It is generally thought that, when direct current flows in a stationary wire, no external electric field is produced. However, we show that if the Lorentz contraction of the assemblage of moving electrons is taken into account, special relativity theory predicts a nonzero electric field. Other theory also predicts nonzero electric fields through other mechanisms, and experimental works report confirmation of these mechanisms.

Keywords: Special Relativity, Electromagnetism, Electromagnetic Theory