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DIY solar PV installation - is it a good idea?

Posted by Paul Hutchens on 4 December 2013 at 9:13 am

Q. I am thinking of building a solar PV system as a project and doing the install myself. I have been told that I would not be able to claim the FIT (feed-in tariff) unless the system was installed by an approved installer, but that as long as the inverter had G83/1 approval I would be able to buy and install myself.  I am a qualified electrical engineer and although not working in the field for several years, I am capable of building the kit – just not sure of the current regulatory requirements.

What I ideally want to do is start with a SMA inverter, which has already been acquired, and then add panels as and when I can buy or make - i.e. the system will start at low power and then grow, ideally to around 10kw eventually. The current invertor is a Sunnyboy 3000TL, which would later be replaced or doubled up etc. as the system grows.

I do not want to roof mount as there is plenty of ground available and although FIT would be very desirable, my main goal is free electricity (on a shoestring!). As a novice to the solar power industry, I would appreciate any advice on what permissions are needed and from who, if any, and the best way to set about starting the project.

A: The solar industry has been set up to provide protection to the general public and to consumers with quite a sophisticated code of practice and certification system. This is called the Microgeneration Certification Scheme (MCS) and is relatively expensive and onerous to achieve. There are also sections of the building regulations (Part P (electrical safety) and L (conservation of fuel and power) in particular, but also Part A (structure) and C (water tightness)) which must be met.

So if you decide to install yourself you will need to ensure that you meet the building regs and be subject to a paid for inspection (normally £150 - £250) from your local authority building control department.

You will also need to gain permission from the district network operator (DNO) if the system is greater than 16 amps per phase (3.68kWp approximately) or if there are other PV systems in your proximity. If you want to grow to 10kWp then you may need a three phase electricity supply.  In any event you will need to inform them following the installation of the generation capacity.

Planning permission is generally not required unless the building is listed or in a conservation, AONB or SSSI area.

As a result, this does not make it easy – deliberately so – for those outside the industry to install these systems. A fully qualified installer will be MCS certified and meet the requirements of the building regs through their competent persons scheme.

This will not, of course, stop you from installing yourself providing that you are – or have access to people who are – competent in electrics (AC and DC) as well as the expertise to design, install and commission the solar PV system itself.

One thing that concerns me is your comment “start with a SMA inverter, which has already been acquired, and then add panels as and when I can buy or make - ie the system will start at low power and then grow”. The inverter has to match closely to the output of the panels (not just in kWp but also in amps and volts) to ensure that the system will work effectively and efficiently – and also be safe! The correct electrical design of these systems is critical and you should not simply add panels to an existing inverter.

Lastly, if you decide to install yourself you will save some money – but maybe not as much as you think as some 60-70% of the installed cost is the kit itself. You will also lose out on the feed-in tariffs and the export payments which are a big part of your financial return – possibly three times as much as your free electricity (assuming you use half the electricity you generate).

Perhaps you could come to an arrangement with a local installer that you supply and/or install some of the equipment allowing them to safely complete the installation, obtain all the correct permissions and enable you to claim the full financial benefit of your investment.

About the author: Paul Hutchens is founder and director of Eco2Solar, which installs solar systems around the UK.

If you have a question about anything in the above blog, please ask it in the comments section below.

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Comments

7 comments - read them below or add one

SHibbert

SHibbertComment left on: 6 March 2017 at 12:48 pm

Paul Fletcher is absolutely correct. I have just done and registered a 3kw system with the DNO, its not hard, no FIT, but with the right kit its worth it

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martinwinlow

martinwinlowComment left on: 19 December 2016 at 5:43 pm

One thing that immediately occurs to me after reading Paul's article is the issue of micro-inverters.  A DIY installation using these is as simple as it gets.  I have seen systems that are truly portable ie one 'standard' (~250W) panel hooked up to a micro-inverter which has a 3 pin plug on the end.  Set up the panel, plug it in and off you go!  It doesn't get any simpler than that.  I do wonder how these systems (that can be bought on eBay) sit with the regs, however.

