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?
