Solar Panels - cables loose on roof?

[whinmoor]

Did you check your installer was listed in MCS and REAL?

The Microgeneration Certification Scheme
Members - Scheme - REAL Assurance Scheme

Also, he should be with an accreditation body such as NICEIC, NAPIT, ELECSA, BRE, etc. His paperwork/website should say which he uses and he should be listed on their register of members.

These are your ports of call if you need to make a formal complaint but give him a chance to rectify the problems first.

 

[moggy1968]

Moggy's saying that 1200mm bracket spacings are fine on a bungalow in Dorset. I don't want to go out on a limb but the same may not be adequate for a house on a hill in rural Northumberland.

Sounds like a right mess to me, I'm afraid.

As I said, not suitable in your location
Their comments on long DC runs I suggest gives away a lack of knowledge. You would always keep the runs as short as possible, but not at the cost of compromising the rest of the installation. Technically speaking there is no problem with long DC runs, indeed because the voltage drop is less sometimes a long DC run is preferable to a long AC run.
I wouldn't want to run them inside the house, except in the loft, as there is no fusing on them, but an external run in conduit or SWA to the plant room would be fine, but depends on how practical that is. The IGTL can actually be mounted outside if things get really tight!

Good luck if you take it to the professional bodies, in my experience they don't give a sxxx!!

 

[Gavin A]

FYI - wind calcs need to be done, but on 4kwp array i would have expected more like 44'ish brackets.

depends on the mounting system and rafter spacing as well though.

If the rafters are at 600mm spacings we'd be installing on every other rafter alternating rafters on each row of brackets. The standard rail we use would allow 1200mm spacings, and the stronger version allows between 1400 spacings between the brackets even in the most extreme wind and snow loading conditions. Some of the more basic rails though wouldn't, so it depends what they've used.

It's hard to tell, but it does look like they've mounted all the brackets in line on the same rafter. If this is the case then IMO is more of a problem than anything else as it would mean all the wind and snow loading would be placed on those rafters, instead of being spread evenly across all rafters. Unless those particular rafters happen to be stronger than the others for some reason, or they've done calculations that demonstrate that those rafters can cope with the additional loading.

 

[moggy1968]

wind lift calculations are for what the roof will take, not the rails.
Alternating the rafters is a good idea, it saves weakening the same rafter in several places.
It can become a balancing act between having adequate brackets without causing too much damage to the rafters. HOWEVER, if a structural survey was done the engineer would have confirmed if the rafters were suitable as is for the number of brackets needed or whether reinforcement was needed
I would suggest 1.2m is too much in your area. If your rafters are at 600mm then everyone would probably need a bracket on every one.
As above, even down here we would expect 40+brackets on a 4kW system.

 

[dansk]

Sure, i tend to do outside bracket, then next rafter then every other.

Its hard to tell what's right or wrong when we don't know all the facts.

 

[The Solar King]

I mount every 800mm here in Scotland. Northumberland is not far away. This often means using noggins to support brackets. This is using Schletter. We are in a higher wind zone and often at altitudes up to 800ft, even in town.

Worcester has posted useful and interesting stuff on wind loading.

There will also be new advice in the 3rd Edition guide when published.

 

[loskie]

If you cannot resolve the issues with your installer you can pay a fee of around £120 to MCS or the accreditation body who will mediate with you and the supplier with the possibility of an unbiased survey. If found in your favour the fee will be returned.I had a lengthy exchange of e mails with my installer re some similar points. Eventually we had a meeting with the company MD and subcontractor at my house. The subbie didn't have a leg to stand on but still decided he knew better that HILTI technical on the use of their brackets. MD quietened him down a bit.Most matters were resolved and those that weren't were not really worth the hassle pursuing. But why they didnt just do the job correctly in the first place was beyond me. This was a simple installation by a reputable renewables company.the threat of incuding NICEICE(?) seemed to help. Maybe they didn't want other jobs to be revisited.Use the accreditation body for help. I found REAL and MCS to be largely useless as far as consumer protection goes.

 

[loskie]

A further q to my post above. My installation 18x200w Panels with Aurora 3.6 OUT inverter located in Loft(this was the best location for it). Should there be a visible earthing wire? The inverter was relocated after me complaining about lack of clearance from eaves (was as low a 30mm) I am sure there was an earthing wire prior to being moved afterwards there is none. I mentioned this to the sparky and he said there was not one. I am not sure if I remember correctly or not.

 

[powervan]

earth wire to inverta would be within the inverta! the earth wire your prob picking up on is if the inverta u have is a TL (dont use them so dont no) which would be from array to the fuseboard or if PME then to a ROD in the ground! but inverta will be earthed so dont worry!!

 

[powervan]

Changing subject i saw one instal today where panels on roof were a good 6 inches above ridge that will whistle in the wind!!!!!!!!!!!!!!!!!!

 

[dansk]

I found REAL and MCS to be largely useless as far as consumer protection goes.

Isnt that what REAL is for? :banghead:

 

[loskie]

Exactly what i thougt but REAL referred me to MCS who in turn referred me to the accreditation body. Real even told me they had closed my case due to a satisfactory outcome. Their error, at that point no action had been taken. It was very poor.

 

[dansk]

Real is a joke TBH - At least dick turpin wore a mask.

 

[farmerdave]

*Update*

We had a technician up here this morning (well, he turned out just to be the roofer that did the work - presumably a sub-contractor of the company we're dealing with). His attitude was very much "well, that's how we always do it, we just use the number of brackets we've been supplied with" etc

Apparently they normally let the wires hang loose on the roof because he says they're a real pain to get at to tie up, and they're not going to wear out anyway in 25 years. I pointed out that it was against building regs, and he said they'll take the panels off and tie them up (*Thanks forum - wouldn't have been sure of my ground otherwise!*)

On the subject of the 70cm overhang before the 1st bracket on the rails, the banging noises in a moderate wind and the general suitability of the installation for this exposed, windy location: he's going to install an extra 4 brackets on the West end of the array, so they are properly supported at that end (the other end is fine) bringing the total to 32 brackets. (unfortunately this may mean disturbing the flashing around the roof velux). He doesn't sound at all keen to install more brackets (to be fair, the brackets they've used are fairly chunky) and I'm not sure how to argue this further. I have asked what sort of wind calcs were done but haven't got anywhere, and I'm sure no structural survey was carried out.

As for the inverter installation, apparently that's the electrician's domain. Although he listened to what we had to say about it, he was fairly noncommital (ie. he wouldn't for example agree that taking a hammer to a new stud wall was not a professional thing to do).

So we await developments. I am still concerned about the number of brackets fitted, and that the panels might still bang in the wind (I accept that in severe conditions, some noise is inevitable, but surely they shouldn't bang in moderate winds, such as we get here frequently?) and that in a worst case they might disappear completely damaging the roof (not an uncommon ocurrence with our farm shed roofs!)

Thanks again for all the help
Dave

 

[whinmoor]

Thanks for the update. More brackets will certainly help maintain stability. Better to spread the load across different trusses if that's possible - someone mentioned that earlier in this thread, I believe. It sounds like they will tie up the cables which was your initial issue so hopefully that will get sorted.

You could try recording the sound from the banging and play it back to them. Most modern mobile phones have this facility. I must say, this has never been an issue for us although the winds we experience will be less severe than your exposed location.

The roofer won't know too much about the inverter. That's not really his job and he's not likely to criticise his electrician buddy.