Cracked Glass Seals Can Initiate Breakdown Outside a Protection Diode

What the evidence preview establishes

Electrical breakdown occurred outside the diode bodies at the potting-to-glass-seal interfaces. Cracked diode seals were the most significant fabrication anomaly and likely promoted the failures.

Why this case matters

When a potted protection module arcs, trace the damage path backward rather than treating every melted phase as causal. Seal cracks can retain contaminants and create a vulnerable external interface even when the diode die survives.