G83

[Ted]

Connecting any small scale electrical generator (SSEG), such as PV, wind, hydro or CHP, in parallel to the UK grid is governed by several interlocking pieces of legislation.

Engineering Recommendation G83/1-1 (referred to as G83 below) is the current set of rules that apply to the connection of SSEGs to the public electricity network.  It has been drawn up, and continues to be developed, by a working group of the Distribution Code Review Panel (DCRP) formed under the control of the Energy Networks Association (ENA), a body made up mostly of members of the Distribution Network Operators (DNOs).

G83 is an annex to the UK Distribution Code which, in turn, is developed under the auspices of the Electricity Safety, Quality and Continuity Regulations (ESQCRs) as enacted by parliament. Any changes made to G83 are required to be approved and promulgated by OFGEM, who are responsible for overseeing the whole regulatory process.

The ESQCRs state that all systems, with one exemption, can be connected to the grid only with the prior approval of the DNO. The exemption applies in the case of an SSEG up to 16A per phase and where that system complies with the requirements of both G83 and BS7671. In this case you can connect the system and then tell the DNO when it is complete.

DNOs are allowed to apply discretion regarding the 16A limit where, based upon their detailed local knowledge, they are happy that the network can cope with a higher figure and that no detrimental effects will result for neighbouring properties.

There are some circumstances where an SSEG connection under G83 may be denied by a DNO, such as multiple SSEGs connected on a single transformer. Prior discussion with the DNO is the only sure way to find out if this applies in a particular case.

If you are planning to install an SSEG larger than 16A per phase then you must contact your DNO before you install the system. They may require a network survey to be conducted (at your expense) before agreeing that you can go ahead.

The ESQCRs empower the DNO to disconnect any property from the grid if they are not happy that the installation complies with the regulations.

G83 covers both the type-testing of particular products, such as inverters, to ensure that these comply with the appropriate technical requirements and also to the complete installation of a SSEG. Type tests are usually arranged by product manufacturers and have to be carried out by suitably accredited test labs and these labs may be in-house (for the larger manufacturers) or separate commercial operations.

When you purchase an inverter you should make sure that you get a copy of the G83 test certificate from the supplier.  Some manufacturers have copies which can be downloaded from their websites.

Details of the type of tests covered by G83 can be gleaned from the Type Verification Test Sheet - see ref below.

When an SSEG is installed the electrician responsible must complete and sign a commissioning certificate to confirm that the complete system complies with G83. The system owner needs to keep a copy of this and a second copy must be sent to the DNO. The completed paperwork must be submitted to the DNO within 30 days of the system being commissioned.

Other countries have similar, but not identical, regulations to G83. Germany, for example, has DIN VDE 0126 and Australia has something called AS 4777.
Ireland have decided to make use of G83 rather than going to the trouble of developing their own separate regulations.

In recent years there has been an effort to bring about wider EU and global harmonisation in this area through CENELEC and IEC. The same UK engineers who have developed G83 have been in the working group to develop EN 50438. Not surprisingly, as the UK has taken the lead in this, it generally embodies all the same requirements as G83.

Refs:
DCRP Constitution - http://www.energynetworks.org/dcode/pdfs/GBDCRP%20Constitution%20and%20Standard%20Procedures%20October%202009.pdf
DNO Contact details - http://www.energynetworks.org/engineering/pdfs/DG/DistributorNetworkOperatorContactDetails_071114.pdf
Electrical Safety, Quality and Continuity Regulations 2002 - http://www.opsi.gov.uk/si/si2002/20022665.htm
ENA - www.energynetworks.org
Grid Code - http://www.nationalgrid.com/NR/rdonlyres/67374C36-1635-42E8-A2B8-B7B8B9AF2408/35187/Complete_I4GridCode.pdf
G83/1 Type Verification Test Sheet - http://2010.energynetworks.org/storage/engineering/ER_G3-1_Appendix_4.doc
International Harmonization of Islanding Prevention Requirements, Woyte et al, 2003,  http://www.kuleuven.be/ei/Public/publications/EIWP03-09.pdf
Technical Guide to the Connection of Generation to the Distribution Network - http://www.energynetworks.org/engineering/pdfs/DG/FES_00318_v040211.pdf
The Distribution Code of Great Britain - http://www.dcode.org.uk/
Western Power - Connection Considerations for Distributed Generation - http://www.westernpower.co.uk/getdoc/8269db62-16ed-4fe2-ae7f-82ae794aeece/Connection-Considerations-for-Distributed-Generati.aspx
Western Power - Connection Considerations for Small Scale Embedded Generators - http://www.westernpower.co.uk/getdoc/3d0c88f4-7010-44c6-aa7b-7b78c44af0ce/Connection_considerations_for_small_scale_embedded.aspx
Western Power - SSEG Installation Commissioning Confirmation - http://www.westernpower.co.uk/getdoc/26ee74bb-96be-48ca-b5a1-4bfe88eb4f51/Installation_Commissioning_Confirmation_Form.aspx

Copies of G83 are available for purchase from http://www.ena-eng.org/ENA-Docs/eadocs.asp?WCI=DocumentDetail&DocumentID=8016

[edit - made a sticky]

[guydewdney]

I was going to give you a well deserved applaud for that, very concise, informative summary of the complexities of G83


but then you said "The ESQCRs empower the DNO" and that is just marketing speak twaddle - so you get a (wyleu style) smite instead LOL

[Ted]

Umm, it's not marketing twaddle - it is the use of the word in its correct sense. The power to do that is delegated to the DNOs.

