Upper terminal — attaches to spring-and-cable assembly
Stainless-steel auxiliary arcing rod
Silver-clad copper main arcing rod
Solid material arc-extinguishing medium
Filament-wound glass-epoxy tube
Large-diameter stepped portion of auxiliary bore — delays arc extinction until sufficient gap is attained to preclude reignition
Fusible element — helically-coiled silver or pretensioned nickel-chrome — provide precise melting characteristics and nondamageable perfomance