G83 pre install application

G

Greenday

What size of array in kWp can you go up to before you have to do a pre install G83 application.

Central networks say 3.68kWp of panels is the maximum before the pre application on Appendix 2 has to made. They quote 45 days for a response although in practice at the moment it can be done in 2-3 weeks.

The 3.68kWp @ 230V would keep it below 16 Amp per phase. My argument with them is that it's what the inverter is rated at that is important and this is typically always smaller then the Array output if you use manufacturers design software.

What are other installers expereince with different DNO's
 
G83 refers to 16A per phase and 4kW per phase keeps you inside that as far as electricity boards are concerned (although in actual fact this is slightly more than 16A)

You do not need to notify the electricity board for anything that is G83 until the install is completed.

I would assume that the 4kW per phase figure refers to maximum solar array size and not inverter size.
 
I would be very careful if you install in the Central Networks area as in the past they have never queried installs up to 3.8kWp.

They have rejected a 3.8kWp install we have completed and require an appendix 2 G83 application. This application process should be done pre install.

We always do a pre install application if we are up at 4kWp as a well matched inverter would definetly be over 16A per phase
 
My experience is that Central Networks (rightly) have no problem with anything up to 16A output, and use the max inverter output current you specify on the G83 appendix form you submit after installation for their decision and power calc. (this is where the 3.68kW comes from - not to be confused with kWp rating of the modules). Nothing to stop you hanging 10kWp of modules on the roof (other than common sense) providing the inverter can't dump more than 16A onto the grid. It is entirely feasible that 4kWp of modules will work well on an inverter rated at no more than 16A output.
 
I have actually asked someone from MCS this very question and he reckons that 4kW was the limit, rather than the 16A. Maybe I need to change my perspective?
 
The limit is 16A according to G83 ie. a nominal 3.68kW system output. Not to be confused with kWp of the modules, where 4kWp is the limit before the feed in tariff drops. Wouldn't be the first time someone from MCS didn't know what they were on about.
 
The jobsworth I spoke to at Central Networks said they will not accept a post install G83 on modules greater than 3.68kWp irrespective of inverter output.

They pick up the array output off the as installed/proposed install diagram, so theres no hiding it.

I always assumed they took the Amps output from the G83 info for the inverter that you have to submit. Apparently this is not the case as the letter I have in front of me proves.

Can anyone on here help clear up this grey area as one day this is going to cost an installer in charges to strenghten the grid after they have completed an install. I guess if we all start pre install notifying of an installation that a back log will build up delaying installations
 
There is a lack of clarity on this issue and each DNO seems to have their own interpretation. I wrote to OFGEM a couple of weeks ago to try to get clarification on a number of these issues around G83 and the threshold values. I have not yet had a reply.

Here is the letter:

Dear sirs,

we write regarding the issue of OFGEM policy and implementation of DNO terms and conditions surrounding the aspect of the 16A per phase limit as it relates to the installation of renewable technologies under the terms of Engineering Recommendation G83.

We have heard reports of recent instances where DNOs are either refusing connection for <3.6kW domestic renewable systems under the terms of G83 or requiring payment in order to perform local network reinforcement in order to allow G83 compliant systems to be connected.

Also some DNOs have indicated that they require prior notification of an installer's intention to connect a new system under G83 prior to commissioning and that they retain the right to refuse any such connection or impose other terms. We fully understand that DNOs can make these requests where multiple G83 systems are involved, but this now appears to be the DNOs approach on individual systems
as well.

This does not align with our understanding of the way that Electricity Safety, Quality and Continuity Regulations 2002 require DNOs to behave with regard to individual G83 connections.

We also note that DNOs receive some level of compensation for Distributed Generation (which is inclusive of capacity for G83 systems) under the terms of CRC11 in DPCR5. If DNOs are now also charging G83 customers for network reinforcement measures then does this not lead to some level of double funding for DNOs that would be outside the terms of their operating licence from OFGEM?

We have heard reports that OFGEM have taken steps in the past to prevent DNOs from charging customers for costs of network reinforcement where G83 systems are concerned. Is this correct and, if so, can you confirm under what basis this was done and what procedures customers should follow to seek this redress?

