Peco says it has completed investigations of six of the 15 incidents and suspects the overheating is caused by "pre-existing" problems with the wiring in houses connected to the meter, not with the smart meter itself.
Utilities worldwide are aggressivly swapping their old meters for smart meters, which allow for two-way communication with customers and are a critical component in upgrading the electrical grid. Fires, which utilities have blamed on faulty wiring in the homes, have been reported in Florida, California, British Columbia and Australia.
But the incidents are likely to provide ammunition to opponents of smart meters, who fear health problems are caused by the radio waves emitted by wireless meters, and are concerned about loss of privacy because of the voluminous data that utilities can collect from the meters, which take readings hourly.
"Certainly it's something we're paying attention to," said Don Kintner, a spokesman for the Electric Power Research Institute. But he said the institute has done no research on the subject.
In the most recent incident, fire officials in Upper Makefield Township on Sunday morning extinguished a blaze that originated from a recently installed meter on a house in Washington Crossing. A neighbor heard a pop and saw sparks and flames shooting out of the meter box of the house on Lookout Lane.
Peco is aware of the danger of an electrical fire associated with faulty wiring. During the meter installation process, technicians wear fireproof clothing and heavy gloves to protect them from a short circuit as they pull the old meter out of a socket and insert the new meter in its place.
The meters are affixed to a board whose maintenance - along with the wiring inside the home - is the responsibility of the homeowner.
"If we see there's a problem with customer equipement, Peco has been repairing it where it's visible," said Engel Menendez.
Peco is installing 600,000 new meters by next year - it calls the devices AMIs, for "advanced metering infrastructure" - as part of a $650 million program to upgrade its distribution system. The effort is supported by a $200 million U.S. Department of Energy grant.
Engel Menendez said the overheated devices were all Sensus brand meters. The utility will replace some Sensus meters with another brand, L&G, to test if the device itself plays a role in the malfunctions, she said.
Because it can communicate remotely with the meters, Peco is changing the software so that the meters will shut down automatically and emit an alarm if an electrical problem is detected, she said. The upgrades will be installed beginning Aug. 26.
The new meters, which Pennsylvania is requiring for all large electric utilities, allow for two-way wireless communication with customers, setting the stage for time-of-use pricing next year. They also will improve utilities' ability to detect and manage outages, as well as to turn on or shut off customers remotely.
Customers with concerns about their smart meters can call Peco at 855-741-9011 and the utility will dispatch a technician to inspect it, Engel Menendez said.
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