If an electrical outlet is warm to the touch, it means that there is likely a short circuit in one of the wires. A short circuit occurs when electricity skips some of the path it was intended to take in the circuit design. When this happens, it creates excess heat that the wires and terminals are not designed to handle.
An overheated outlet can also be caused by an appliance attempting to draw too much power. Normally, each electrical circuit is rated for 15 to 20 amperes shared between all outlets on that circuit, according to the University of Texas. Heavy-duty appliances such as washers or dryers take up more power. In case of overload, the circuit breaker usually trips, or the fuse breaks, but it's not safe to just rely on the circuit breaker. Wires can burn or melt from electrical overload before the breaker detects the excess current and acts. Too much electricity flowing through a circuit creates heat because of the friction generated by electrons as they travel through the wire.
If you discover an outlet is hot to the touch, unplug any appliances from it, shut down the electrical circuit immediately and call an electrician to check the wiring. To shut off power to a circuit, access the circuit breaker panel in your home and flip the associated switch.