UK G83/1 Standard for Solar Systems

I have been looking over my power graphs to see how my system has been performing and I noticed an obvious 'cap' at 3.6kW.  Some googling has informed me of the G83/1 and G59/2 standards brought in around a year ago which on checking, my system is set to the 'correct' G83/1 standard limiting at 3.6kW to keep under the allowed 16A export.

I can understand this 3.6kW limit for a 230V house, but I have only ever seen my house the lowest at 238V, more normally 242 - 245V and sometimes slightly higher when the solar system is going well (I've had power issue's in the past so keep an eye on the voltage levels with both an 'easy view' plug in power meter aswell as occasionally checking with a Fluke 75).  So as I thought I had bought a 3.84kW system, can anyone see any issue's if I change settings to the G59/2 as it still is going through the 16A mcb, and the base house load is minimum of 200W which removes some export Watts - the Power One 3.6 even limits it to 4kW anyway.  Even exporting the specified 3.84kW @ 240V is still only 16A (less at the more usual 245V), so can anyone see any issue's if I change the settings to G59/2?  I'd doubt it'd reach sustained >16A to cause the mcb to trip.

I know it's not massive amounts of power, but it's both principle aswell as trying to get the most out of a system I thought I'd paid for.



stuart's picture

Re: UK G83/1 Standard for Solar Systems

I expect in practise it would work fine, but when the system was installed the installers had to abide by a set of regulations and installation processes/procedures, these are dictated generally by the DNO (electric operator) which place the 16A limits I believe.

logic's picture

Re: UK G83/1 Standard for Solar Systems

Thanks for your thoughts on this Stuart

I'm thinking that the only difference at the inverter between G83 and G59 settings is the 3.6kW limitation.  I'll get home in about 10 days so will give it a try then.


Mr_Blank's picture

Re: UK G83/1 Standard for Solar Systems

You should not change the setting to G59, they have different disconnection times and under/over voltage frequencey settings which may cause problems tothe DNO network.


G59 is not just 'anything above 16Amps, but quite a different set of protection settings and you should put an application to the DNO before using G59 settings, and thay may not allow you to.


Once permission has been given and the setting have been changed, the DNO will require a set of G59 test to be made with a witness present (that they will send) at your expense. = you will proberbly also need a G59 relay to the grid too.

If you change the setting and not have witness test results and/or G59 relay,  and something goes wrong, you could be in for a very big bill!

Having a 3.84kwp of panels on a 3.6kw inverter is more than acceptable and will help optimize your yeild.

Hope this advise helps you make a sensible decision before playing around with your inverter!

logic's picture

Re: UK G83/1 Standard for Solar Systems


I guess what little that I could gain does not justify any risk/hassles then.  I'll leave it alone on G83.


Thank you

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