Siemens 5SL4332-0RC Miniature Circuit Breaker 32A 3-pole Z 1

The Z trip curve is designed for semiconductor protection and other sensitive loads where the inrush current is minimal but short-circuit protection must be fast — it trips between 2.5 and 4 times rated current, so a 32 A unit clears faults in the 80–128 A range before downstream electronics cook. The Z curve is less common than B, C, or D in general distribution panels, so if you are restocking a bin for a line that uses these on control transformers or rectifier feeds, this is the right code — a C-curve 32 A would pass a higher inrush and may not clear a semiconductor fault fast enough.