Mersen 44020309 K2-3P440-M Type 2 three-pole surge protection device with integrated remote signalling for 400/690 V TN-C systems, featuring a 440 V AC maximum continuous operating voltage, 20 kA nominal discharge current and 50 kA maximum discharge current.
£131.24
The Mersen 44020309, also identified as the K2-3P440-M, is a premium Type 2 surge protection device (SPD) engineered to protect three-phase low-voltage electrical installations against transient overvoltages. Part of the trusted Mersen Surge-Trap K2 series, it is designed for 400/690 V TN-C electrical systems and is also suitable for 400 V IT network configurations. An integrated remote signalling contact enables continuous monitoring of the protection status from a central control system.
Its pluggable construction allows the protection cartridges to be replaced quickly without removing the complete DIN-rail base, reducing maintenance time and minimising downtime. A visual status indicator provides immediate local confirmation of the device condition, while the built-in microswitch transmits the operational status to PLCs, SCADA systems or building management systems.
With a 440 V AC maximum continuous operating voltage, 20 kA nominal discharge current and 50 kA maximum discharge current, the Mersen K2-3P440-M provides dependable protection against lightning-induced surges and switching transients in demanding commercial and industrial installations.
Transient overvoltages generated by indirect lightning strikes, utility switching operations, motors, transformers and other inductive loads can damage PLCs, drives, communication equipment, power supplies and sensitive control electronics. A dedicated Type 2 SPD helps prevent costly equipment failures, minimise downtime and improve long-term electrical reliability.
The Mersen K2-3P440-M combines high surge current capability with integrated remote signalling, allowing maintenance personnel to monitor protection status remotely while benefiting from fast replacement of the plug-in protection cartridges whenever servicing is required.
| Voltage | 690 V |
|---|---|
| Phase | Three Phase |
| Manufacturer | Mersen |
| Series | Surge-Trap K2 |
| Model | K2-3P440-M |
| SKU / Part number | 44020309 |
| Product type | Surge protection device |
| IEC SPD classification | Type 2 / Class II |
| UL SPD classification | Type 1 Component Assembly |
| Configuration | 3+0 |
| Number of poles | 3 |
| System configuration | TN-C (also suitable for 400 V IT networks) |
| Protection mode | L-PE(N) |
| Nominal operating voltage | 400/690 V AC |
| Maximum continuous operating voltage | 440 V AC |
| Nominal discharge current | 20 kA |
| Maximum discharge current | 50 kA |
| Voltage protection level | ≤2.0 kV |
| Response time | ≤25 ns |
| Residual current | <1 mA |
| Short-circuit withstand rating | 25 kA |
| Maximum back-up fuse | 315 A gG |
| Dynamic thermal disconnection | Yes |
| Thermal protection behaviour | Open Circuit Mode (OCM) |
| Status indication | Green (OK) / Not green (replace) |
| Remote signalling | Integrated microswitch |
| Terminal tightening torque | 3 Nm |
| Housing material | PA6 CT1 & PA66 CT1 |
| Mounting type | DIN rail |
| DIN rail modules | 3 |
| Replacement cartridge | Cartridge ID C34 |
| Weight | approx. 0.405 kg |
| EAN | 8435297889922 |
| RoHS compliant | Yes |
| HS Code | 85363090 |
| Country of Manufacture | Spain |
The Mersen 44020309 protects three-phase 400/690 V electrical installations against transient overvoltages while providing remote indication of the surge protection device status.
It is a Type 2 / Class II surge protection device designed as a secondary level of protection for low-voltage electrical installations.
Yes. An integrated microswitch provides remote status indication to PLCs, SCADA systems, alarm circuits and building management systems.
The K2-3P440-M is designed for 400/690 V TN-C systems and is also suitable for 400 V IT network configurations.
The device is rated for a 20 kA nominal discharge current and a 50 kA maximum discharge current using the standard 8/20 µs surge waveform.
Yes. The pluggable construction allows the protection cartridges to be replaced without removing the complete DIN-rail base, reducing servicing time.
Mersen Surge-Trap K2 surge protection devices are trusted by electrical engineers, panel builders and maintenance professionals to protect critical three-phase electrical systems while providing dependable remote monitoring and simplified maintenance.
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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...