Busbar-mounted DOL starter, 15 kW at 400 V
The 3RA2120-4NH27-0AP0: It snaps onto 60 mm busbar systems via the supplied busbar adapter (8US1251-5NT11), not a DIN rail — the mounting foot is built for the busbar profile, so panel layout needs that clearance. The assembly ships with the contactor (3RT2027-2AP00), the thermal bimetallic overload relay (Class 10), and the circuit-breaker (3RV2021-4NA20) pre-matched — one order code, one BOM line, no separate sizing.
Dimensions and panel fit — vertical mount only
The starter measures 45 mm wide, 260 mm high, and 165 mm deep — the width fits a standard 45 mm busbar slot; the height and depth demand vertical mounting with 50 mm clearance above and 20 mm in front for terminal access and cooling airflow. Side clearance is 20 mm; no clearance needed behind (0 mm backwards). Operating temperature range is -20 to +60 °C, storage -50 to +80 °C — fine for most industrial enclosures; derate if ambient exceeds 60 °C.
Protection and trip coordination
The thermal bimetallic element tracks motor heating; the magnetic short-circuit trip in the breaker handles fault clearing. Rated insulation voltage is 690 V, so it works on 400 V, 480 V, and 690 V line systems. The operating frequency is 50/60 Hz — global line compatibility without derating.