Additionally, we would like to take this opportunity to seek clarification from OFGEM on the following closely related matters.

1. DNOs are allowed to use their discretion to accept a >16A per phase system under G83 terms, based on their knowledge of the local network capacity. Once a DNO gives their agreement on this basis is this decision irrevocable or are they allowed to change the terms at a later date (when other changes may have happened in the meantime, such as additional G83 systems being connected in a locality) and then request that the original system complies with G59 - including requiring the customer to pay any associated DNO costs? Also clarify this matter where such multiple systems (such as wind and PV) may be connected at a single location over a period of time where, taken individually, each system comes below the G83 threshold but, taken together, they may exceed it.

2. As regards multiple G83 connections, in a single locality at the same time, are the costs of any required network reinforcement, that may be required to accommodate these, to be passed on to customers or to be borne by the DNO?

3. Can we get clarity as to exactly what the 16A per phase limit for G83 actually relates to? Is it based on:
a) the Declared Net Capacity or the Total Installed Capacity of the system (as given on the MCS commissioning certificate) ?
b) the manufacturers quoted peak output of the PV panels (or other applicable prime mover 'nameplate' figure) ?
c) the maximum grid-tie inverter output?
d) if it is based on the inverter output then is it based on the manufacturer's maximum rating for the model of inverter or based on the (sometimes programmable) actual maximum inverter output figure
e) figures used at a - d above are usually given in Watts - so, in order to convert to Amps, is 230V or 240V to be assumed? I believe the definition in G83 specifically states "230V ac" but many DNOs seem unaware of this minor fact.
f) can you confirm the maximum Watts applicable to a 3-phase supply?

4. Can OFGEM please confirm that DNOs are not entitled to charge any costs connected with making an offer for connection, as was laid out in Section 98 of the Energy Act 2008, in respect of G83 connections where a grid connection for import already exists at a location, until such time that the Secretary of State may make such an order, and that such an order would explicitly include or, indeed, exclude G83 connections from such a charging scheme?

5. How might the G83 threshold apply in a situation where a >16A per phase system has been designed to prevent no more than 16A per phase from being exported; e.g. a controller and dump load used for on-site heating for any excess that might be generated?

Would it also perhaps be timely to pass answers to these questions to all DNOs with a reminder of how they should be handling individual and multiple G83 connection requests, concerning both process and costs, so that there is a common experience for both renewables installers and prospective system owners across the whole of the UK? Perhaps it would be appropriate for these matters to be discussed at a forthcoming meeting of the Distribution Code Review Panel?
 
Your letter address's all the concerns we have surrounding G83.

I had a conversation with an engineer from Central Networks four months ago about this issue and couldn't get clear guidance. Unfortunately I had the same conversation with the same stroppy engineer on Friday and he would go no further with an explanation on policy than "you cant install more than 3.68kWp of panels mate-end of"

I think all on here would appreciate hearing what response you get to your letter--could you keep us informed?

To protect ourselves we are going to pre notify before installing anything over 3.68kWp of modules until their policy is clear

Our engineer chap added as a parting shot that Central Networks were going to put an idiots guide on their web site so i'll keep my eyes open for that!--nice helpful chap :rolleyes:
 
TedM said:
There is a lack of clarity on this issue and each DNO seems to have their own interpretation. I wrote to OFGEM a couple of weeks ago to try to get clarification on a number of these issues around G83 and the threshold values. I have not yet had a reply.

Here is the letter:

Dear sirs,

we write regarding the issue of OFGEM policy and implementation of DNO terms and conditions surrounding the aspect of the 16A per phase limit as it relates to the installation of renewable technologies under the terms of Engineering Recommendation G83.

We have heard reports of recent instances where DNOs are either refusing connection for <3.6kW domestic renewable systems under the terms of G83 or requiring payment in order to perform local network reinforcement in order to allow G83 compliant systems to be connected.

