Overcurrent circuit breaker Icu=50kA 3P C 20A HMX320

HMX320 overload circuit breaker

The HMX320 overload circuit breaker is a high‑breaking‑capacity device designed for use in industrial and commercial installations where reliable overload and short‑circuit protection is required. Its construction allows safe and rapid disconnection of the circuit at short‑circuit currents up to 50 kA — even at 400 V AC — making it suitable for networks with high loads, such as motor‑driven machines or distribution systems in production halls.

Characteristic C provides delayed tripping for short but high inrush currents — ideal for protecting equipment with motors, transformers or LED lighting with high start‑up current. It does not trip unintentionally on impulses that are normal in the operation of electrical couplings.

Surface‑mount installation on a 35 mm DIN rail is standard and easy — thanks to modern clips, the breaker can be added or removed even within an already installed busbar arrangement. Screw terminals accommodate both single‑core conductors (1–70 mm²) and multi‑core cables (1–50 mm²), providing flexibility when connecting different cable types. The tightening torque of 3.6 Nm is precisely specified — a regular screwdriver with a standard PZ2 tip is sufficient, no torque wrench required.

IP20 protection rating ensures safety against accidental contact with live parts — suitable for installation in distribution cabinets. A height of 90 mm and width of 80 mm (4.5 modules) allow compact mounting in confined spaces. Operation over a wide temperature range — from –25 °C to +70 °C — makes it usable both in unheated rooms and in hot production environments.

Optional accessories (auxiliary contacts, residual‑current devices) enable functional expansion — e.g., status indication or integration with automation systems. Compliance with IEC 60947-2 and energy‑limiting class 3 means the breaker meets the latest safety standards and limits the energy let‑through to the fault location — reducing the risk of installation damage.

Aligned upper and lower terminals simplify busbar connection — no need to trim cable lengths or use additional adapters. A status indicator (green = OFF, red = ON) is visible from the front — no need to open the cabinet to check circuit condition. The absence of simultaneous N‑pole disconnection means this is a three‑pole (3P) breaker without neutral isolation — typical for TN-S or TN-C-S systems.

No special mounting conditions are required: it can be installed vertically, horizontally or even “upside‑down” while retaining full functionality. Mechanical endurance of 20 000 cycles and electrical endurance of 4 000 trips ensure it is suited for frequent use without performance loss.