A method and apparatus for the coating of running strands on webs with a thermoplastic protective layer. The successive steps comprise the application of a primer and the air current drying and curing of same using inductive heating. While still hot, the strand or web is passed axially through a dense cylindrical bed of a powdered thermoplastic. This bed is constantly being cooled and replenished by recycling using air currents and directional jets. Vinyl polymer, epoxy-polyamide, and polyolefins such as polyethylene or polypropylene containing metals, metal oxides, metal hydroxides and metal carboxyl groups are proposed as coating materials.