  It is well known that electric and magnetic fields may change when they are
observed from different frames of reference. For example, the motion of a
charged probe particle moving parallel to a current-carrying wire would be
described by utilizing different electric or magnetic fields, depending on from
which frame of reference the system is observed and described. To describe the
situation in all frames by utilizing the theory of relativity, one has to first
describe the situation in one particular frame, and this choice in the case of
a current-carrying wire is the topic of this paper. In this study I examine an
alternative to the standard choice, and consider its theoretical and
experimental validity. An outcome of the alternative approach is that in the
rest frame of a wire, running a current introduces also an electric field by
giving rise to a minute charge. Present day experimental sensitivities,
specifically those of cold ions, may be able to differentiate between the
observable signatures predicted by the different approaches.
