1. Implementation of Non Effective Days Nexus Workgroup – March 2015 1

2. Modifications Two UNC Modifications have been raised requesting non effective days 0532 - Implementation of Non Effective Days (Project Nexus transitional modification) 0535 - Implementation of Non Effective Days to enable Annual AQ Review (independent of Nexus transition) 2

3. Non Effective Days - Definition Non effective days are defined for each instance in which they are required. Previous non effective days have had the following principles: Non effective days constitute UNC non Business Days but with the following additional features: No communication (under the Code or any other contract between Transporter and a User) pursuant to which Transporter would be required to to revise the Supply Point Register, may be made No Supply Point Confirmations can be submitted or become effective No communications (under Code or other contract) would be required to be processed by the Transporter to revise the Supply Point Register DM Liability Relief 3

4. Relationship between 0532 and 0535 Modification 0532 proposes non effective days around Project Nexus Implementation Date (PNID). [Five]^ non effective days preceding PNID are required PNID is 1 st October 2015 Modification 535 asks for [two] fixed non effective days – [i.e. 29 th and 30 th Sept 2015] IF Project Nexus Implementation Date is changed the requirement for non effective days envisaged by 0535 will be required. Raising 0535 now mitigates the risk of a late or urgent modification It is likely that the non effective day definition for 0532 will be [slightly] more onerous than 0535 0532 will take precedence where the two periods are coincident ^ - This reflects current understanding of required implementation timings 4

5. Non Effective Days - Benefits ‘Non effective days’ have been used around significant system implementations in the industry to reduce the associated risks by: Allowing ‘business as usual’ activities to conclude without risk of data corruption Facilitating migration - allowing validation on source and target on stable platform Allowing greater certainty on timings and reduced complexity of cutover Allowing resources required time for cutover activities and releasing existing system support resources to assist 5

6. UNC Modification 0535 – Implementation of Non Effective Days to enable Annual AQ Review Nexus Workgroup – March 2015 6

7. Background UNC Modification 0477 ‘ Faster Switching’ reduced the timescales of the change of shipper process. One way that this was achieved was to reduce the period between the Objection Deadline and the Supply Point Registration Date (referred to as the ‘confirmation period’) from 7 to 2 Business Days. These days allow Users and the Transporters certainty that a change of shipper event is confirmed. For example: Users may request meter readings to be obtained for the Supply Point Registration Date Transporters use this time period to collate the relevant data and propagate this around UK Link systems 7

8. Why Change? During the Annual AQ Process every Supply Meter Point AQ is updated. These AQs are updated to UK Link systems and made effective from 1 st October each year. The AQ data must be correctly associated with the relevant Registered User to ensure that it is attributed correctly. Previous AQ Reviews have taken 5 days to upload the data, associate to the User, validate and provide this data to Gemini. Prior to 0477 this process could start at D-7 (business days). Following 0477 the User will not be confirmed until D-2. 8

9. Solution In order to provide sufficient time to process and validate the data it is proposed that [two] non-effective days will be required. The non effective days will have the effect of extending the ‘confirmation period’ so that the Objection Deadline will be no later than Friday 25 th September. The non effective days will apply only to UNC Section G and M processes – e.g. SPA transactions RGMA transactions Meter Reading transactions 9

10. 535 Non Effective Day Detailed Solution Contrary to previous definitions of non effective days Propose that Supply Point Confirmations MAY become effective on these NEDs Proposed to continue to issue DM Readings to Users Consistent with previous definitions of non effective days No communications (under Code or other contract) would be required to be processed by the Transporter to revise the Supply Point Register Note: this definition appears to be consistent with a Non Supply Point System Business Day other than under these NEDs PREFER that Code and other communications are NOT issued** Code comms could be processed in ‘catch up’ if necessary** ** - Only relevant to 0535 10

11. UNC Modification 0532 – Implementation of Non Effective Days (Project Nexus transitional modification) Nexus Workgroup – March 2015 11

12. Background Transition from Current to New UK Link Systems presents significant challenges As detailed above, ‘Non effective days’ have been used around significant system implementations in the industry to reduce the associated risks by: Allowing ‘business as usual’ activities to conclude without risk of data corruption Facilitating migration - allowing validation on source and target on stable platform Allowing greater certainty on timings and reduced complexity of cutover Allowing resources required time for cutover activities and releasing existing system support resources to assist Also, new business requirements require that new data be propagated around existing UK Link Systems – i.e. Gemini 12

13. Solution It is proposed that [five] non-effective days will be required. These [five] days are proposed to be [three] days that would have otherwise been classified as Business Days [28 th – 30 th September 2015], and [two] days that would have otherwise been Non Business Days (NBDs) [26 th /27 th September]. [26 th / 27 th September] are included as NEDs rather than NBDs as the system will not be brought up on Monday 28 th to process any Code communications received over the weekend The non effective days will apply only to UNC Section G and M processes – e.g. SPA transactions RGMA transactions Meter Reading transactions 13

14. Solution Planned implementation start on [26 th September] Implementation activities planned right through until 1 st October Full revision of data to other UK Link Systems, due to: Change in data – i.e. additional Supply Meter Points – e.g. iGTs Change in requirements – e.g. Gemini data split by Class Validation of this data will be harder than normal non Gemini to Gemini data load (described in 0535) as first live run of data Data validation Data sequencing – ensure that UK Link Systems will have consistent data where sequenced – e.g. next MPRN creation File sequencing – set next file by User … and applying the revised AQs to New UK Link Systems 14

15. 532 Non Effective Day Detailed Solution Contrary to previous definitions of non effective days Propose that Supply Point Confirmations MAY become effective on these NEDs Proposed to continue to issue DM Readings to Users Consistent with previous definitions of non effective days No communications (under Code or other contract) would be required to be processed by the Transporter to revise the Supply Point Register No communications (under Code or other contract) pursuant to which Transporter would be required to revise the Supply Point Register may be made Note: this definition appears to be consistent with a Non Supply Point System Business Day other than Code and other communications may not be issued ++ Consistent with 0535 ++ Not Consistent with 0535 15

16. Summary Largely consistent definition proposed between 0532 and 0535 non effective days 0532 proposes that communications are not made Any files received after close of processing on [25 th September] will be discarded Users may receive receipting and delivery receipts inferring processing 0535 requests communications are not made Only relevant if 0535 is not coincident with 0532 non effective days – but files received would be processed as a catch up exercise 16