Mersen 44020404 K2-4P275 Type 2 surge protection device for 230/400 V AC TNS systems with a 4+0 configuration, 20 kA nominal discharge current and 50 kA maximum discharge current.
£135.62
The Mersen 44020404, also known as the K2-4P275, is a robust Type 2 surge protection device (SPD) designed to protect low-voltage electrical installations against transient overvoltages caused by indirect lightning strikes and switching events. As part of the Mersen Surge-Trap® K2 Series, this pluggable four-pole SPD provides reliable protection for 230/400 V AC TNS electrical systems.
Featuring a 4+0 protection configuration, the K2-4P275 protects all live conductors individually, making it particularly suitable for TNS earthing systems. With a 20 kA nominal discharge current and a 50 kA maximum discharge current, it safeguards sensitive electrical equipment including control panels, switchboards, automation systems and industrial machinery.
Its reinforced pluggable design allows rapid replacement of protection cartridges without removing the DIN rail base. A built-in visual status indicator provides immediate confirmation of operational status, helping minimise maintenance time while ensuring continuous surge protection.
Electrical equipment is vulnerable to damaging voltage transients generated by lightning activity, switching operations and utility disturbances. The Mersen K2-4P275 safely diverts these surge currents away from connected equipment, helping reduce costly downtime and extending the service life of electrical assets.
Its 4+0 architecture provides dedicated protection for each live conductor within TNS systems, making it an excellent choice for industrial switchboards, commercial distribution panels and critical electrical infrastructure where dependable surge protection is essential.
| Voltage | 400 V |
|---|---|
| Phase | Three Phase |
| Manufacturer | Mersen |
| Series | Surge-Trap® K2 Series |
| Model | K2-4P275 |
| Manufacturer part number | 44020404 |
| Product type | Type 2 surge protection device |
| Configuration | 4+0 |
| IEC SPD classification | Type 2 / Class II |
| UL SPD classification | Type 1 Component Assembly |
| Nominal operating voltage | 230/400 V AC |
| Maximum continuous operating voltage (Uc) | 275 V AC |
| Nominal discharge current (In) | 20 kA |
| Maximum discharge current (Imax) | 50 kA |
| Voltage protection level (Up) | ≤1.5 kV |
| System configuration | TNS |
| Number of poles | 4 |
| Short-circuit current rating | 25 kA |
| Maximum back-up fuse | 315 A gG |
| Protection rating | IP20 |
| Mounting type | DIN rail |
| Connection torque | 3 N·m |
| Solid conductor capacity | 1.5 to 35 mm² |
| Stranded conductor capacity | 1.5 to 25 mm² |
| Operating temperature | -40 to +85 °C |
| Maximum installation altitude | 4,000 m |
| Housing material | PA6 CT1 & PA66 CT1 |
| Flammability rating | UL94 V-0 |
| Dimensions (H × W × D) | 90 × 72 × 74.4 mm |
| Weight | approx. 0.435 kg |
| RoHS compliant | Yes |
| HS Code | 85363090 |
| Country of Manufacture | Spain |
The Mersen 44020404 is a Type 2 surge protection device that protects three-phase TNS electrical installations from transient overvoltages caused by lightning and switching events.
The K2-4P275 uses a 4+0 configuration for TNS systems, while the K2-4PG275 features a 3+1 configuration designed primarily for TT and TNS networks.
The device has a nominal discharge current of 20 kA and a maximum discharge current of 50 kA per phase.
Yes. The surge protection cartridges are fully pluggable, allowing individual modules to be replaced without removing the complete base from the DIN rail.
The device is commonly installed in electrical distribution boards, industrial control panels and commercial switchboards operating on 230/400 V AC TNS systems.
Mersen Surge-Trap® K2 Series surge protection devices help improve electrical system reliability by protecting valuable equipment against damaging transient overvoltages in commercial, industrial and infrastructure installations.
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2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...