The DF3FN40 is a 40 A NFC cartridge fuse from the TeSys fuse-disconnector range, sized 22 x 58 mm with a gG (general-purpose) characteristic. It carries a striker for local visual indication — when the fuse element clears, the striker pin pops, giving a clear blown-fuse flag at the panel without needing a separate indicator lamp. The 690 V AC rating covers standard 400 V three-phase distribution and motor branch circuits without derating concerns.
Rated 40 A at 690 V AC, this fuse is sized for motor feeder and distribution branch protection where the gG curve provides overload and short-circuit clearance without nuisance opening on motor inrush. The 22 x 58 mm body is a standard European fuse-link size — fits existing NH-style fuse holders and disconnect switches in the TeSys GS range. The striker pin (local signalling) trips an auxiliary contact or simply flags the blown state at the fuse holder; if your panel relies on remote blown-fuse indication, confirm the holder has the mating microswitch.