Electrical transport properties of luminescent silicon nanocrystalline films are reported. These films are obtained by ion-gun ablation of a composite target of silicon and insulator (silicon dioxide). Structures metal/nanocrystalline (granular) silicon/p bulk silicon (MGS) are employed to measure the conduction across the film, as a function of the absolute temperature in the range 20-300 K. Despite the fact that the film behaves as an insulator in the plane of the film, MGS structures, with thin layers of granular silicon, showed good conduction. A general theoretical interpretation, based on a tunnelling model through silicon nanocrystals, is used to give a good interpretation of the experimental results.