Abstract: A retaining clip for releasable fixing of a plurality of modules strung together on a distributor bar for forming a module series, wherein the distributor bar has a substantially U-shaped cross-sectional geometry with two legs as well as a back wall and the two legs, have a plurality of recesses. The retaining clip has a substantially U-shaped cross-sectional geometry with two retaining clip legs as well as a connecting bar between the two retaining clip legs, whereby the two retaining clip legs each have at least one detent, which may be brought into locking engagement from the outside into respectively two opposite recesses of the distributor bar, such that the retaining clip may be snapped onto the distributor bar for securing the modules of the module series from lateral displacement in the longitudinal direction of the distributor bar with this.