Also some DNOs have indicated that they require prior notification of an installer's intention to connect a new system under G83 prior to commissioning and that they retain the right to refuse any such connection or impose other terms. We fully understand that DNOs can make these requests where multiple G83 systems are involved, but this now appears to be the DNOs approach on individual systems
as well.

This does not align with our understanding of the way that Electricity Safety, Quality and Continuity Regulations 2002 require DNOs to behave with regard to individual G83 connections.

We also note that DNOs receive some level of compensation for Distributed Generation (which is inclusive of capacity for G83 systems) under the terms of CRC11 in DPCR5. If DNOs are now also charging G83 customers for network reinforcement measures then does this not lead to some level of double funding for DNOs that would be outside the terms of their operating licence from OFGEM?

We have heard reports that OFGEM have taken steps in the past to prevent DNOs from charging customers for costs of network reinforcement where G83 systems are concerned. Is this correct and, if so, can you confirm under what basis this was done and what procedures customers should follow to seek this redress?

Additionally, we would like to take this opportunity to seek clarification from OFGEM on the following closely related matters.

1. DNOs are allowed to use their discretion to accept a >16A per phase system under G83 terms, based on their knowledge of the local network capacity. Once a DNO gives their agreement on this basis is this decision irrevocable or are they allowed to change the terms at a later date (when other changes may have happened in the meantime, such as additional G83 systems being connected in a locality) and then request that the original system complies with G59 - including requiring the customer to pay any associated DNO costs? Also clarify this matter where such multiple systems (such as wind and PV) may be connected at a single location over a period of time where, taken individually, each system comes below the G83 threshold but, taken together, they may exceed it.

2. As regards multiple G83 connections, in a single locality at the same time, are the costs of any required network reinforcement, that may be required to accommodate these, to be passed on to customers or to be borne by the DNO?

3. Can we get clarity as to exactly what the 16A per phase limit for G83 actually relates to? Is it based on:
a) the Declared Net Capacity or the Total Installed Capacity of the system (as given on the MCS commissioning certificate) ?
b) the manufacturers quoted peak output of the PV panels (or other applicable prime mover 'nameplate' figure) ?
c) the maximum grid-tie inverter output?
d) if it is based on the inverter output then is it based on the manufacturer's maximum rating for the model of inverter or based on the (sometimes programmable) actual maximum inverter output figure
e) figures used at a - d above are usually given in Watts - so, in order to convert to Amps, is 230V or 240V to be assumed? I believe the definition in G83 specifically states "230V ac" but many DNOs seem unaware of this minor fact.
f) can you confirm the maximum Watts applicable to a 3-phase supply?

4. Can OFGEM please confirm that DNOs are not entitled to charge any costs connected with making an offer for connection, as was laid out in Section 98 of the Energy Act 2008, in respect of G83 connections where a grid connection for import already exists at a location, until such time that the Secretary of State may make such an order, and that such an order would explicitly include or, indeed, exclude G83 connections from such a charging scheme?

5. How might the G83 threshold apply in a situation where a >16A per phase system has been designed to prevent no more than 16A per phase from being exported; e.g. a controller and dump load used for on-site heating for any excess that might be generated?

Would it also perhaps be timely to pass answers to these questions to all DNOs with a reminder of how they should be handling individual and multiple G83 connection requests, concerning both process and costs, so that there is a common experience for both renewables installers and prospective system owners across the whole of the UK? Perhaps it would be appropriate for these matters to be discussed at a forthcoming meeting of the Distribution Code Review Panel?
Click to expand...

Couldn't of put it better myself. Don't think you missed anything out there. Well done and a very useful post. Keep us up to date when or IF you get a reply. Thanks
 
Of course I'll be happy to post any response I get. I don't plan to let this drop and my MP will be rolled into the firing line if I don't get a sensible reply with the next month or so, and escalated from there any way I can find.
 
Quite right too. As usual, the rules aren't clear but you can bet they'll be enforced with great vigour and little common sense. What chance do we have?
 
Spoke to a guy from Scottish & Southern last week. Now the new version of G59 has been released they are being more stringent on the G83 limit. They are reviewing the situation and I was advised to keep within the 3.68kWp limit for the time being. More clarification maybe avaiable in a few weeks.
 
