The DCUSA was originally established as a multi-party contract between all licensed electricity suppliers and licensed electricity distributors in England, Wales and Scotland.
The DCUSA was created to replace a large number of bilateral agreements that had previously provided the legal context for suppliers to use distribution networks in order to supply power to their customers, and for distributors to levy use of system charges on suppliers.
The scope of the DCUSA has crept significantly in recent years, to the point that only about half of the DCUSA document now provide for the legal relationship between distributors and users of their distribution systems.
The rest of the document reflects the (ab)use of DCUSA as a vehicle to provide for the publication and governance of regulatory documents which have no contractual force between the parties, but which have legal effects on DCUSA parties and on non-parties (such as electricity end users) through their interaction with statute or licences.
The DCUSA includes the following (page counts are for version 5.9 of the document, dated 27 June 2013):