What lands on the BOM line
The ABB 1SAZ431201R1003 is a solid-state overload relay in the Circuit Breakers, Fuses & Protection family, sized to the 135 A current class and sold under ASEA BROWN BOVERI legacy branding on the part label. It sits in the Solid State Overload Relays sub-category, which puts it next to the motor-protection devices used to trip a contactor when running current exceeds the setpoint — not a breaker, not a fuse, but the electronic element behind the heater socket.