(STMW) —  Three of ComEd’s new digital smart meters have overheated and caused fires in customer’s homes, the utility said Thursday.

The announcement comes two weeks after a Philadelphia utility under the same ownership as ComEd stopped installing smart meters after one of them set fire to a home and 14 other devices overheated.

ComEd said the problem in Chicago is not with the smart meters, but in the way they were connected to the customer’s wiring.

“The cause was related to fitting and connection issues with an older-model socket that had a poor connection at the point where the customer’s wires and ComEd’s wires meet,” ComEd said in a statement.

All three smart meters involved in the fires were installed in the same type of socket, ComEd said.

The fires occurred in River Forest in 2010 and 2011 and Berwyn in 2012, the utility said.

The smart meters ComEd is using are a different model than the ones used in Philedelphia by PECO, a company owned by ComEd parent Exelon.

Nevertheless ComEd said it is “taking advantage of the lessons learned at PECO and taking additional measures for the benefit and safety of our customers.”

Those measures include performing daily remote temperature scans on all 130,000 installed smart meters to identify devices that may be overheating.

Also, installers in the future will modify the connection sockets when needed. The utility said this will not increase its costs.

Smart meters have radio transmitters that allow for two-way communication between the utility and the meter.

The meters can record and transmit temperature data and alert the utility when outages occur.

The new meters also allow the utility to charge different rates for peak and off-peak usage.

They were installed in 130,000 homes in Chicago’s Humboldt Park neighborhood and 10 western suburbs as part of a pilot program approved by the Illinois Commerce Commission in 2009.

Last year, the state passed a “Smart Grid” law allowing increased electric rates to pay for more meters and other grid improvments. But ComEd said the ICC didn’t raise rates high enough, and has asked to delay more smart meter installations scheduled for next year.

All ComEd customers are supposed to get the new meters over the next 10 years.

The Smart Grid could benefit consumers if implemented correctly, said David Kolata of the Citizens Utility Board.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2012. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)