A mounting device for mounting a capacitor on a connector element includes a hollow body defining a continuous through-hole that axially penetrates the body for receiving and mounting the capacitor. The body has a lower region defining a lower through-hole portion with a dimension. The body further has a middle region defining a middle through-hole portion with a dimension that is smaller than the first through-hole dimension. Therefore, the middle region and the lower region define a first inner shoulder between them. The body further has an upper region defining an upper through-hole portion with a dimension that is smaller than the second through-hole dimension. The upper region and the middle region define a second inner between them.