Problems with a new solar install

[Earthstore]

Oh my giddy Aunt, what a shambles, not too sure where to start here, the good news is you have the best panels in the world.
If Health and safety were to see the pic of the chap standing on your roof, no scaffold, no harness and no brain in my opinion, I think there is a fair chance they would shut the company down...
Wouldn't get your system put right though, but a good ace to have up your sleve...
I think you have the right person involved here to help you so I will leave it up to him, too many opinions might not help either you or him to sort this mess out.

Added, there you go he beat me to it...

 

[MCS Renewables]

The DC isolator has four terminals and yours has two PV strings through it so they must have removed the jumpers .

see this ....http://www.scame.com/doc/ZP00860-GB-1.pdf

With these jumpers removed there is a high fire risk due to arcing during switching ......DO NOT TOUCH !!!


Personally have never used less than 4 mm for ANY AC wiring as part of a PV installation and 95% of our installations have 6mm or larger to minimise AC volt drop.
You will need to check with Solar River what the minimum cable size recommendation is.

If it was my home I would switch the whole system off at the AC sub mains board and await / demand a visit from NAPIT and the RECC .

 

[heliosfa]

Thanks for the quick reply, what do you mean by non fixings into the timber? the screws penetrating or the bracket spacing?

How do the cable sizes look? I was thinking of doing the calculations, but if someone already knows if these sizes are OK?

The deposit of £1.6K was paid for on my father's Credit Card (obv this doesn't invoke the Consumer Credit Act protection), but I could make a token payment on my card if they really push...

Re. them coming back, it was only to address the VERY dodgy AC wiring, but I did ask the "maintenance engineer" to check the rest of it, he had a brief look but didnt open any of the isolators, solardb, etc. etc. They have not been made aware of the other issues yet, I take it this does not affect how you recommend dealing with this issue? If not, I will raise the compaints today.

Just to summarise the documentation I have received:

• Datasheet for the Sunpower E20/333 and E20/327 Solar Panels (e-mailed with quotation)
• IWA Deposit Protectioncertificate (received by post the day after they did the "install")
• A single-page letter titled "dear solar investor" telling me that all completeion documentation, excuding completion receipt, EPC certificate, MCS certificate and Workmanship guarantee, are enclosed (handed to me by the installers)
• A part-completed FiT application for Good Energy (given with the "completion pack")
• A key-contacts form, a guide to maximising my system, a "customer cancellation form", a recommend-a-friend scheme thing and an invoice (e-mailed the day after the "installation".

According to the invoice, they charged £2.94K ex VAT for the pannels, £588 for the inverter and £882 for the mounting kit. In the "additional items", they have listed Scaffold, K2 Mounting System and Associated wiring & certification.


PS, what am I likely to be looking at to get this fixed - a complete strip-off and re-install? or is it repairable? What would the likely cost be (just out of curiousity)?

 

[MCS Renewables]

If you paid the initial payment by credit card then you have full protection. You can get your monies back under their insurances.

Switch the system off at new sub mains board for your own peace of mind and make urgent complaints to NAPIT and RECC as detailed above.

Don't pay the installation company any more and don't let them back on site, insist that NAPIT and RECC get an engineer out.

If the company get stroppy with you, your local trading standards office and the HSE website link above are available. You could also direct the company to this thread and they may offer you your monies back plus compensation, who knows.

The rest is up to you, it's so bad it probably needs to come off and start again but you are in a good position as the amount you have paid is covered by the panels you now have and you have credit card insurance.

As previously stated a replacement project with a decent German inverter will be under £7000 including VAT and a non invisible scaffold.

 

[heliosfa]

Oh my giddy Aunt, what a shambles, not too sure where to start here, the good news is you have the best panels in the world.

Thanks Earthstone, I will keep it all in mind.

If it was my home I would switch the whole system off at the AC sub mains board and await / demand a visit from NAPIT and the RECC .

Thanks,

I'm going to get one of my house mates to isolate it today.

What did you mean by non fixings into the timber? the screws penetrating or the bracket spacing?




So the problems that we have identified:

• Very Dangerous AC wiring (partly fixed)
• Very Dangerous DC wiring
• Unprotected exterior AC cabling
• DC cabling under pannels insufficiently secured
• Inapproriate DC cable entry to premises
• Potentially inappropriate inverter siting
• Invapropriately sized inverter
• Damage to/compromise of building weather seal
• Significant lack of documentation
• Uneven panel mounting

No EPC has been done as the property already has a valid one that gives it a "D" apparently.

have I missed anything?

I will start the complaints now, should I CC in the installers?

 

[MCS Renewables]

The fact that the screws may pull out from the timbers under windy conditions as the timbers are split.

You are going to have to deal with the installers tomorrow anyway when they contact you re the outstanding payment.

 

[marc8]

hi heliosfa

picture 5 looks intersting looks like 1.5mm 3core flex feeding meter & out to inverter lets hope it's not to far away then for volt drop.
sorry did not see pics till later does look like 2.5mm 3 core but still a s..t install.

