The solar panel will have a port that allows a D/C cable to connect to it. That cable, which is inexpensive, transmits the power generated by the solar panels to the power inverter. The exact cable model will depend on the brand of panels and inverter.
Once the D/C power reaches the power inverter, the inverter converts it to a usable, 120-volt format for a household. The power inverter has a 120-volt outlet into which the extension cord is plugged. Power inverters vary in price, depending on the features offered.
Connect the solar panel's D/C cable directly to the breaker of a home. This is useful for large-scale solar panels or multiple panels. The breaker will convert the power into a usable format for the extension cord. If this method is used, then the extension cord can be plugged into any outlet associated with the breaker. The exact method of connection will depend on the type of breaker used. Newer breakers may have a D/C input port, specifically for "green" power. On older breakers, the solar panel may need to be connected with the main line. If that is the case, a licensed electrician must make the connection.
Some solar panels are ready-made for outlets. That is, the solar panel comes with a built-in power inverter and outlet. Purchasing such a panel is by far the simplest method for connecting an extension cord to a solar panel. It requires no special wiring, and setup takes minutes.