337 / | HD | ELECTRICITY: ELECTROTHERMALLY OR THERMALLY ACTUATED SWITCHES |
14 | DF | ELECTROTHERMALLY ACTUATED SWITCHES {9} |
15 | DF | .~ Shunt or short circuit completion devices {4} |
17 | .~.~ Fusible material combined with gap {1} | |
18 | DF | .~.~.~> Gaseous space discharge gap (e.g., air gap) |