Deputy Fire Marshal James Tarzia said a resident reported seeing a fan on fire in a second-floor bedroom after a smoke detector went off Wednesday afternoon. When the fan crashed on the floor, he said the blade could have jammed and caused the motor to short out and ignite the fire. Spaulding said power strips are safe for computers, routers and cellphone chargers, but appliances like air conditioners or fans should be plugged directly into wall sockets.