CBM circuit breakers protect a group of 24 V DC load circuits in one module-CBM E4 in a four-channel version and CBM E8 in an eight-channel version. Rated current for each channel is set in steps of 0.5, 1, 2, 4, 6 and 10 A. Maximum total input current of CBM E4 is 40 A. CBM E8 accepts up to 80 A, but only with a dual IN+ input supply using conductors of at least 2 × 6 mm². Both modules are 41 mm wide, 130 mm high and 121 mm deep, have efficiency above 99%, IP20 protection and operate from −25 °C to 70 °C up to 6000 m above sea level, with startup at −40 °C confirmed by type testing. The IN+ connection accepts rigid conductors up to 16 mm². NO denotes a potential-free trip-indication contact, while R denotes a reset input for remote re-energization of a channel, controlled by a 7…30 V DC falling edge.
The multi-channel design suits cabinets with many outgoing circuits: wayside power and automation cabinets, interlockings and substation auxiliary circuits. Eight protected channels fit within 41 mm width, and a common signal contact reports their status-reducing the number of diagnostic inputs required in an unattended facility. As in the single-channel family, the tripping characteristic is matched to switched-mode power supplies.
The datasheet lists EN/IEC 61000-6-2, EN/IEC 61000-6-3 and EN/IEC 61000-6-8, environmental tests IEC 60068-2-1 (cold), IEC 60068-2-2 (dry heat), IEC 60068-2-6 (vibration), IEC 60068-2-27 (shock), IEC 60068-2-30 (cyclic damp heat) and IEC 60068-2-78 (steady-state damp heat), as well as ISA S71.04.2013 G3 Harsh Group A corrosion testing and UL/C-UL Listed UL 508, UL Recognized UL 2367, ANSI/ISA-12.12.01 Class I Division 2 Groups A–D and DNV GL approvals. The Phoenix Contact railway catalogue table marks EN 61373 and −40 °C testing for both items, but does not mark EN 45545-2 or EN 50121-3-2. The table does not give an EN 61373 category or class, but the datasheets give direct values: 30g shock according to IEC 60068-2-27 (test Ea) and vibration of 5…24.9 Hz at ±1.6 mm amplitude and 24.9…150 Hz at 4g according to IEC 60068-2-6 (test Fc). The lack of confirmed fire protection excludes installation inside a rail vehicle-there, the single-channel PTCB E1 remains the appropriate choice. CBM is assigned exclusively to infrastructure applications.
