Abstract: An electrochromic device is disclosed. The electrochromic device includes (i) a first substrate with an electrically conductive layer on an inner surface thereof; (ii) a second substrate with an electrically conductive layer on an inner surface thereof; (iii) an electrochromic assembly comprising at least one electrochromic layer; (iv) a first bus bar pair comprising a positive bus bar electrically connected to the electrically conductive layer of the first substrate and a negative bus bar electrically connected to the electrically conductive layer of said second substrate; and (v) a second bus bar pair including a positive bus bar electrically connected to the electrically conductive layer of the first substrate and a negative bus bar electrically connected to the electrically conductive layer of the second substrate. A process for reversibly changing the optical properties of an electrochromic device that includes at least one electrochromic layer is also described.