What the 40 A TM-D trip unit means for your BOM
That 40 A is the full-frame rating for this NSX100F frame, so you get the full interrupting capacity of the frame at this trip size. At 240 V AC it delivers 85 kA Icu — enough for most North American panelboards fed by a large transformer. At 415 V AC, where most European industrial distribution runs, it delivers 36 kA Icu. The breaker is 4-pole (4P) with the neutral on the left. Neutral protection is set to 3D — no protection on the neutral pole, meaning it switches the neutral but does not trip on a neutral overload. That is standard for distribution where the neutral is not expected to carry fault current. The toggle control is manual, no motor operator included.
Connections are front-facing on both the line and load sides, which simplifies busbar connections and cable dressing in a panel.
Durability and electrical life
Mechanical durability is 50,000 cycles — the number of on-off operations the mechanism can handle before wear. Electrical durability varies with load: 50,000 cycles at 440 V at half rated current, 30,000 cycles at full 40 A at 440 V, and 10,000 cycles at 690 V at full current. For a distribution breaker that operates infrequently (a few times a year for maintenance isolation), this is more than adequate. For a breaker that cycles daily with a load, the 10,000-cycle figure at 690 V is the limiting factor.