When the new Part 10 and associated amendments to Parts 1, 11 and 15 (new metering rules) were implemented, it was identified that half-hour (HHR) certified and reconciled advanced metering infrastructure (AMI) metering installations created issues for the process used to switch ICPs between traders.

To overcome these issues, and so enable the new metering rules to function as required, a new switch completion file (known as the CS file), and Code amendments for ICP switching were included in the Part 10 implementation project. The intention was that the switching process would be fully reviewed after the new metering rules came into effect and participants had some experience with switching HHR AMI metering installations.