Take, for instance, the way that certain substances produce light when current passes through them. Below a given threshold, no light is emitted. Above that, the atomic shells are sufficiently energized and photons are ejected. This process does not in and of itself lead to any subsequent damage to the material. However, if too much current flows then the atoms can become so energetic as to disassociate with their neighbors and change state (melt). Perhaps the same is true of the avalanche breakdown effect of capacitors; as long as the combined current and voltage does not exceed a certain maximum, no harm done.