Many self-healing polymers require elevated temperatures for healing. Curie temperature (TC) controlled magnetic nanoparticles can generate heat through the application of an external alternating magnetic field (AMF). Thus, heating can be localized and regulated, preventing damage to the polymer due to high temperatures. In this work, novel TC controlled magnetic nanoparticle filler–polymer matrix composites (Magpol) were investigated as wire insulation materials. Mn–Zn ferrites were introduced as the filler in a thermoplastic polyethylene vinyl acetate (EVA) matrix. The composite was subjected to different damage modes, such as chaffing and tear. Greater healing efficiency was obtained at lower filler loading compared to other relevant systems. Efficient healing was obtained without any thermal degradation. Good agreement was observed between experimental results and theoretical models of polymer healing. Thus, a Curie temperature controlled magnetic nanocomposite system was developed with improved self-healing capabilities.