But from a DIY perspective, a micro-inverter based system has to be the easiest - and probably safest way to go.  Anyone care to comment?

MW

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Roy Abel

Roy AbelComment left on: 9 August 2016 at 9:13 am

Hooray Paul Fletcher!! You still about? This should be made easy/ accessible - safe yes - but it is not beyond the reach of any competent sparky nor installation a challenge for anyone with construction experience. We should be rolling out these technologies not locking them up in capital intensive scemes and political whimsy.

btw- I have installed a 5kw 3-ph system DIY - non-FIT - only possible as a result of trade contacts. Information is so hard to come by -it's all geared to the trade not the domestic consumer. Do I have to register as a generator - even if for my own use? (I have a planning approved ground mounted system in the Highlands - and simply could not have afforded an MCS approved installation).

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Nickj

NickjComment left on: 18 December 2014 at 12:11 am

I am thinking about a DIY installation using hybrid pv thermal to heat a swimming pool with no connection to the grid. I have a non shaded embankment facing south to south west around the pool and a pool house for a heat store stainless steel using the thermal and an immersion heater to use the pv. This will be in southern France, I will hire in expert help if needed but will start out by myself. 

I see that dc can be used directly for immersion heaters does anyone have any experiance of this or will it be simpler to use an inverter  an an AC immersion system?

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Sims Solar Ltd

Sims Solar LtdComment left on: 28 January 2014 at 4:13 pm

Reading through this post I have some different perspectives on Paul H's response, so thought I'd throw my hat in the ring.

You mention ground mount, there are some permitted development rights (see Planning Portal) but beyond these you will probably need planning permission. The PD is not going to give you a big install.

Buying materials yourself will mean VAT at the Standard Rate, through an installer VAT will be at the reduced rate, something to think about.

With regards to growing the system; there are two important factors, one will be the start up voltage which on the 3000TL is 150v, so you are going to need at least 4 modules for the inverter to even wake up. The second will be the MPP range which depending on the model of TL3000 but starts at 175v and will mean a minmium of 7 modules to initiate powe point tracking. There are other factors too.

You will need to notify the Distribution Network Operator (DNO) post installation, they ask for the installers MCS membership number - you'll need to think about how you address this. The DNO will want to know that grid workers are not at risk from your installation.

To install a system with greater than 16A output will require DNO approval before yo can connect to the Grid.

My experience suggests you are unlikley to be able to install more than 6kW to a single phese supply without network reinforcement, but ask the DNO and they will let you know. If you have access to a 3phase supply then by nature of the 16A per phase, you could install 10kW under G83 regs.

Hope this helps?

 

 

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Civil Warrior

Civil WarriorComment left on: 20 December 2013 at 8:35 pm

I was also thinking of a DIY PV system. A 6k system would meet all my meagre needs and the excess could heat the hot water tank. The regulations are a real barrier for fixed installations, but what about a semi-portable system with panels on wheeled frames to be deployed at ground level (and kept in the garage when not in use), or a mobile installation like the Greenpeace Solar Truck  (parked in the driveway). Would these be bound by any regulations I wonder ? Anyway, good luck if you go ahead with it.

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Paul Fletcher

Paul FletcherComment left on: 20 December 2013 at 8:07 pm

I personally would encourage DIY. I am set up to design, advise, instruct, commission, service and maintain. You do not need FiTs to make a system pay back. One day FiTs will not exist in the same way, I imagine it will be just 'buy back' as it is in Guernsey. MCS is a good idea, we need standards and training. However restricting this to electricians is prohibitive. We need more installations, more installers, more training, and DIY is one more way to increase take up. BUT, a DIYer on their own could be a disaster without back up, experience and training. One day solar PV will be like kitchens and cars, where everyone knows about them, and what to do. And if someone makes a mistake, like anything in life that your mistake and your responsibility and your learning curve.

Paul Fletcher

Renew Guernsey Technical Services

Guernsey

Channel Islands

(Not FiTs, no Starts! No tears)

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