We have a meeting with ofgem on the 12/1/2011. We have had numerous returns from the dno for all over 3.6 kw. first time in 10 months we are now putting pre installation applications for all over 3.6 kw. A bit of a git as we have installed over 160 systems 70% of which are over 3.6kw
 
From my experience i've had touble connecting a 3.5kW system and have been told that the biggest PV system i can install on one house is only 1.9kW. This is way below the 16A G83 limit. Problem is due to overhead lines. On higher outputs the voltage would rise due to volt drop and the inverter would shutdown. Just as well we checked before we installed.
On another note we can apply for an extended G83 up to 42A rather than use G59. My advice is to get a friendly engineer from your DNO and check before you install anything.

simon
South West Free Energy Solar Powers, Solar Energy, Save on your Electricity Bill South Devon
 
sherbert said:
From my experience i've had touble connecting a 3.5kW system and have been told that the biggest PV system i can install on one house is only 1.9kW. This is way below the 16A G83 limit. Problem is due to overhead lines. On higher outputs the voltage would rise due to volt drop and the inverter would shutdown. Just as well we checked before we installed.
On another note we can apply for an extended G83 up to 42A rather than use G59. My advice is to get a friendly engineer from your DNO and check before you install anything.

simon
South West Free Energy Solar Powers, Solar Energy, Save on your Electricity Bill South Devon
Click to expand...

Out of interest what DNO is that?
 
Reply received from OFGEM concerning the email I sent (see earlier post):


Many thanks for your email. My colleagues in Consumer Affairs passed your query on to me a few days ago and I am now emailing you with our response.



As an initial point we would like to direct you to the DG information guide which has recently been published on the ENA website http://2010.energynetworks.org/link-to-engineering-documents/ (see first 4 documents under Engineering documents-free to download).
This document should clarify quite a few of the queries you have raised below. In addition, there is a feedback mechanism in place to comment on this guide and alert the ENA if there are any bits of information missing. We would also be happy to hear if any information has been found to be missing from the guide.


In addition, we wish to point out that the G83 standard is administered and interpreted by the ENA and therefore several of your technical questions regarding the meaning of this standard should be directed to the ENA in the first instance.



Therefore, I would advise you to review the DG information guide. If you could then let me know if any of your queries are still outstanding. In the meantime, we are reviewing the sections of your query that we feel we can respond to.


Kind Regards


Stacy Altman
Senior Policy Analyst
 
Greenday said:
What size of array in kWp can you go up to before you have to do a pre install G83 application.

Central networks say 3.68kWp of panels is the maximum before the pre application on Appendix 2 has to made. They quote 45 days for a response although in practice at the moment it can be done in 2-3 weeks.

The 3.68kWp @ 230V would keep it below 16 Amp per phase. My argument with them is that it's what the inverter is rated at that is important and this is typically always smaller then the Array output if you use manufacturers design software.

What are other installers expereince with different DNO's
Click to expand...

I'm still not clear whether it's the rating of the array or inverter that is taken into account. Central networks still insist that any array over 3.68kW requires a pre install g83 appendix 2. Our view is if the output from inverter which is g83 approved is less than 16A then no pre install notification is necessary. This was backed up last week by Electricity North West who queried why we had submitted a g83 appendix 2 for an inverter that operated at 15A (total array size was 3.8kWp)

Can someone point me to the document that clearly states that it is the output of the PV array that need to be considered for g83 and not the inverter
 
In Scottish & Southern territory size for the purposes of G83/G59 is the lesser of 1 of the 2 following:

1) peak output of the panels times the max efficiency of the inverter

2) continous rated output of inverter
 
This is one of the questions that I am now awaiting a reply from ENA about.

Clearly each DNO cannot setup their own rules.
 
TedM said:
This is one of the questions that I am now awaiting a reply from ENA about.

Clearly each DNO cannot setup their own rules.
Click to expand...

This is the problem. Although having 16A as a rule and allowing larger on consideration seems like a reasonable way to go.
 
