MCB S 304 4P B 63A 6000A TX3 403423

Four-pole protection for three-phase installations

The S 304 TX³ circuit breaker is a four-pole thermal-magnetic circuit breaker designed to protect electrical installations from the effects of overloads and short circuits. In the B characteristic variant, the device trips at a rated current of 3-5× In, making it an ideal solution for protecting circuits with low inrush currents - e.g., lighting lines, socket circuits, or electronic devices.

The design includes all four protected poles and a common neutral busbar, which can be disconnected simultaneously with the others. The device is mounted on a TH35 rail (DIN) and occupies 4 modules in width. The installation depth is only 44 mm, which facilitates installation even in shallow flush-mounted distribution boards.

Operating parameters and breaking capacity

The rated short-circuit capacity is 6 kA at 400 V AC according to the EN 60898-1 standard, and at a lower operating voltage (230 V) it reaches 10 kA. The device operates at a frequency of 50-60 Hz and withstands an insulation voltage of up to 500 V, with an impulse voltage level of 4 kV. The energy limiting class is class 3 - the circuit breaker effectively dampens the short-circuit energy, reducing the load on other elements of the installation.

Power can be supplied from both the top and the bottom - this flexibility simplifies wiring in the distribution board. Mechanical durability reaches 20,000 operations, and electrical durability is 4,000 operations, which translates to long-term, trouble-free operation.

Compatibility and expansion

The TX³ series offers a wide range of side-mounted accessories - including auxiliary and signaling contacts, undervoltage and shunt trips, as well as remote actuators. This allows the circuit breaker to be easily expanded with diagnostic functions or integration with building automation systems. Terminal covers and the bottom latch make wiring simple and convenient even with dense module packing in the distribution board.

The grey housing (RAL 7035) is halogen-free, meeting the requirements of standards regarding the reduction of toxic combustible gases in case of fire.

Standard and operating conditions

The device meets the requirements of IEC/EN 60898-1 and holds the VDE certificate. The enclosure protection rating is IP20, IK02 - sufficient for standard distribution boards installed inside buildings. The storage temperature range is from −40°C to +70°C, allowing for storage in various conditions without the risk of component degradation.

When designing a three-phase installation, it is worth remembering that the B characteristic works best where there are no strong inrush currents - unlike the C characteristic (used for inductive loads) or D (for motors and transformers). Choosing the appropriate characteristic affects the selectivity of the entire protection system.