A fire investigator says a fire that ripped through a single-family house in Waipahu Sunday night was caused by a malfunctioning electrical outlet. The fire was reported at about 9 p.m. on Lumi Place. Firefighters quickly controlled the flames and extinguished the fire within minutes. But, it had caused an estimated $150,000 damage. No one was injured and the Red Cross assisted the eight people who were displaced.