Around 130,000 homeowners are in arrears on their ESB bills, new data has revealed.
A further 310,000 cash-strapped families have agreed to payment plans in order to ensure the electricity to their homes is left on.
The news comes after Electric Ireland revealed they have appointed a British debt-collection firm to chase down unpaid bills.
They have brought in UK-based BCW to take over its payment-collection operations for its 1.3 million customers.
An Electric Ireland spokesman insisted, however, that customers would be treated no differently under the new system than they were before.
Around 200 families a month are being disconnected because of their failure to pay electricity bills but Electric Ireland insists they have a lower level of disconnections than its main rivals, Bord Gais and Airtricity.