The contract is valued at £28.5m in total and has the option of a three-year extension.
Commencing in November 2010, the contract covers both planned and emergency works across South Wales, involving the delivery of excavation, cable laying and reinstatement works for both low voltage and high voltage networks.
Balfour Beatty Utility director of electricity Tony Scott said that technical capability and service excellence are key to the successful delivery of this contract.
"We have worked closely together to achieve a two-hour response time to emergency fault works, which make up 40% of all work instructions," Scott said.
