Poor Solar PV Installation ??? Expert Help Needed

[Bucks]

I have just sent the following reply to him, Any advice / suggestions much appreciated,

"If just the 12 panels on the main roof is our only / best option then so be it,
So the Steca 2010 & the Powerone PVI 3.6 that others have said may be suitable are not then?
Also would it not be suitable / recommended to connect two of the top panels that are shaded by the boiler flue to the same string as the four lower panels,

I'm sure you can understand I'm just trying to exhaust all options before agreeing to anything."

 

[SolarCity]

To be honest, I'm not 100% sure that the Power One inverter would be suitable. It is certainly worth investigating though. I would urge your installer to speak to Power One and ask them. There is a Power One configuration tool downloadable which could answer the question. Certainly the 4 panels would not produce a high enough voltage in the inverters standard set up but I was told at the Segen technical conference that the lower voltage threshold could be lowered - presumably low enough for the 4 panels alone.

 

[vfr750]

I think you could use a power one 3.6 outdI am getting one soon so I have been checking specs on the inverter.They have a tool on the site http://stringtool.power-one.com/which says you can go down to 4 panels.

 

[solarsavings]

Yep the power one 3.6 will be ok ( the start up voltage will need to be lowered) you can ask your installer to check here Power-One String Tool

 

[Bucks]

THANKS Guy's,
My Installer is going to ring Power One tomorrow.

 

[SolarCity]

Fair play to your installer. At least he is going to good lengths to sort the issue.

 

[Bucks]

I have just got a estimate of £370 from our boiler engineer to move the boiler flue to the front of the house, unfortunately the boiler flue does not meet the manufacturers regs or something like that, so he would have to replace the whole flue & conections with the proper Worcester Bosch ones.

So my question is is it worth moving the boiler flue at a cost of £370 + disruption to the other side our new roof, we are obviously going to be doing something about the Soil pipe (probably a vent tile, or just lowering the soil pipe to just above roof level) & the possibly the ariel (not sure what yet though)

 

[JD6400]

If you have no joy with the power one , we have quoted up against solar edge inverters in the past that i think are a sort of hybrid micro inverter that is ideal for shaded systems .
I think it is a main inverter but with individual controllers on the modules ?

 

[nbown]

just an idea, why not have 2 inverters?

 

[solarsavings]

I've just checked again and it is suitable just needs the four panel string start up voltage lowered.

 

[Bucks]

I've just checked again and it is suitable just needs the four panel string start up voltage lowered.
View attachment 8350

Sorry I had deleted the post that you have just answered, as I was looking at the PVI-3600 & not the PVI-3.6-OUTD

 

[Bucks]

After our installer has been in touch with Power-One, we have gone for the PVI-3.6-Outdoor inverter.

Their technical guy said that the 4 & 12 would work with the voltage reduced to 126, but the system would work more efficiently if we had a string of 5 and a string of 11 and reduce the voltage to 160.

So he is recommending that we wire one of the top panels into the same string as the 4 lower panels.

 

[SolarCity]

In that case, I would recommend that you seek out the panel which will receive most unavoidable shading on the upper roof and make that part of the lower roofs string.

Good work from your installer. Great to see him improving the system for you. I can't fault him for that.

 

[Bucks]

We are only as good as our last job , and putting aside why your one ended up with the issues that it did ?
It is their chance to redeem their selfs , i have to admit i tend to judge a company not on how they preform day to day but more so on how they preform when faced with a cock up / problem , how ever it was created !
So here's hoping it goes well ?

Well said and I agree completely! Let's hope the OP's installer will now give the OP the installation he wanted.

Fair play to your installer. At least he is going to good lengths to sort the issue.

Good work from your installer. Great to see him improving the system for you. I can't fault him for that.

I cant agree with all the above comments more, he is pulling out all the stops to get the system sorted out for us, I'm pretty confident we will get there in the end.

 

[Bucks]

In that case, I would recommend that you seek out the panel which will receive most unavoidable shading on the upper roof and make that part of the lower roofs string.

That is what I pretty much asked eariler Note: the soil pipe & ariel will be sorted somehow!

Also would it not be suitable / recommended to connect two of the top panels that are shaded by the boiler flue to the same string as the four lower panels,

 

[Bucks]

Someone has sent me a email stating "The PVI-3.6 is a transformerless inverter so make sure that pv frames are earthed."

Can someone please clarify this.

 

[MorganPVI]

To ensure DC seperation with the AC side the DTI guide http://www.electriciansforums.net/photovoltaic-solar-panels-green-energy-forum/23511-pv-guide.html advises that the frames of the panels are earth via a ground spike.

 

[Worcester]

In addition if he is using the Power-One 3,6 OUTD (or any other transformerless inverter) he MUST ensure that the routing of the AC cable doesn't need to be RCD protected.

If the AC cabling needs a 30mA RCD neither Type A or Type B will work, and no protection will be provided.

So the AC cabling MUST be installed so as not to need RCD protection.

I'll tell you all more of the facts later (need a day to write it all up) in essence if he is using a TL inverter, NO type A RCD will work under DC fault conditions (nothing to do with the Inverter - what power-one, SMA et al have said is true - as far as it goes) and even a Type B RCD will 'nuisance' trip at 30mA

If the AC cabling cannot be installed such that 30mA RCD protection is not required then it'll have to be a Transformered Inverter and we're back to square one.

