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Rota Load Block Alpha Identifiers

Rota Load Block Alpha Identifiers

The rota disconnection process is designed to enable customers to have an equal share of available power across the country on a rotational basis, with protection of certain customers in an emergency situation. The process divides areas of the country into blocks which can be disconnected as needed to reduce demand. An ‘alpha identifier’ is the letter allocated to customers in a particular block by which they will be notified of an intended power cut during a supply emergency. The provision for rota disconnections is included in the government’s Electricity Supply Emergency Code (ESEC) which sets out the procedure the government may take to deal with an electricity supply emergency. The DCUSA sets out how actions will be undertaken by DNOs/IDNOs and Suppliers at a practical level to inform customers of their alpha identifier.


  • By 30 June each year, each DNO and IDNO are to provide the Nominated Central Source with the Alpha Identifier for each Postcode in which they have customers connected to their Distribution System.
  • By 31 July each year, the DNOs/IDNOs are to ensure that the Nominated Central Source will have collated the information provided by the DNOs and IDNOs which will be presented in a (.csv) file format and which shows each relevant Postcode in one column with the applicable Alpha Identifier and MPAS ID in separate columns and that the Nominated Central Source provides it to the DCUSA Secretariat using the method agreed between themselves.


  • From 01 October of each year, each Supplier Party will need to use the information provided on this page by the DCUSA Secretariat to take reasonable steps (to the extent it is reasonably practicable to do so) to notify each of their customers of the Alpha Identifier applicable to that customers Postcode area.
  • Suppliers shall be taken to have complied with its obligation in respect of a particular customer where during the 12-months starting on 01 October each year, the Bills (or statements of account) sent to the customer in respect of the customers property, display the Alpha Identifier in a square box on the front page, and in the uppermost third, of such Bills (where reasonably practicable).

DCUSA Secretariat

By the second Working Day of August each year, the DCUSA Secretariat will have published the collated information on the DCUSA Website, in a .csv file format, and will issue a notification to DCUSA Parties that the information has been published.


  • Alpha Identifier: means the single letter assigned to each Postcode area covered by the Company’s Distribution System for the purpose of identifying (insofar as reasonably practicable) the Load Block with which Customers in that Postcode area are associated.
  • Bill: has the meaning given to that term in Condition 1 of the Supply Licences.
  • Electricity Supply Emergency Code: means the code of that name designated as such by the Secretary of State from time to time.
  • Load Block: means a geographic grouping of consumer load for the purpose of applying rota disconnections, as such rota disconnections are more fully described in the Electricity Supply Emergency Code.
  • MPAS ID: means the unique two-digit number by which MPAS Providers are identified.
  • Nominated Central Source: means a person agreed between the majority of DNO/IDNO Parties for the purpose of Paragraph 13 of Schedule 8 of the DCUSA.
  • Postcode: means the full Post Office postcode (outcode and incode) of up to 8 characters, which will be presented with a space between the outcode and the incode (and no other spaces).
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