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Strict enforcement of G83/1 restricts installation of 4kWp solar PV

Posted by Chris Rudge on 30 August 2011 at 9:54 am

Many installers may have already encountered the newly enforced grid connected inverter G83/1 requirements recently. In simple terms, all the District Network Operators (DNO's) have finally got together and are now insisting that all installations should completely comply with G83/1 requirements (clicking the link will download the distributed generation connection guide). 

For the purposes of changes that affect us, this means you can no longer have a Grid connected renewable power system that can export more than
16Amps without special permission. In principle, this has always been the case, however when we first started installing PV some years back the DNOs (District Network Operators) were quite happy to bend the rules a little to accomodate a possible maximum of 17.4Amps. Now due to the heavier installation rates of PV, and possibly upsetting the balance of local electricity networks, the DNOs have laid out simple rules:

1) If the output of the system will never be more than 16Amps, install as normal with normal notification when the work is complete.

2) If the output of the system may exceed 16Amps, then a G83/1 Stage 2 application will need to be carried out. The DNO will carry out a network study to ensure the local network will take this extra power, possibly charging you up to £250 for costs, and will advise if you can indeed install this system. Do not install and connect the system first, or you may be issued with a disconnection notice.

This all sounds pretty harsh, but in practice its not so bad if you can adjust your thinking. One of the main problems until recently has been availability of a good range of 3.6kW inverters to match the UK G83/1 standard. These are now coming on board from all the manufacturers quite quickly. SMA (Sunny Boy) for example are simly de-rating their 4kW range and certifying for the UK. Easy!

On the other side of the coin, in the UK for the most part a 4kWp system will hardly ever generate 4kW. There will be occasions, on a south facing roof in midsummer, when the module temperature will be low enough to maintain efficiency, that you will see the meter clock over the 4kW mark. Otherwise it will lurk around 3.5kW, in bright sun, obviously less as
brightness reduces.

So, carry on installing those arrays of 3.98kWp, etc and connect a 3.6kW inverter. That way, you'll still be generating just about the same annually as you would by fitting a 4kW inverter.

Photo by Karen Roe

More information about solar PV and the question of 4kWp from YouGen

Are 4kWp PV installations a thing of the past as district network operators tighten the rules? (30 8 2011)

Don't limit your solar PV system to 4kWp (27 2 2012)

Solar PV information page

Feed-in tariff information page

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About the author: Chris Rudge is a qualified electrician who specialises in renewable energy.

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

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6 comments - read them below or add one


juanComment left on: 19 June 2014 at 10:53 am

Hi Tasha Kosviner, thank you very much for your reply. The reference you have left me is very interesting.  I wonder what the limit is for connecting a PV system at low voltage. In Spain is 100 kW, and UK do not know, because other references have told me that is 100 kW, 125 kW and 200 kW. This is my worst nightmare, I've been looking for several weeks, but I can not find any official reference. We would greatly appreciate you could help me.    Thank you very much in advance,    Greetings.

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Tasha Kosviner

Tasha KosvinerComment left on: 18 June 2014 at 11:34 am

Hi Juan

Have a read of our info section on Solar PV. You should find lots of useful stuff there. Let me know if you have any specfiic questions and I'll do my best to answer. Good luck with your project! 


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juanComment left on: 17 June 2014 at 11:36 am

Hi, I'm Juan Castro Martos, a student of the University of Jaén (Spain).    I am contacting you because I have to make a weekend of master project, in which I need to know about PV systems.  I would like to find information about the maximum power that can be connected at low voltage, and the rules that exist.    I would appreciate a lot to me facilitate some sort of above information, or where to find some references.    Thank you very much in advance.    Regards,    Juan Castro.

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Cathy Debenham

Cathy DebenhamComment left on: 9 May 2012 at 9:58 am

The modules are the panels on the roof. They generate electricity from light, and are more effective if they stay cool. So they will generate more on a bright sunny winter's day, than on a hot, sunny summer's day. I'm not the person to go into the science of why that happens. Hopefully a technical expert will add a comment that explains that.

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John Loder

John LoderComment left on: 8 May 2012 at 7:53 pm

Sorry but I'm new to this , so can I ask what is module temoperature and why does it matter?

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pigasusComment left on: 22 September 2011 at 9:03 am

Hi Chris,

I really like your suggested solution of installing an array of nearly 4kW but controlling it with a 3.6kW inverter.  I've also been reading recently about the SolarEdge Power Optimizer system and aside from it's ability to maximise output in general, I like the idea of being able to monitor each panel individually.  Do you think it would be sensible to use your solution while also installing the Power Optimizer system?  Or would the effect of reducing maximum output with a 3.6kW inverter make the Optimizer system redundant?

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