 

[Bucks]

Thanks Guys,
I'm all a bit confused now as I don't really understand what you are saying about the RCD business, I know that the whole property is protected by RCD.

 

[SolarCity]

Presumably you are not on a TT system - normally when you have are supplied by an overhead cable. Judging by the age of your house and the urban location, this seems unlikely. In these instances, your earth is obtained from an earth rod. This doesn't give great Ze (external impedance) readings so the RCD is there to offer ADS (automatic disconnection of supply).

It sounds more likely that your consumer unit is protected by RCDs - especially likely if you have had a consumer unit upgrade in the last few years.

If this is the case then a good solution would be to have a seperate consumer unit installed which is not RCD protected. This should be pretty straightforward to achieve.

 

[Bucks]

It sounds more likely that your consumer unit is protected by RCDs - especially likely if you have had a consumer unit upgrade in the last few years.

100% correct I installed it a couple of years ago when we extended the house.

If this is the case then a good solution would be to have a seperate consumer unit installed which is not RCD protected. This should be pretty straightforward to achieve.

That is exactly what I was wondering, as before I put this Dual RDC CU in, we had two one with RCD protection & one without, not a lot of room in the cupboard where all our electrics are though.

So just to confirm this PV system needs to be wired into a Non RCD CU (at the moment it is wired into the RCD)?

Also the PV Frames need to be earthed? could they be earthed to the earth near the meter as that would be a lot easier in our situation? or do they have to be earthed via a ground spike somehow?

 

[SolarCity]

If you take a picture of your incoming and post it on here, I should be able to give more of an idea if you need a spike or not.

And to confirm, yes, install the PV system on a CU which is not RCD protected. If space is limited then this may be tricky.

 

[Bucks]

Picture as requested THANKS, we will be able to fit a small CU with a bit of juggling other things around.

 

[SolarCity]

Okay, looks like a PME system to me. Get the installers to fit an earth rod. It may even make the cable run easier.

 

[Worcester]

@BiggsSolar, we had one recently looking just like that on closer inspection it turned out to be a really old TN-S so it meant bonding back to the cnsumer earthing terminal so it may be worthwhile just double checking.

@Bucks, it should say PME or similar somewhere near it (hopefully) - I couldn;t quite see from the photo. In a TNS system - the 'Earth' is connected to the metal braiding / sheathing around the main incoming cable.

 

[powervan]

senior members interesting read!ive got the message now (no 30ma) rcd on TL invertas!so have i got a call back coming? we installed a TL 4000 via 4mm swa and put it into existing 4 way board with(wait for it) 30ma protection! all tested ok ! no call backs and its been in over 2months? its an easy change so would rather go back now as i always tell clients we call back when passing to give system a visual check over!!

 

[edexlab]

I know of a couple of jobs done by other installers which were 4000TLs on 30mA rcds and there were no issues until the summer months when the output started to increase ,so if you can I 'd advise you to do it sooner rather than later

Also the installation manual does state that 4mm conductors is not permissable ,this needs changing to at least 6mm depending on length of run may be a larger csa

 

[Bucks]

@BiggsSolar, we had one recently looking just like that on closer inspection it turned out to be a really old TN-S so it meant bonding back to the cnsumer earthing terminal so it may be worthwhile just double checking.

@Bucks, it should say PME or similar somewhere near it (hopefully) - I couldn;t quite see from the photo. In a TNS system - the 'Earth' is connected to the metal braiding / sheathing around the main incoming cable.

On the cover for the earth terminals it says MLNS, another photo attached, don't know if that gives any clues.

 

[grandfortune]

Its a TN-S, looks like you have your neighbours there aswell

 

[JohnBoyZ]

I know of a couple of jobs done by other installers which were 4000TLs on 30mA rcds and there were no issues until the summer months when the output started to increase ,so if you can I 'd advise you to do it sooner rather than later

Also the installation manual does state that 4mm conductors is not permissable ,this needs changing to at least 6mm depending on length of run may be a larger csa

Just out of interest, what were the issues? Were there problems with the RCD or the inverter?

 

[SolarCity]

Having seen that second picture, it does look more like a TN-S system now.

 

[tonypaulhill]

Hi All
I am new to Solar PV Installation and have only carried out a few installations. I am like most people getting increasingly annoyed with cowboys in the trade (Electrical or Renewables). I only hope that when accreditation review time comes around the cowboys will get their just deserts. I would advise anybody who is not completely satisfied with their installation to speak to the installer's accrediting body and request an inspection.

I am using Solar Edge equipment on my installations as this system, complete with power boxes, minimises problems with shading bringing down the whole string, as the panels all operate independently and string length can be up to 25 panels on single phase installations and 50 panels on 3 phase installations.

This system is 100% safe on installation as power boxes reduce dc voltage to 1v per panel until system is paired with the inverter.

Thanks for reading my waffle - Tony

 

[Bucks]

Having seen that second picture, it does look more like a TN-S system now.

Would we still need a ground spike then, or could the panels be earthed into the earth point shown as I think that would be easier for us.

 

[Bucks]

Seem to have stopped getting email notifications even though I'm subscribed to the tread!

 

[GaryM]

Seem to have stopped getting email notifications even though I'm subscribed to the tread!

I think it's a common problem as I get non for any of the threads I'm subscribed to. Used to though.

 

[SolarCity]

If it's TNS like it appears to be then the earth could be taken straight back to the earth terminal shown in your photo.