Danger Potential
Electricity flows whenever there is a difference in voltage between two points.
It is dangerous to touch these two points because you may complete the circuit and get a shock.
The one-hand rule says to only use one hand when touching electronic equipment. In this way you will not place your heart in the middle of a circuit.
If an outlet has faulty wiring, the difference in voltage could cause electricity to flow between UTP cable and the computer case.
UTP cable is copper and copper is a conductor.