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BEC

Hello, I've been asked to quote for a large pv system. So far, I've only done domestic. I cannot find much solid info on the differences between g59 and g83, particularly on the design side. Also, will the standard domestic installers ticket qualify me to do this stuff or is it necessary to do further qualifications?

Can anybody help?
 
Commercial are a different ball game altogether.
You will probably need, Planning permission, structural survey, G59 approval, Asbestos testing and drilling, export metering, and you may need an EPC too.
You may also need cable upgrades, of course some of the above depend on the size of system and where it is to be sited.

I hope this helps.
 
Thanks Earthstore. Most of that sounds fairly straightforward. As for the cable upgrades, is there a regs that I can refer to or is it just 7671? Also, do you know if G59 approval required a separate qualification or can I do it under my G83 ticket?
 
Great news that there is still interest out there!!

Anyone can apply for a g59 if you know how to fill out the form as is my understanding. Planning with the DNO could take a couple of months depending on where you are. If the DNO want cable upgrades in the area to cope with surplus leccy going back onto the grid then this will incur cost and more planning time.

As well as the design and install differences you also have to think about any requirements the DNO may need you to implement such as a G59 rely and if they want to be there for a witness test then the kit you need for that pushes your cost up. They will confirm this when they respond to your application. We have done G59 installs in Sheffield where they didn't want a rely or witness test but the DNO did at an installation in Oxford. Both installations were the same size!

If it's your first one then I would advise using a subcontractor to learn from them and see whether it is viable for you to go it alone on future installs.

We use a subbie because we are yet to see whether it is worth the investment in training and kit, maybe if there is still a viable market in the coming months we will think about it. If you want me to put you in touch with the guy we have used pm me with your contact details.
 
To be honest it is pretty straight forward apart from the cash flow side if you are not that well established , even then this bit can still be tricky !
There are a few things that you need a heads up on and you really should consult with others that have gone through the proses and may have those ALL IMPORTANT contacts that will help the job move along swiftly .
If you like PM me your contact number and i maybe able to point you in the right direction or have a word with SolarRoofSol .
It is very possible to do it without asking those in the know but it is a bloody steep and potentially costly learning curve , you can trust me on that one !!!
 
I'm also working on a quote for my first LSEG (its been ticking along for 2 months), the installation side seems to be ok (I've got contractors for asbestos Drilling & specialist roofers etc). For me its tieing the Client down, to a contract. I can organise the G59 liase with planning and Structural engineers but I cant do that until I get a contract but the project might get blown out the water after Structural survey and DNO. How do you guys play projects like this, I'm thinking of a managment fee to create the project and do all the preliminaries before presenting with a final costings. This would be refundable if they then go ahead.


Does that sound fair, the fact the roof is corregated makes this project tricky compared to a nice modern roof !
 
I would talk to the DNO and ask them for their costs and get a feel on what they will require. This can then be added to the quote as a caveat, 'what if' scenario.

Also what measures are you putting in place for H&S on the asbestos roof apart from the drilling issue? It is weaker than tin and we always undernet to protect our engineers, this is additional cost that should be built into your quote.

The way I would work it is put your quote together as you would a SSEG and ask for a deposit to allow you to start the planning process as some elements will incur an up front cost. Add to your quote as a separate line 'what if' cost so there will be as few surprises to the customer.

I know it's a lot to think about especially on your first but there are loads of installations on farm buildings/barns so these issues can be overcome!
 
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Not sure how others have been doing it but we have never had to pay for a conformation as to weather upgrade work was or was not required from the DNO . Now if it was , that was a different matter !
Once this is done then look at the structural survey .
We always get the client to apply for the planning , but do all the paper work.
It will take you about 2 hours and maybe ÂŁ100 for a few drawings and that was a reasonably rare requirement , as you will find they have normally kept a copy of the original planning application for the barn that can easily be modified .

As for mounting on a Ag barn with corrugated , you can give me that scenario any day !
You normally have superb access , storage , heavy lifting equipment on hand and above all a more relaxed deadline while the scaffold is up , not to mention in my opinion the fastest and most convenient mounting system there is !
Nets are a absolute must !!!!!!!!!!
 
What size is the system to be BEC? You may be able to fit a bigger system than you think under G83/2 provided you use inverters with the correct verification.
 
I've not actually confirmed the size of the system but there is 2000m2 to be covered. I'm pretty sure that's out of G83/2!
 
Thanks for help everybody. I've received a feasibility study from the DNO so I will get started with that. It is a corrugated iron roof. Regarding the net-is that a safety net secured at all four corners of the building for falls?

Also, system design. Is that covered in the g59 or is it just BS7671 for cable sizes?
 
Check out the DTI guide, size the ac cabling as per 7671 for the equipment you are fitting, don't forget 4 pole isolation for the whole installation.
Size DC cabling as per bs7671 but allowing for worst case scenarios on loading eg shortcircuit current plus correction factor and open circuit voltage plus correction factor.

then make sure the volt drop is all within limits as specified as dti guide 1%AC and 3%DC

If you are fitting a below 50kw system then most dnos let you fit g59/2 type approved equipment and no g59 relays, if anything else you are looking at a relay box and probably witness testing from dno(some do some don't!)

The main factor is speaking to your DNO and making sure you know exactly what they want and get it in writing!!!!



another thing to organise is an export mpan which can take time, although we have had one within a day from ukpn!

Make sure you include some provisional costings for cable upgrades even if the DNO says it doesn't need to reinforce the network as they can change their minds daily, especially if the supplier has issues with meter changes.

hope that helps a bit!
 
I'd double check the roof type before ordering the nets in. Nets are only needed for fragile roofs and metal roofs aren't normally classed as being fragile roofs unless they're particularly thin sheeting / not properly supported or rusting badly.
 

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