An insulated glazing unit can include a spacer frame disposed between a first substrate from a second substrate and forming a portion of a sealed boundary and a flexible circuit extending through the sealed boundary. In an embodiment, the flexible circuit includes a flexible ribbon having a total length, LA, and an effective length, LE, and wherein LE is less than LA. In another embodiment, the flexible circuit includes an expandable portion adapted to expand a length of the flexible circuit to accommodate: relative movement between two or more portions of the insulated glazing unit, resizing of one or more portions of the insulated glazing unit, or any combination thereof.