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.
If you have a question about anything in the above blog, please ask it in the comments section below.
7 comments - read them below or add one