Circuit breaker Icu=50kA 1P C 20A HMX120

HMX120 Circuit Breaker

Product codes: HMX120, TN‑S

Circuit breaker HMX120 is a high‑breaking‑capacity device designed for stable and safe protection of circuits in industrial and commercial installations. Its construction allows surface‑mounting in distribution cabinets, and the screw terminals accommodate both single‑core and multi‑core cables – without the need for lugs.

Rated current 20 A with a C‑curve characteristic means the breaker tolerates short‑duration inrush currents when starting motors, pumps, or LED lighting with transformers – without nuisance tripping. A short‑circuit rating of 50 kA at 230 V and 400 V indicates it can safely interrupt even extreme faults in high‑power networks, which is crucial in installations with high fault currents.

The upper and lower terminals are aligned – facilitating wiring and mounting in panels with multiple breakers. The specified tightening torque is 3.5–5.0 Nm: too little torque risks loosening; too much can damage the terminal. Note that the maximum conductor cross‑section is 50 mm² for flexible cables and 70 mm² for rigid ones. No lugs are required, but the insulation must be properly inserted into the terminal.

IP20 protection prevents contact with live parts but does not guard against moisture, so the device must not be installed in areas exposed to steam or splashing. It operates over a wide temperature range: ‑25 °C to +70 °C, making it suitable for unheated rooms or outdoor locations under shelter. Energy‑limiting class 3 and surge category 3 mean the breaker supports surge‑protective systems – it is not just a “breaker” but part of an advanced protection network.

DIN‑rail mounting is standard – the unit occupies 1.5 modules (27 mm width). Its height (90 mm) and depth (70 mm) are compatible with most cabinets. It cannot simultaneously disconnect the N pole, so it is unsuitable for TN‑S circuits that require neutral separation. Auxiliary contacts and trip units can be added later, providing flexibility for future upgrades.

The breaker operates at voltages up to 415 V AC and frequencies 50–60 Hz. Insulation voltage (Ui = 500 V) and impulse voltage (6 kV) ensure resistance to transient over‑voltages. Mechanical endurance is 20 000 cycles and electrical endurance 4 000 cycles, suitable for heavily used installations.