A power outage left nearly 500 Bronx residents without fans or air conditioners on one of the hottest days of the summer.The outages are scattered throughout the borough, many in Longwood. Officials from Con Ed say two manholes exploded Monday night causing feeder cables to catch fire. They are not sure, however, what caused the explosion. Meantime, Con Ed customers who want to report a power outage or apply for reimbursements for spoiled food should call 1-800-752-6633.