 

[Gavin A]

I'm not sure I'd agree with the full shock horror comments, while it's not great, it's not obvious to me that this is as dangerous as MCS Renewables is indicating.

The DC isolator could well be rated to accept the relatively low voltage and ampage from the 2 strings of these panels with the links removed - we use some k&N isolators in this way with approval from K&N, and it will be low voltage and low ampage, so there would seem to be some conclusions being jumped to here without evidence to support them.

The AC cable probably is UV rated for external use, and I'm not convinced it is particularly undersized for a 3kWp system - it's certainly not dangerously so, though it could result in the inverter tripping out due to overvoltage if the local voltage is relatively high.

The choc block for the earth within the meter is pretty standard, it's allowed because it's within the extended cover of the meter, and there is no earth connection within those meters, so something along these lines has to be done.

The following definitely are issues that you should ask to be addressed, however they're probably not immediately dangerous in my view;

1 - DC cables into DC isolator to ensure not bare wire is visible

2 - DC cables tied up below the panels

3 - DC cable entry should be via the overlaps on the felt, and the holes covered. However IMO this is a relatively minor issue, as no house should be relying on the felt for water proofing, as if you do then the battens will end up rotting fairly quickly and the entire roof will need replacing rather than just the odd tile. It's also the case that in a lot of houses the loft isn't adequately ventilated after having additional insulation fitted, so the extra ventilation through the hole is likely to be beneficial rather than a problem - most damp and mould issues in lofts is from condensation due to inadequate ventilation following loft insulation top up IME.

4 - Roof bolts in rafters, obviously this isn't good, but how much of an issue it is depends on which brackets are affected, if it's just one screw per bracket affected (assuming at least 2 screws per bracket) and what the pull out value is for each screw. The pull out values for some screws used can be such that one properly fixed screw would be sufficient for brackets in the middle of the array, the second effectively supplies redundancy in case one screw doesn't take. That said, I'm amazed to see this on 50 x 75mm rafters, which should be easy to get the screws in properly for. I'd still insist that they sort this out if they're having to take the panels off to sort out the cables, I'm just making the point that the odd screw here and there not being fully in may well not particularly compromise the overall wind loading capability of the entire array depending on the factors detailed above.

4 - AC cable needs to be properly fixed to the wall via rawlplugs and screws if necessary.

In terms of the AC cable showing in the 'solar DB' I've seen a lot worse in factory fitted consumer unit links to the dual RCDs, I'd put that down as nit picking personally.

I would definitely take them to task on their lack of scaffolding, and ensure they had it if they do any further work on the roof. I'd think you'd end up pretty traumatised if the roofer had come off the roof apart from the HSE implications.

So some issues to be addressed, but I'd expect that NAPIT, RECC etc would expect you to give the installation company the chance to address them themselves before they'd consider taking any action.

 

[heliosfa]

So some issues to be addressed, but I'd expect that NAPIT, RECC etc would expect you to give the installation company the chance to address them themselves before they'd consider taking any action.

Thanks Gavin, They have been back once to sort out the bad AC side and they were asked to check the rest of the electrics at the time - so two of their installers think that this is OK.

Should the AC cable be left unprotected as it is? should it not be in conduit or have an RCD?



RE. AC cable size, according to the manual/installation guide for the inverter, 4mm^2 cable and a 25A breaker should be used. They have used 2.5mm^2 and a 20A breaker.

EDIT: If I amreading the "MCB with rated fault current of..." bit on page 16 properly, is the manual saying it needs an RCD?

EDIT2: should both strings be the same length to have the same voltage? the installers said that they were running the top 4 as one string and the lower 6 as a second. I take it that the easiest way to check would be a volt meter?

 

[Gavin A]

AC is protected, it's double insulated cable, so as long as it's UV resistant it can be classed as being ok. Personally we'd have used SWA, but it's not actually necessary as such as it's surface mounted, we just prefer the belt and braces approach. Plastic conduit is only needed if the cable itself isn't UV protected.

20A MCB offers greater protection than 25A, so is fine.

The Dual MPPT inverter means that the voltage of each string can be entirely different.

 

[heliosfa]

The Dual MPPT inverter means that the voltage of each string can be entirely different.

The manual implies that this is a single MPPT?

 

[MCS Renewables]

The inverter Installation manual says minimum AC cable size for this inverter is 4mm.

So AC cable undersized , DC Isolator dubious at best as marked AC in photographs, DC wiring poor, cable through roof shoddy at best although Gavin A suggests some roof cooling benefit !, mounting rail fixing bracket screws not in meat of joists so shoddy, Cable terminations shoddy, no generation meter labelling, no electrical certification left on site despite adding new mains board and circuit.
Plus massive HSE issues and some major shortcomings in the MCS paperwork system.

This is after the installation company have been out to sort out the issues !

Sorry but they had their chance to do the project right first time and then the re visit chance to put it right. They believe they are finished and want payment.

