The invention relates to an isolating element for a toroidal core inductor, comprising a first isolating web part and a second isolating web part, which isolating web parts are provided with latching apparatuses which match one another and in each case with at least one retaining projection, wherein the retaining projections, in the mounted state of the isolating element, rest on a respective top side of the toroidal core inductor, and wherein, in the mounted state of the isolating element, the two isolating web parts extend at least in sections into a passage opening in the toroidal core inductor.