Transient Surge Protector PSC4-12.5/400TT 3P+N 12.5kA 4-Module Pluggable

The Cirprotec PSC4-12,5/400 TT, reference 77738405, is a Type 1+2 transient surge protector designed for 3P+N three-phase electrical installations at 230/400 V. Its 3+1 configuration protects the phases with respect to neutral and neutral with respect to earth, providing protection against surges caused by lightning strikes and switching operations on the electrical network.

This protector from the Cirprotec PSC 12.5 range combines the functions of a Type 1 and Type 2 device in a single unit. It supports a lightning impulse current Iimp of 12.5 kA per L-N pole with 10/350 µs waveform and 50 kA between N-PE, together with a nominal discharge current In of 20 kA between L-N. Its pluggable design makes maintenance and cartridge replacement easy without needing to replace the installed base.

Main features of the Cirprotec PSC4-12,5/400 TT

• Type 1+2 transient surge protector according to EN 61643-11.
• Class I+II classification according to IEC 61643-11.
• Manufacturer reference: 77738405.
• Model: PSC4-12,5/400 TT.
• Internal configuration: 3+1.
• 4 poles for 3P+N three-phase installations.
• Rated voltage: 230/400 V AC, 50-60 Hz.
• Maximum continuous operating voltage Uc L-N: 275 V AC.
• Maximum continuous operating voltage Uc N-PE: 255 V AC.
• Lightning impulse current Iimp L-N, 10/350 µs waveform: 12.5 kA.
• Lightning impulse current Iimp N-PE, 10/350 µs waveform: 50 kA.
• Nominal discharge current In L-N, 8/20 µs waveform: 20 kA.
• Nominal discharge current In N-PE, 8/20 µs waveform: 50 kA.
• Maximum discharge current Imax: 65 kA.
• Protection level Up L-N: ≤1.3 kV.
• Protection level Up N-PE: ≤1.5 kV.
• Pluggable design with replaceable cartridges.
• DIN rail mounting.
• Width: 4 DIN modules.
• Compatible with TT and TNS network configurations.
• Protection modes L-N / N-PE.
• Visual status indicator.
• IP20 protection rating.

Type 1+2 protection against transient surges

The PSC4-12,5/400 TT is designed to limit high-energy transient surges that can propagate through an electrical installation. By integrating Type 1+2 protection, it can handle both currents associated with lightning impulses and surges induced or caused by switching operations on the network.

Its impulse current capability reaches 12.5 kA between phase and neutral with 10/350 µs waveform, while between neutral and earth it reaches 50 kA. For 8/20 µs waveform impulses, it offers a nominal discharge current of 20 kA between phase and neutral and a maximum discharge current of 65 kA.

3+1 configuration for three-phase installations

The protector features an internal 3+1 configuration, with three protection elements between the phases and neutral and an additional element between neutral and earth. This architecture is especially suited to three-phase installations with neutral and allows use in TT and TNS network configurations.

The rated operating voltage of model 77738405 is 230 V between phase and neutral and 400 V between phases, with a mains frequency of 50-60 Hz.

Protection level and discharge capacity

Parameter Value EN classification Type 1+2 IEC classification Class I+II Rated voltage Un 230/400 V AC Frequency 50-60 Hz Maximum continuous voltage Uc L-N 275 V AC Maximum continuous voltage Uc N-PE 255 V AC Lightning impulse current Iimp L-N (10/350 µs) 12.5 kA Lightning impulse current Iimp N-PE (10/350 µs) 50 kA Nominal discharge current In L-N (8/20 µs) 20 kA Nominal discharge current In N-PE (8/20 µs) 50 kA Maximum discharge current Imax L-N 65 kA Maximum discharge current Imax N-PE 65 kA Protection level Up L-N ≤1.3 kV Protection level Up N-PE ≤1.5 kV

Safety and electrical performance

The protector incorporates dynamic thermal disconnection and operates in open-circuit mode if the thermal protection is triggered. Its short-circuit withstand capability Isccr is 25 kA and it accepts a maximum backup fuse of 200 A gG, according to Cirprotec specifications.

The response time is up to 25 ns between phase and neutral and up to 100 ns between neutral and earth. This fast operation helps limit the surge voltage reaching downstream connected equipment.

Pluggable design and maintenance

The PSC4-12,5/400 TT features pluggable cartridges, a solution that simplifies maintenance tasks. If one of the modules reaches the end of its service life, the corresponding cartridge can be replaced without fully removing the protector or modifying the base wiring.

The visual signaling system allows quick verification of the device status: the green indicator shows correct operation, while the loss of the green indication signals the need to replace the corresponding cartridge.

Mechanical specifications

Feature Value Number of poles 4 Internal configuration 3+1 Number of DIN modules 4 Format Pluggable Network configuration TT, TNS Protection modes L-N / N-PE Protection rating IP20 Insulating material PA66 CT1 Flammability class UL94 V-0 Rigid conductor cross-section 6 to 35 mm² Flexible conductor cross-section 6 to 25 mm² Tightening torque 3 Nm Temperature range -40 to 85 °C Humidity range 5 to 95 % Approximate dimensions 90 x 72 x 76 mm Net weight 0.618 kg

Installation and applications

The protector is designed for DIN rail mounting and occupies four modules in the electrical panel. The Biconnect connection system in the PSC range allows connection by cable and terminal or by connection comb, making integration into different panel configurations easier.

Thanks to its performance, the Cirprotec PSC4-12,5/400 TT is suitable for protecting three-phase electrical installations in buildings, industry, telecommunications, water treatment, electric vehicle charging infrastructure, and other applications where high-energy transient surges need to be limited.

Standards

The Cirprotec PSC4-12,5/400 TT complies with IEC 61643-11 and EN 61643-11 standards for surge protective devices connected to low-voltage electrical networks.

Thanks to its high discharge capacity, combined Type 1+2 protection, 3P+N three-phase configuration, and pluggable cartridge construction, the Cirprotec PSC4-12,5/400 TT offers a robust and practical solution for protecting electrical installations and equipment against transient surges.