MCB S 301 1P C 50A 6000A TX3 403439

Circuit protection with moderate inrush current

The TX³ series single-pole miniature circuit breaker with C characteristic and a rated current of 50 A is a fundamental protection element in electrical installations for residential, commercial, and industrial buildings. It features a breaking capacity of 6 kA in accordance with the EN 60898 standard, allowing for effective circuit interruption in the event of short circuits and overloads.

The C time-current characteristic means that the electromagnetic trip occurs in the range of 5-10× rated current. In practice, this is ideal for circuits supplying devices with electric motors—such as pumps, compressors, fans, or electric heaters—where momentary current spikes occur during startup, but are not as high as with characteristic D (10-20×). This ensures the breaker does not react falsely to normal equipment startup processes while simultaneously protecting the installation from actual faults.

Construction and dimensions

The device occupies one module on a TH35/DIN rail with a width of 17.8 mm, a height of 88 mm, and a mounting depth of 44 mm (total housing depth is 77.8 mm). The housing is RAL 7035 gray and is made of halogen-free materials—important in the context of fire safety and environmental requirements.

The housing provides an IP20 protection rating, protecting against finger contact and solid foreign objects >12.5 mm. For indoor use—where higher resistance to moisture and dust is required—distribution boards or enclosures that increase the IP class should be used.

Screw terminals accept both single-core and stranded wires, as well as busbars (peigne). Terminal covers and the bottom mounting clip facilitate installation—wires can be conveniently introduced from either the bottom or the top. There is space for a descriptive label on the housing.

Electrical operating parameters

The operating voltage is 230 V AC, with the device tolerating a range up to 415 V AC. An insulation voltage set at 500 V and an impulse voltage of approximately 4 kV allow for safe operation even during momentary network surges. The operating frequency is standardly between 50 and 60 Hz.

The energy limitation class reaches the highest third level—according to the EN 60898 standard, this means the fastest electric arc quenching during disconnection and minimal thermal load on the network. The pollution degree of the working environment is rated as second, defining the permissible atmospheric conditions for the proper functioning of the device.

Mechanical durability reaches up to 20,000 on-off operations, while electrical durability under resistive load reaches 4,000 full switching cycles. The minimum supply voltage for the tripping coil is only 12 V AC—allowing the breaker to work even with simple low-voltage control systems.

Expansion and accessories

The TX³ series offers a wide ecosystem of side-mounted accessories:

• auxiliary contacts (1Z/1R) signaling the on or off state,
• signaling contacts informing of a fault,
• undervoltage releases—automatically disconnecting the circuit when voltage drops below a threshold,
• overvoltage releases—operating upon voltage increases,
• remote drives enabling switching and resetting without the need for physical access to the distribution board,
• mechanical lever locks and padlocks for sealing to prevent tampering by unauthorized persons.

Because of this, a single S301 breaker can become part of an advanced distribution board management system without the need to replace the basic device.

The manufacturer is Legrand Polska Sp. z o.o., with a production plant in Ząbkowice Śląskie specializing in low-voltage protective equipment.