Transformer-protection circuit breaker, size S00
The 100 kA breaking capacity holds at 240 V, 400 V, 500 V, and 690 V AC — a flat curve that simplifies selectivity studies. At 690 V the gL/gG fuse backup is 6 A, which is the fuse rating, not the breaker's own interrupting rating. For a transformer secondary fault, the breaker's own 100 kA at 400 V covers most industrial service-entrance scenarios without an upstream fuse.
Panel integration and clearances
Depth is 97 mm, matching the S00 frame height. Side clearance required is 30 mm; top and bottom each need 50 mm. Zero clearance forward and backward — the breaker can sit flush against a gland plate or back panel. Screw-type terminals on the main circuit accept 2× (0.75 to 2.5 mm²) solid or stranded, or 2× 4 mm². The screwdriver shaft diameter is 5 to 6 mm, and the main contact screws are M3.
