What causes capacitors to explode?

All capacitors have a maximum voltage and their destruction depends upon the internal construction. Explosions are understood only by delving into the internal construction of electrolytic capacitors - the primary culprit. read more

Even if the capacitor plates were able to survive the negative voltage for a short time the effective AC impedance of a 100uF capacitor connected to the AC mains without many other series components to limit the current would result in a goodly amount of power being dissipated in the component resulting in the sealed can expanding and exploding. read more

In electrolytic capacitors heating can cause the formation of gas inside which can explode through the vent provided. Voltage surges can also cause capacitor failure. Overtime, capacitors re-form themselves to a particular voltage. read more