Pg & e officials have reported a defect with some of the recently-installed smart meters. Some of the meters can overcharge customers, if the devices get too hot. Pg & e says about 16-hundred wireless meters are affected, in northern and central california. The devices can mis-read usage, if they reach a temperature greater than 100 degrees. Pg and e plans on replacing any defective meter that has not already been replaced, and expects to send refunds to customers who were overcharged.