This article provides guidance on how New Connections and Initial Registrations are to be managed during the Market-wide Half Hourly Settlement (MHHS) Transition period.

Any New Metering Point that is, or has been, created after MHHS Milestone M10 (22/09/25) will be created under the MHHS arrangements and will have the MHHS Indicator of ‘T’ set within the Electricity Enquiry Service (EES).

The following process should be followed by Suppliers when performing the Initial Registration for these Metering Points, which are referred to as a ‘MHHS New Connection’.

Non-MHHS Qualified Suppliers:

When a MHHS New Connection is registered by a non-MHHS qualified Supplier, the Initial Registration Reverse Migration process will automatically be triggered by MPRS. The Supplier will receive the D0217 ‘Confirmation of the Registration of a Metering Point’ Market Message as per the legacy process and they should continue to follow the legacy Initial Registration process.

For the avoidance of doubt, for Initial Registration Reverse Migrations there is no requirement to populate the ‘REVM’ value in the Service Reference (J0274) or Service Level Reference (J0275) fields in the D0155 ‘Notification of Meter Operator or Data Collector Appointment’ Market Message sent to Meter Operator Agent (MOA).

Once the registration is completed the MHHS Indicator within EES will be updated with a value of ‘R’ and an Effective From Date (EFD) that matches the Suppliers Registration Start Date.

MHHS Qualified Suppliers:

When a MHHS New Connection is registered by an MHHS Qualified Supplier, the MHHS Initial Registration will automatically be triggered by MPRS. The Supplier will receive an IF-002 ‘Notification to New Supplier of Site Information’ (DIP) Market Message as per MHHS processes and the MOA should be appointed using the IF-0031 ‘Supplier Agent Appointment Request’ (DIP) Market Message.

Note: MHHS Qualified Suppliers do not have an option to trade MHHS New Connections under legacy arrangements.

Where the MHHS Indicator EFD has not been previously populated, it would be populated at the completion of the registration with the Supplier’s Registration Start Date.

Note: There is no change to the process for Metering Points created before M10, and these will have the MHHS Indicator set to ‘F’.