Circuit breaker Icu=50kA 3P C 16A HMX316

Overcurrent and short‑circuit protection in three‑phase installations

Circuit breaker HMX316 provides effective protection for 415 V AC three‑phase circuits, especially where high inrush currents occur — e.g., with motors, pumps or compressors. The C‑characteristic allows it to withstand short‑duration current flows during the start‑up of mechanical couplings without false tripping, increasing system reliability.

Short‑circuit rating 50 kA at 230 V and 400 V means the device will safely open the circuit even in the case of an extremely high fault — crucial in modern industrial and commercial installations where fault currents can be high. Energy‑limiting class 3 and surge category 3 further enhance safety by limiting the amount of energy transferred to the circuit during a fault.

Installation and operating conditions

Surface‑mounted (DIN‑rail) installation is standard — no additional mounting hardware required. A width of 4.5 modules allows compact placement in distribution boards, and an embedding depth of 70 mm makes it fit most enclosures. Terminals are screw‑type and arranged in parallel — facilitating the installer’s work when connecting both single‑core cables (up to 70 mm²) and multi‑core cables (up to 50 mm²). Tightening torque is 3.6 Nm — a regular screwdriver with a torque limiter is sufficient.

Operating temperature from –25 °C to +70 °C permits use in various environments — from refrigerated warehouses to rooms with high internal temperatures. IP20 protection rating guards against contact with live parts, but it is not intended for outdoor or humid locations.

Compliance and functionality

Compliant with IEC 60947‑2 and EN 60898‑1 — meets requirements for tertiary installations (office, commercial). It does not have a separately disconnectable neutral pole — therefore it is unsuitable for circuits requiring neutral isolation. Optional accessories (e.g., mechanical locks, terminal covers) allow adaptation of the device to specific safety or access‑control needs.

Note: although the breaker has a high short‑circuit rating, its effectiveness depends on proper conductor selection and correct installation — it does not replace other protective devices.