Panel fit and what the ratings mean
The 3RA2120-1FE24-0AP0: The Class 10 trip characteristic means it will hold starting current long enough for a standard induction motor to accelerate (typically 5–10 seconds at locked-rotor) but trip fast on a sustained overload. That matters when you're coordinating with upstream protection: a Class 10 starter lets you set the motor branch circuit breaker tighter than a Class 20 would. Rated maximum operating voltage is 690 V in AC-3 duty — that's the switching voltage for motor loads, not just the insulation rating. The contactor inside is a 3RT2024-2AP00, paired with a 3RA2921-2AA00 link module that ties the overload relay to the contactor mechanically and electrically.
Mounting and clearance — what fits where
Width is 45 mm, depth 107 mm, height 243 mm. It screws down or snaps onto 35 mm standard mounting rail — the snap-on foot is the same profile as the SIRIUS contactor range, so it shares the rail with other S0 devices without adapters. Mounting position is vertical only; if you lay it on its side the bimetal overload won't track ambient correctly. Clearance requirements: 50 mm upwards, 20 mm forwards, 20 mm at the side, 10 mm downwards, zero backwards. The zero backwards clearance means it can sit flush against a back panel or gland plate — useful when you're packing multiple feeders into a shallow enclosure.
That simplifies MRO stock planning: one starter SKU plus the individual contactor and overload as line-replaceable units.