This paper provides an overview of the electrical insulation of high temperature superconducting fault current limiter (HTS FCL) by singling out from the literature a few aspects that are critical for such insulation. The performances of some important insulating materials such as organic polymers with fillers, non-filled ethylene propylene rubber (EPR), polyimide and epoxy nano-composites are reported. The main elements of the electrical design and withstand tests of mini-model coils are described. Moreover, as practical applications of such concepts, the paper illustrates the electrical insulation design of a 13.2 kV/630 A bifilar winding type HTSFCL with YBCO coated conductor (CC) wire and of a cryogenic bushing for superconducting power applications.