[daftlad]

I am very glad we have THE TED, he explains lots of complicated stuff in ways us daft people can understand.
cheers Ted.
ta ta

[Tigger]

Ted,

I agree with you, it's the correct use of the word.  As a result of reading this, I felt empowered to applaud you 
.

[northern installer]

Ted,your endless research is rewarded with an applaud

[jotec]

Many thanks, It is getting clearer as time goes by.
D cik

[StBarnabas]

The ESQCRs state that all systems, with one exemption, can be connected to the grid only with the prior approval of the DNO. The exemption applies in the case of an SSEG up to 16A per phase and where that system complies with the requirements of both G83 and BS7671. In this case you can connect the system and then tell the DNO when it is complete.

Ted
one minor correction to this
http://2010.energynetworks.org/distributed-generation
On 4th August 2008, the Health & Safety Executive issued a Certificate of Exemption that effectively relaxes the timescales for notifying a DNO when comissioning Small Scale Embedded Generation (SSEG). The DNO must still be notified but in the case of SSEG this no longer needs to be before, or at the time of, comissioning. Notification must now be made within 28 days of comissioning.

Sean

[Ivan]

Of course the consumers' rights outlined in St.B's documents are at odds with the DNO's right to refuse permission for G83-compliant systems below 3.6kW if they want to. I don't imagine it's ever happened, but I'd be peeved if I'd spent several thousand pounds to then find the DNO enforcing their rights.

Incidentally, does anyone know what level of PV or wind you're allowed to install in Europe under their equivalent of G83, before needing to seek DNO's permission?

[Mistertea]

Ted's answer on 10.1.10 was very informative to me as a house builder with no electrical background One bit I need to clarify though. Ted says "There are some circumstances where an SSEG connection under G83 may be denied by a DNO, such as multiple SSEGs connected on a single transformer. Prior discussion with the DNO is the only sure way to find out if this applies in a particular case."
Does this refer to conection to the DNO transformer and therefore mean that if we are installing 1kwp pv systems on a street of 20 houses we should be talking to the dno first or is it the case that because all the properties are less than 3.6kw the house buyer will have no problem in getting a connection?

[guydewdney]

Talk to the DNO first - definately. The spec basically says that you can connect, with their permission, and they won't check the install (as its too small to worry about)

But you can't guarantee a connection - imagine you wanted to install 20 houses all with 3.6kva gennies - the local transformer wouldn't handle it - and the 'last' few houses would get refused.

Go have a look at the transformer - if its huge and close, then you might be OK...

[Ted]

Yes, as Guy says, you need to talk to the DNO first in these circumstances. They will be concerned about harmonic distortion as well as the total loading.

If this is a new build then there shouldn't be too much of a problem as usually the road will be fed from a 3 phase supply, with each house in a group of 3, on a separate phase. But in a rural area, with feeds from an overhead 11kV line, it could be quite different and until you talk to the DNO then you are not going to know.

[marshman]

"The DNO must still be notified but in the case of SSEG this no longer needs to be before, or at the time of, comissioning. Notification must now be made within 28 days of comissioning."

Can anyone tell me who notifies the DNO. Is the installer, the owner, the supply company paying the FiTs, OFGEM when you register with them???

I have filled in the FiTs agreement, got my MCS certificate etc. even supplied my first quarters meter readings so can I assume my DNO knows about me?

I am a little bit wary at the moment as I have put in a complaint to EDF, my DNO?, about high mains voltage which they are investigating (swells up to 257V frequently - as seen on their monitoring equipment.) I sit right at the end of the line in a rural area and am the only feed off of a small 11kV transformer.

Thanks for any info

Roger

[Ted]

I would expect the installer to do it.

Most DNOs have a copy of the required paperwork on their website so that you can see what info is required but, as the owner, you may not have all of that info to hand. The installer definitely should.

[JohnS]

I am a little bit wary at the moment as I have put in a complaint to EDF, my DNO?, about high mains voltage which they are investigating (swells up to 257V frequently - as seen on their monitoring equipment.) I sit right at the end of the line in a rural area and am the only feed off of a small 11kV transformer.

Thanks for any info

Roger

The DNO should be able to change the tapping on the transformer to give a lower voltage.  Often the voltage was set at the top end of the range if a lot of electrical power was going to be used.  E.g milking machines at a farm.