If the output of the inverter cannot go above 16A, what business is it of the DNO if I have 3.68kWp or 36.8kWp of modules stuck on the end of it? So far all our systems have been under 3.68kWp anyway, so nothing has been flagged up by the DNO. However, tomorrow we fit a 3.9kWp system with an inverter limited to 15A output. It will be interesting to see if Central-Networks flag this up as an issue. I shall enjoy arguing the ---- with them until I am blue in the face.

Seems crystal clear to me that G83 allows up to 16A to be injected onto the grid. Surely if I fit an inverter with a max output of or below 16A there is no problem? Am I missing something blindingly obvious here that means, in these circumstances the size of the array has any baring on this whatsoever, regardless of what the inverter can actually deliver? OK, if I fit a bigger inverter, then potentially 16A can be exceeded, depending on the kWp rating of the array. However, 4kWp can be accomodated with an inverter limited to 16A no problem. Limiting the array to 3.68kWp only has a direct bearing on the amount of current injected onto the grid if the inverter is 100% efficient and grid voltage is 230v. ie, it ain't gonna happen.

Seems to me that the DNO's need to send their decision makers on a decent training course. Monkeys.

Cheerio

Dr. Ranty McRanterson
 
Interestingly, Central-Networks seem to have changed the way they assess system size only recently. On a couple of our installs from a few months back, they simply multiplied the stated inverter max output current x 230v and confirmed this as the size of system when writing to the customer. On our last couple of jobs they are indeed taking the array size as the system size.
 
Here is the reply I have received from OFGEM on the questions posed back in November.
It has taken exactly two months to get this response.
I'm still waiting for any acknowledgement from ENA.

------------------------------------------------------------------------------------

Ted

In response to the rest of your email from November, we have outlined below our response.

1) refusal of connection or requiring payment to perform local reinforcement work

DNOs have a duty under the Act to connect on request and under the obligations of their distribution licence, licence condition 12 they have a requirement to offer terms for connection and use of system. In terms of charging for the cost of reinforcement work, Ofgem believes that it is reasonable for a customer to pay for the cost incurred of making a connection and therefore reinforcement work should be borne by the customer. However, we are unclear how that has a bearing on G83 where I believe the threshold sizes of generation are very small.

2) requirement to inform prior to installation and retain the right to refuse or impose other terms

It is again worth noting that DNOs have a requirement to offer terms for connection and use of system. The standard licence conditions can be accessed on our electronic public register on the Ofgem website. If you look for standard licence conditions in the open blue window of the e-register under the search box which is titled "Electronic Public Register". Under G83, there is a requirement for notification to the DNOs of an installation.

3) alignment with the ESQCR 2002

This is a question for the ENA who should be able to comment on the relationship between G83 and these regulations

4) compensation for DG

The DG Incentive is designed to encourage DNOs to connect DG efficiently. The DNOs are allowed to pass through 80% of the costs of reinforcement, i.e. get reimbursement for through UoS charges. This does not include any costs paid for by the customer but the incentive effectively covers the remaining 20%. The DG incentive only applies to DG that pays use of system charges – which we interpret to mean DG with an export meter. Therefore, not all installations that apply under G83 would earn a DG incentive. Finally, the amount that a DNO can earn under this incentive is capped against the amount that has been spent on reinforcement. Therefore, if a lot of DG connects which does not require reinforcement, the amount of DG incentive they earn is capped.

5) reports that Ofgem has taken steps in the past to prevent charging

We cannot comment on second hand information. We would need evidence or citation indicating our action in this regard.

Thereafter you included some specific points of clarification in the rest of your email. In general we feel these questions are best directed to the ENA as they directly relate to interpretation of the G83 standard, however we have provided whatever guidance we could below:

1. This should be directed to the ENA. However, we believe that there is some explanatory wording in the next standard up, G59 which may clarify this query.

2. According to the charging methodology, which is approved by Ofgem, customers must pay the cost for any required network reinforcement.

