Rated current (In) 20 A vs frame rating (Iu) 160 A — the sizing decision
The 1SDA068094R1: This is the value that matches the load circuit — a 20 A feeder, motor branch, or distribution subfeed. The frame rating Iu is 160 A, meaning the physical breaker shell and bus bars are rated for up to 160 A. The TMD thermal-magnetic trip unit is adjustable from 20 A up to 300 A (the TMD 20-300 designation), so the same frame can be re-set for a higher load by swapping the trip unit — useful if the panel design changes later. At 20 A In, this breaker sits in the ABB XT4 platform — a compact 160 A frame size that fits standard distribution panelboards and switchgear. The 4-pole configuration handles three-phase plus neutral, common for 3-phase 4-wire systems in commercial and industrial distribution.