Homes built between 1965 to 1972 may have aluminum wiring in them. Aluminum wiring was used more prevalent during a period of time of high copper prices. It was determined that aluminum was a great alternative, however after a number of years it became determined that aluminum would expand and retract with loads of power, and loosen connections. This caused a number of home fires and became a known safety hazard that caused thousands to lose their homes or lives.
Common signs of aluminum wiring include hot electrical outlet face plates, burning plastic smells near electrical outlets or light switches, flickering lights, or failed electrical outlets. Anytime you have any of these types of indications you should contact a certified electrical contractor to come evaluate the electrical system.