3. All of your query on what the 16A phase limit for G83 relates to should be directed to the ENA (though it may also be in the DG guide)

4. This should be clarified in the DG guide. In addition, in general, upfront fees are not allowed to be charged for the provision of a quote, however, we are not sure how this relates to G83 connections and therefore refer to the DG guide as a first point of information

5. We also feel that this may be in the DG guide and otherwise may be directed to the ENA.

6. As you are already in contact with someone from the ENA, it may be worth forwarding your query in its entirety and this response to a contact in the ENA and suggesting review of the questions and possible raising of this with DNOs at a suitable forum.

Kind Regards

Stacy
 
I received a reply this afternoon from the Energy Network Association to the questions raised about various G83 issues. Their reply is reproduced below with the original questions added back in in bold to aid readability. (I've not corrected any of the minor typos in the reply.)

Date: Tue, 22 Feb 2011 18:02:52 +0000
From: David Spillett <[email protected]>

Please find my response to your questions below.

Firstly In relation to the reference of refusal to connect above 1.9kW, G83/1-1 2008 caters for Small Scale Embedded Generators upto 16A per phase (3.7kW single phase and 11kW 3 phase). I am not aware of any DNO refusing connections above 1.9kW unless possibly there may be safety related concerns or equipment is not type tested as required by G83/1-1. G59/2 (2010) caters for connections above 16A per phase.

Q1 - DNOs are allowed to use their discretion to accept a >16A per phase system under G83 terms, based on their knowledge of the local network capacity. Once a DNO gives their agreement on this basis is this decision irrevocable or are they allowed to change the terms at a later date (when other changes may have happened in the meantime, such as additional G83 systems being connected in a locality) and then request that the original system complies with G59 - including requiring the customer to pay any associated DNO costs? Also clarify this matter where such multiple systems (such as wind and PV) may be connected at a single location over a period of time where, taken individually, each system comes below the G83 threshold but, taken together, they may exceed it.

DNOs were... and still are.. but the protection settings should conform to G59/2. Contracts can always be renegotiated - and if a customer doesn't like this, they can go to Ofgem for a determination.

However this is the formal background and I would not expect a DNO to change any terms retrospectively for domestic scale customers.

Where G83 applications in the same locality are genuinely independent, they would be treated as such and no reinforcement costs charged to any of the applicants. However, if "multiple systems...connected at the same location" means all within the same premises, it should be expect that DNOs will aggregate the electrical output of those individual sources of energy, in deciding whether or not the 16A per phase limit had been reached.

If multiple systems, each less than 16A are connected at different connection points but in the same locality then stage 2 of G83 is applied.


Q2 As regards multiple G83 connections, in a single locality at the same time, are the costs of any required network reinforcement, that may be required to accommodate these, to be passed on to customers or to be borne by the DNO?

The cost of any works to facilitate the connection/s will be assessed in accordance with the DNOs “Statement of Methodology and Charges for Connection to the distribution system.


Q3 Can we get clarity as to exactly what the 16A per phase limit for G83 actually relates to? Is it based on:
a) the Declared Net Capacity or the Total Installed Capacity of the system (as given on the MCS commissioning certificate) ?
b) the manufacturers quoted peak output of the PV panels (or other applicable prime mover 'nameplate' figure) ?
c) the maximum grid-tie inverter output?
d) if it is based on the inverter output then is it based on the manufacturer's maximum rating for the model of inverter or based on the (sometimes programmable) actual maximum inverter output figure
e) figures used at a - d above are usually given in Watts - so, in order to convert to Amps, is 230V or 240V to be assumed? I believe the definition in G83 specifically states "230V ac" but many DNOs seem unaware of this minor fact.
f) can you confirm the maximum Watts applicable to a 3-phase supply?

(a) For Inverter systems it is the output of the inverter so it would be possible to install a 3.6kW inverter with 4kW peak of PV panels under G83
(b) No see answer above
(c) Yes see answer above
(d) maximum continues rating
(e) 230 volts is the nominal voltage for the whole of Europe
(f) 230x3x16= 11,040 for practicable purposes this is 11kW, split evenly over three phases. The following is not allowed
phase 1 4kW
phase 2 4kW
phase 3 3kW
as two phases exceed 16A per phase

Unbalance is allowable up to to the following limit
phase 1 3.7kW
phase 2 3.7kW
phase 3 any value under 3.7kW


Q4 Question directed to Ofgem


Q5 How might the G83 threshold apply in a situation where a >16A per phase system has been designed to prevent no more than 16A per phase from being exported; e.g. a controller and dump load used for on-site heating for any excess that might be generated?

