Electricity Running Through Wire Creates Electromagnetic Field
"When an electrical current flows in a wire, the movement of the electrons produces a similar field in space, but one that is oriented around the wire. If the current is a DC (direct current), the magnetic field is steady, like that form a permanent magnet. The strength of the magnetic field depends upon the amount of current flowing in the wire--the more current there is, the stronger the magnetic field will be. If the current in the wire is fluctuating, the magnetic field will have the same fluctuations." (http://tuberose.com/Electromagnetic_Fields.html)