Mersen 44020305 K2-3P320-M Type 2 three-pole surge protection device for 277/480 V TN-C systems, featuring remote signalling, a 320 V AC maximum continuous operating voltage, 20 kA nominal discharge current and 50 kA maximum discharge current.
£131.24
The Mersen 44020305, also identified as the K2-3P320-M, is a high-performance Type 2 surge protection device (SPD) designed to protect three-phase low-voltage electrical installations against transient overvoltages. Part of the trusted Mersen Surge-Trap K2 series, it is suitable for 277/480 V TN-C electrical systems and incorporates an integrated remote signalling contact for continuous condition monitoring.
The K2-3P320-M uses a compact pluggable construction, allowing the protection cartridges to be inspected or replaced without removing the complete DIN-rail base. A clear visual status indicator provides local confirmation of the device condition, while the integrated microswitch enables remote monitoring through PLCs, SCADA platforms, alarm circuits and building management systems.
Featuring a 320 V AC maximum continuous operating voltage, a 20 kA nominal discharge current and a 50 kA maximum discharge current, the Mersen 44020305 provides dependable protection against lightning-induced surges and switching transients. Its three-pole design is ideal for industrial switchgear, commercial distribution boards, motor control centres and automation installations where remote indication is required.
Transient overvoltages produced by indirect lightning strikes, utility switching, motors, transformers and other inductive loads can damage PLCs, variable speed drives, communication equipment and power supplies. Although these voltage spikes are extremely brief, they can cause immediate equipment failure or gradually degrade sensitive electronic components.
The Mersen K2-3P320-M diverts excessive surge energy towards earth before it reaches connected equipment. Its integrated remote contact allows maintenance teams to monitor the protection status from a central control system, while the pluggable cartridges provide fast replacement when servicing becomes necessary.
| Voltage | 480 V |
|---|---|
| Phase | Three Phase |
| Manufacturer | Mersen |
| Series | Surge-Trap K2 |
| Model | K2-3P320-M |
| SKU / Part number | 44020305 |
| 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 |
| Protection mode | L-PE(N) |
| Nominal operating voltage | 277/480 V AC |
| Maximum continuous operating voltage | 320 V AC |
| Nominal discharge current | 20 kA |
| Maximum discharge current | 50 kA |
| Surge current waveform | 8/20 µs |
| Voltage protection level | ≤1.5 kV |
| Response time | ≤25 ns |
| Residual current | <1 mA |
| Short-circuit withstand rating | 25 kA |
| Maximum back-up fuse | 315 A gG |
| Thermal protection behaviour | Open Circuit Mode |
| Dynamic thermal disconnection | Yes |
| Status indication | Green (OK) / Not green (replace) |
| Remote signalling | Integrated microswitch |
| Terminal tightening torque | 3 Nm |
| Construction | Pluggable |
| Mounting type | DIN rail |
| DIN rail modules | 3 |
| Dimensions (H × W × D) | 90 × 54 × 74.4 mm |
| RoHS compliant | Yes |
| EAN / UPC | 8435297889908 |
| HS Code | 85363090 |
| Country of Manufacture | Spain |
The Mersen 44020305 protects three-phase 277/480 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 intended primarily as a second level of protection in low-voltage electrical installations.
Yes. The integrated microswitch can transmit the device status to PLCs, alarm circuits, SCADA platforms and building management systems.
The device has a 20 kA nominal discharge current and a 50 kA maximum discharge current, based on the standard 8/20 µs surge waveform.
The K2-3P320-M is designed for three-phase 277/480 V TN-C electrical systems and has a maximum continuous operating voltage of 320 V AC per protection pole.
Yes. The pluggable construction allows the protection cartridges to be replaced without disconnecting or removing the complete DIN-rail base.
Mersen Surge-Trap K2 surge protection devices are trusted by electrical engineers, panel builders and maintenance professionals to protect critical three-phase installations while providing straightforward servicing and dependable remote condition monitoring.
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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...