Companies like this need reporting and sorting out by RECC, NAPIT, Trading Standards and the HSE.

 

[whinmoor]

I'd also suggest getting them to change the inverter, if possible. A Power One Aurora PVI-3.0 OUTD would be a more sensible choice for this in my view.

 

[Gavin A]

The manual implies that this is a single MPPT?

my mistake, I thought that was the dual MPPT model. In which case their should be the same number of panels on each string, and cables lengths should be as similar as possible.

 

[whinmoor]

It looks like there's a chimney that may cause at least some shading. A twin-tracker would be certainly be preferable.

 

[Gavin A]

The inverter Installation manual says minimum AC cable size for this inverter is 4mm.

but it's going to be peaking at around 3kW not 3.68kW due to the array size. The cable loss diagram on the 3300TL version (which is equivalent to the actual output here) puts 2.5mm2 at being below 1% cable losses until around 17m.

Either way, that;s not a safety issue.

So AC cable undersized , DC Isolator dubious at best as marked AC in photographs, DC wiring poor, cable through roof shoddy at best although Gavin A suggests some roof cooling benefit !, mounting rail fixing bracket screws not in meat of joists so shoddy, Cable terminations shoddy, no generation meter labelling, no electrical certification left on site despite adding new mains board and circuit.
Plus massive HSE issues and some major shortcomings in the MCS paperwork system.

This is after the installation company have been out to sort out the issues !

Sorry but they had their chance to do the project right first time and then the re visit chance to put it right. They believe they are finished and want payment.

Companies like this need reporting and sorting out by RECC, NAPIT, Trading Standards and the HSE.

It's pretty rough, but I don't see any immediate safety issues that would result in it needing to be locked off as you suggested - that's just causing unnecessary alarm for the customer IMO.

And there's really no point in involving anyone else until the companies been given a proper chance to correct all the issues, as they won't do anything until this has happened IME.

- - - Updated - - -

It looks like there's a chimney that may cause at least some shading. A twin-tracker would be certainly be preferable.

agreed - partly why I'd assumed that was what the 3680TL was. I'd obviously given them too much credit.

 

[Gavin A]

EDIT2: should both strings be the same length to have the same voltage? the installers said that they were running the top 4 as one string and the lower 6 as a second. I take it that the easiest way to check would be a volt meter?

if this is what they've done then they have properly messed it up if it is a single tracker.

yes a multimeter will tell you what's going on, but be careful as there can be quite a flash from the DC, only do it if competent to do so, and only when the isolator is off please.

 

[MCS Renewables]

GAVIN A ....are you saying that you would ignore the manufacturers instructions and install 2.5mm cable because you did some calculations !!

 

[heliosfa]

I've done some more digging and reading of spec sheets and MCS standards - if I have anything wrong, please shout as my speciality is Electronic Engineering, not electrical...

The DC isolator could well be rated to accept the relatively low voltage and ampage from the 2 strings of these panels with the links removed - we use some k&N isolators in this way with approval from K&N, and it will be low voltage and low ampage, so there would seem to be some conclusions being jumped to here without evidence to support them.

From the spec sheet for the "DC isolator" (here, page 11), the maximum voltage for purely resistive loads is 300V. For mixed loads, it is 250V or 600V for two poles in series.

The panels have a rated load voltge of 54.7V and an OC voltage of 64.9V, giving a total of 273.5V, 324.5V open circuit, if the pannels are connected as two strings of five or 328.2V, 389.4V open circuit, if the pannels are connected up as they said (6+4). From this, two poles in series are required?

The AC cable probably is UV rated for external use, and I'm not convinced it is particularly undersized for a 3kWp system - it's certainly not dangerously so, though it could result in the inverter tripping out due to overvoltage if the local voltage is relatively high.

From the MCS PV installation guide (here, page 44) the recommended voltage drop is 1%. Using an online calculator, a 15m run of 2.5mm^2 seems to give a voltge drop of about 2% at the peak AC output current of the inverter.

The choc block for the earth within the meter is pretty standard, it's allowed because it's within the extended cover of the meter, and there is no earth connection within those meters, so something along these lines has to be done.

Agreed, i was more commenting on its presence than suggesting it was a problem.

It's also the case that in a lot of houses the loft isn't adequately ventilated after having additional insulation fitted, so the extra ventilation through the hole is likely to be beneficial rather than a problem - most damp and mould issues in lofts is from condensation due to inadequate ventilation following loft insulation top up IME.

This loft has plenty of ventiation as appropriate gaps were left when top-up insulation was done.

 

[heliosfa]

It looks like there's a chimney that may cause at least some shading. A twin-tracker would be certainly be preferable.

Yes there is a chimney. The property is oriented pretty much South-West. The original suggested panel layout (with a mix of portrait/landscape pannels) looked to have more spacing between the chimney and the panels but would have been a bit ugly. The layout was changed to the all portait on the morning by the installers.