A high voltage electromagnetic induction device including: a lead-through device-receiving structure having an opening for receiving a lead-through device, a lead-through device extending through the opening, wherein an internal portion is tapering in a direction along the central axis of the lead-through device away from the opening, and an electrical insulation barrier which is arranged in the lead-through device-receiving structure, arranged around and distanced from the internal portion, and which electrical insulation barrier is tapering in the direction, whereby a duct is formed between the internal surface of the electrical insulation barrier and the external surface of the internal portion of the lead-through device, wherein the electrical insulation barrier is tapering relative to the lead-through device such that the distance between the internal surface of the electrical insulation barrier and the external surface of the lead-through device increases in the direction.