An extension cord is a short term solution for supplying power outside, but a longterm solution will require running wire underground and installing a GFCI outlet. A GFCI outlet or Ground Fault Circuit Interrupter should be installed anywhere an outlet will be exposed to moisture to protect the user from electrical shock. Electrical wire installed underground must be encased in a metal sheathing or duct that is welded to ensure a continuous run, meaning there are no gaps or leaks. Metal boxes and fittings are installed to connect the wiring to the appliances or buildings it will power.