Power line transformers can fail or «blow» due to faults and overstress. Common causes include lightning strikes, severe short circuits causing mechanical forces and overheating, insulation breakdown from aging or moisture, overloading beyond thermal limits, oil degradation, or internal winding faults. In overhead distribution, animal contact or contamination can lead to flashovers at bushings. When a failure is violent, rapid pressure rise in the tank can cause ruptures or operation of pressure relief devices, sometimes with visible flames. Proper protection, surge arresters and maintenance reduce these risks.