The system would need to be type tested for G83 to be applied.


Best Regards

David Spillett
Energy Networks Assocation
Dean Bradley House
Horseferry Road
London
SW1P 2AF
 
Good work TedM thats answered a couple of outstanding questions I had ,that I've been asking central networks and sp manweb for 3 months and still no reply!
 
The next step will be to try to get all DNOs to recognise the stated standards so that we have a common approach for all of the UK. If any of you have any difficulties - especially with the G83 limit applying to inverter output - I suggest the first thing you try would be to quote this email.
 
What a load of -------s G83 is. It limits generation to 16A per phase and the allows manufacturers to build inverters that go up to 20A.
However, the kw output is derived from several factors, power factor being one and supply voltage being the other. It has been stated several times that 16A = 3.68kW, this is only correct within a pf range and essentially the supply voltage being at the nominal 230V, which we all know is not the case almost every where in the UK. The voltage tolerance in the UK from the nominal is +10% -6%, I believe at present. This puts the kW output from a 4kWp system between (-6%; 217V and +10% 253V) at 3.47kW and 4.05kW. The essential issue of G83 is that the generation is limited to 16A per phase. It is at the discretion of the DNO and they can allow systems up to 10kW under G83.

Be nice.
 
TedM,

I really appreciate the work you've put into this to get these answers

TedM said:
Q3 Can we get clarity as to exactly what the 16A per phase limit for G83 actually relates to? Is it based on:
a) the Declared Net Capacity or the Total Installed Capacity of the system (as given on the MCS commissioning certificate) ?
b) the manufacturers quoted peak output of the PV panels (or other applicable prime mover 'nameplate' figure) ?
c) the maximum grid-tie inverter output?
d) if it is based on the inverter output then is it based on the manufacturer's maximum rating for the model of inverter or based on the (sometimes programmable) actual maximum inverter output figure
e) figures used at a - d above are usually given in Watts - so, in order to convert to Amps, is 230V or 240V to be assumed? I believe the definition in G83 specifically states "230V ac" but many DNOs seem unaware of this minor fact.
f) can you confirm the maximum Watts applicable to a 3-phase supply?

(a) For Inverter systems it is the output of the inverter so it would be possible to install a 3.6kW inverter with 4kW peak of PV panels under G83
(b) No see answer above
(c) Yes see answer above
(d) maximum continues rating
(e) 230 volts is the nominal voltage for the whole of Europe
(f) 230x3x16= 11,040 for practicable purposes this is 11kW, split evenly over three phases. The following is not allowed
phase 1 4kW
phase 2 4kW
phase 3 3kW
as two phases exceed 16A per phase

Unbalance is allowable up to to the following limit
phase 1 3.7kW
phase 2 3.7kW
phase 3 any value under 3.7kW
Click to expand...

I am just quoting a customer for a roof (it's large) which faces just 10 degrees South of East, and he wants to get the maximum possible out of it.

Using PV*SOL, allowing for the orientation and roof slope and using local solar data, it reckons I can put nearly 4.8kWp (panel nominal output) on the roof , and still use a Diehl Ako 4300S inverter - the 4300S has a maximum continuous rating of 16.0A and 3,680W

Based on the reply you got above, do you agree that this should still meet the G83 requirement and therefore be covered by the usual post install process?


Update:
In this case since the output can be no more that 3.68kWp how does that fit in with FITS as the array size nominal is >4kWp, though it is limited by the inverter?


Thanks, Gordon
 
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I had to go and check on the data for the Diehl 4300s inverter and you are right, it's maximum AC power IS 3680w (although this surprises me considering it can take 4.8kWp). Therefore it is acceptable to use this without prior G83 notification.
 

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G83 pre install application
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Solar PV Forum | Solar Panels Forum
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Greenday,
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solarfred,
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