What are the reasons for Bulging in Capacitors?

Bulging in capacitors is caused due to pressure inside the capacitor body. This pressure can be caused due to arcing between the capacitor plates and the resultant generation of gases.

Such capacitors need to be handled carefully. Always contact the capacitor manufacturers on handling or disposing the capacitor units.

Vents are provided in some capacitors as a defence against bulging. Vents need to be periodically checked for rupture which may indicate failure.