Electrical device comprising a PTC polymer element for overcurrent fault and short-circuit fault protection

摘要

The invention relates to an electrical device with a PTC polymer element having a constriction. The constriction defines a web extending in a main current direction over a length longer than in the prior art, namely longer than 5 mm, preferably longer than 15 mm. Further, the aperture angle of the PTC polymer material at the ends of the web is larger than 100°. A preferred choice of material is given, further. The invention achieves very high voltage-withstand capabilities.