A £2 million fine has been imposed by energy regulator Ofgem on EDF Energy Networks for poor customer service.
Following a three-year investigation into connection times it was found the company's customer services standards were "poor", and they failed to offer connections quickly enough to homes.
Ofgem found EDF had taken steps to improve its connections service but this should have been done earlier.
"Customers should not have to accept poor service in any part of the energy market," Sarah Harrison, Ofgem's managing director said.
"All energy companies should be in no doubt that if they are failing to offer good service Ofgem will take tough regulatory action."
Despite a warning from the watchdog in 2006, EDF Energy Networks failed to meet the three-month deadlines to make offers for those seeking connection to the network, on many occasions.
Ofgem also found it did not have systems in place to judge if it was meeting the three-month rule.
The regulator said it would have received a higher fine, had EDF not already paid out £450,000 compensation to affected customers.
EDF distributes electricity to 7.8 million customers in the south and east of England, where it operates and maintains the electrical supply system.
A statement from the company read: "EDF Energy Networks is committed to achieving the highest standard of customer service.
"Therefore, the company greatly regrets the delays previously experienced by some customers in the provision of timely information regarding connection to its network during the period April 2006to November 2008."
(JM/BMcc)
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