Revision 41217 of "Ground_loop" on enwiki

'''Ground loop''':  In an electrical [[system]], an unwanted current that flows in a conductor connecting two points that are nominally at the same potential, <i>i.e.,</i> [[ground]], but are actually at different potentials. 

<i>Note 1:</i>  For example, the electrical potential at different points on the surface of the Earth can vary by hundreds of volts, primarily from the influence of the solar wind. Such an occurrence can be hazardous, <i>e.g.,</i> to personnel working on long grounded conductors such as metallic telecommunications [[cable]] pairs. 

<i>Note 2:</i>  A ground loop can also exist in a floating ground system, <i>i.e.,</i> one not connected to an Earth ground, if the conductors that constitute the ground system have a relatively high resistance, or have, flowing through them, high currents that produce a significant voltage ("I&middot;R") [[drop]]. 

<i>Note 3:</i>  [[Ground]] loops can be detrimental to the [[operation]] of the electrical [[system]]. <i>Contrast with</i> <b>[[ground current]].</b>

Source: from [[Federal Standard 1037C]]