Complementary
Network frequency	50/60 Hz
[Ue] rated operational voltage	380...415 V AC 50/60 Hz; 500 V AC 50/60 Hz; 220...240 V AC 50/60 Hz; 440 V AC 50/60 Hz;
Magnetic tripping limit	8 x In
[Ics] rated service breaking capacity	37.5 kA 75 % conforming to EN/IEC 60947-2 - 220...240 V AC 50/60 Hz; 18.75 kA 75 % conforming to EN/IEC 60947-2 - 380...415 V AC 50/60 Hz; 15 kA 75 % conforming to EN/IEC 60947-2 - 440 V AC 50/60 Hz; 7.5 kA 75 % conforming to EN/IEC 60947-2 - 500 V AC 50/60 Hz; 25 kA 100 % conforming to EN/IEC 60947-2 - 250 V DC
[Ui] rated insulation voltage	690 V AC 50/60 Hz conforming to EN/IEC 60947-2
[Uimp] rated impulse withstand voltage	8 kV conforming to EN/IEC 60947-2
Control type	Toggle; Manual tripping test
Local signalling	ON/OFF indication; Trip indicator
Mounting mode	Clip-on
Mounting position	Vertical
Mounting support	35 mm symmetrical DIN rail
9 mm pitches	6
Height	103 mm
Depth	81 mm
Width	54 mm
Net weight	0.48 kg
Mechanical durability	20000 cycles
Electrical durability	5000 cycles
Provision for padlocking	Padlockable
Locking options description	Integrated padlocking
Connections - terminals	Tunnel type terminals16…70 mm² rigid; Tunnel type terminals10…50 mm² flexible
Wire stripping length	20 mm
Tightening torque	6 N.m
Earth-leakage protection	Separate block
Contact position indicator
Comb busbar and distribution block compatibility
Contractual warranty
Warranty (in months)	18
Environment
IP degree of protection	IP20 conforming to IEC 60529
IK degree of protection	IK05 conforming to EN/IEC 62262
Pollution degree	3 conforming to IEC 60947-2
Overvoltage category	IV
Tropicalisation	2 conforming to IEC 60068-1
Relative humidity	95 % at 55 °C
Ambient air temperature for operation	-30…70 °C
Ambient air temperature for storage	-40…70 °C
Main
Range	Acti9
Product name	Acti9 NG125
Product or component type	Miniature circuit-breaker
Device short name	NG125N
Device application	Distribution
Poles description	2P
Number of protected poles	2
[In] rated current	80 A at 40 °C
Network type	AC; DC
Trip unit technology	Thermal-magnetic
Curve code	C
Breaking capacity	10 kA Icu at 500 V AC 50/60 Hz conforming to EN/IEC 60947-2; 20 kA Icu at 440 V AC 50/60 Hz conforming to EN/IEC 60947-2; 25 kA Icu at 380...415 V AC 50/60 Hz conforming to EN/IEC 60947-2; 50 kA Icu at 220...240 V AC 50/60 Hz conforming to EN/IEC 60947-2; 20 kA Icu at
Utilisation category	Category A conforming to IEC 60947-2
Suitability for isolation	Yes conforming to IEC 60947-2
Standards	EN/IEC 60947-2
Packing Units
Unit Type of Package 1	PCE
Number of Units in Package 1	1
Package 1 Height	5.8 cm
Package 1 Width	8 cm
Package 1 Length	11 cm
Package 1 Weight	499 g
Unit Type of Package 2	BB1
Number of Units in Package 2	6
Package 2 Height	9 cm
Package 2 Width	12 cm
Package 2 Length	36 cm
Package 2 Weight	3.079 kg
Unit Type of Package 3	S03
Number of Units in Package 3	36
Package 3 Height	30 cm
Package 3 Width	30 cm
Package 3 Length	40 cm
Package 3 Weight	19.016 kg

The Acti9 NG125N circuit breaker from Schneider Electric is a two-pole (2P) line protection switch designed for use in distribution systems. It is rated for a nominal current of 80 A at an ambient temperature of 40 °C and features a C-characteristic, indicating a thermal-magnetic tripping technology. This technology ensures protection of the circuit against both overload currents and short-circuit currents. Tripping is indicated by the central position of the operating handle and a red mechanical indicator on the front of the device. An integrated test button allows for manual verification of the tripping mechanism to ensure functionality.

Applications

The NG125N is designed for use in industrial and commercial electrical installations, particularly in distribution switchgear. It is suitable for applications requiring reliable circuit protection, such as machine controls, lighting systems, or drive systems. The operating voltage covers multiple ranges: 220–240 V AC, 380–415 V AC, 440 V AC, and 500 V AC, each at 50/60 Hz. The rated insulation voltage is 690 V AC, ensuring high electrical strength. The protection rating IP20 and IK05 safeguard against mechanical impacts and foreign objects, with the devices intended for use in enclosed switch cabinets.

Functions and Equipment in Detail

The switch features a contact position indicator that visually displays the ON/OFF status. Additionally, an integrated tripping indicator allows recognition of the tripping event. Mounting is done on a 35 mm symmetrical DIN rail, with devices required to be mounted vertically. Connections are made via tunnel terminals, designed for fixed conductors with cross-sections from 16 to 70 mm² and flexible conductors from 10 to 50 mm². The wire stripping length is 20 mm, and the required tightening torque for the terminals is 6 Nm. The mechanical life expectancy is 20,000 switching cycles, while the electrical life expectancy is 5,000 cycles.

Technology Explained Simply

The thermal-magnetic tripping technology combines a thermal and a magnetic tripping element. The thermal part responds to sustained overloads by activating the tripping mechanism through thermal expansion. The magnetic part reacts to sudden, high short-circuit currents and trips immediately. The C-characteristic means that tripping occurs at 5 to 10 times the nominal current (In), with the magnetic tripping threshold set at 8 x In here. The breaking capacity reaches up to 50 kA Icu at 220–240 V AC, ensuring high safety during short-circuit events. The rated service breaking capacity (Ics) ranges from 7.5 kA to 37.5 kA depending on the voltage range.

Compatibility and Accessories

The NG125N is part of the Acti9 series and can be combined with various optional auxiliary modules. These include overload release units (e.g. 19064, 19066), undervoltage release units (e.g. 19061, 19067), auxiliary switches (e.g. 19071, 19072), and connection terminals (e.g. 19091, 19095, 19094). These modules extend functionality, for example by adding signaling, remote control, or protection features. The devices are not compatible with comb rails or distribution blocks. The integrated locking feature allows secure securing of the switch with padlocks.

Mounting and Installation

Mounting is done on a 35 mm DIN rail, with devices required to be arranged vertically. Power supply can be from the top or bottom. Dimensions are 54 mm width, 103 mm height, and 81 mm depth. The product weight is 0.48 kg. The operating ambient temperature ranges from -30 °C to +70 °C, and storage temperature from -40 °C to +70 °C. Relative humidity may reach up to 95 % at 55 °C. The overvoltage category IV and pollution degree 3 comply with the requirements of standard IEC 60947-2.

Operational Advantages

The NG125N offers high reliability through thermal-magnetic tripping technology and robust construction. The integrated contact position and tripping indicators simplify maintenance and diagnostics. The ability to connect additional modules extends functionality without additional installation effort. The snap-action switching ensures wear-free switching of contacts, increasing lifespan. The locking option supports safety during maintenance work. Compliance with EN/IEC 60947-2 and VDE certification of the series guarantee adherence to international standards.