

This is the same person who supplied the electrical safety certificate of course. Should I now be worried about that? Should I be getting another electrician out with better knowledge of solar array systems and wiring?

 

[very]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

Re: the consumer units, I think the one on the left is what was already in the stable for its original electricity supply.

 

[Gavin A]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

actually moggy, I reckon he might have got it right with the 2 garage units thing - one for solar, one for circuits in the barn, although I'm not really sure they've done it quite how we would have.

I'd have been expecting to see a reasonably hefty SWA cable somewhere though, unless the 6mm(?) t&e cable I can see is the incoming cable and it's been run through a metal pipe / conduit or something.

 

[moggy1968]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

I think the swa is coming in from right of the DC isolator for the DC. I was wondering about the AC side, maybe, as you say, it goes into conduit of some kind. It looked to me, but may just be the way it looks, that there is a cable running from the garage unit to the consumer unit marked AC isolator. So the solar system is being run from the existing garage unit, wrongly sharing an RCD and pointlessly using 2 MCBs, migh be wrong of course. I had one like this recently but it was just to make it look smart, the cable was actually just passing through the first CU.

 

[series530]

Re: Is it even possible to monitor my solar pv installation properly or am I scuppere

You can, in principle, monitor the electric generation by connecting something like an Optismart to the optical pulse read out on the PV meter. The problem will be getting that output back to a receiver if it is some distance from the house. If you are really serious you could connect an Envir monitor locally in the out building and attach a smart bridge to it. You will then need to run an ethernet cable from the bridge to a router and you can then montor usage on the web. Alternatively, mount the Envir in the outbuilding as before and buy a cheap wireless CMOS camera at Maplin. Point this at the EnviR monitor and when you want to monitor production simply view the camera using a PC.

Another approach is to buy another PV meter and install this inline with the PV feed (the Elster AC100 is cheap as chips) and then buy the EnviR montor and an optismart (£50 or so for the two units). Put both near the consumer unit in the house and the transmission range will be fine.

Measuring the incoming power is harder because the current clamps are generally hopeless. They give an indication but nothing more.

On my system I have an Oprismart/EnviR on the PV meter and this is accurate to within about 1%. I have another Optismart ion the consumer unit but it doesn't register when the system is exporting. It also wont work if your consumer unit is an older system without an optical output.