Mersen 44020409 K2-4PG320-M Type 2 surge protection device for 277/480 V AC TT and TNS systems with 50 kA surge capacity and integrated remote indication.
£173.09
The Mersen 44020409, also known as the K2-4PG320-M, is a premium Type 2 surge protection device (SPD) designed to safeguard low-voltage electrical installations from transient overvoltages caused by indirect lightning strikes and switching events. Part of the Mersen Surge-Trap® K2 Series, this pluggable four-pole SPD combines high surge capacity with integrated remote status indication, making it ideal for industrial, commercial and critical infrastructure applications.
Designed for 277/480 V AC three-phase networks, the K2-4PG320-M features a 3+1 protection configuration with L-N and N-PE protection modes for TT and TNS earthing systems. With a 20 kA nominal discharge current and 50 kA maximum discharge current, it provides reliable protection for control panels, automation systems, motor control centres and other sensitive electrical equipment.
Its reinforced pluggable design enables rapid replacement of surge modules without removing the DIN rail base, while the integrated microswitch allows remote monitoring through building management systems, PLCs or alarm circuits. This reduces maintenance time and helps ensure continuous protection of critical installations.
Electrical installations are frequently exposed to damaging voltage transients created by lightning activity, switching operations and utility disturbances. The Mersen 44020409 safely diverts these transient currents away from connected equipment, helping minimise downtime, maintenance costs and premature equipment failure.
Its integrated remote indication contact allows maintenance teams to monitor surge protection status remotely via PLCs, SCADA systems or building management platforms, enabling preventative maintenance and improved operational reliability.
| Voltage | 480 V |
|---|---|
| Phase | Three Phase |
| Manufacturer | Mersen |
| Series | Surge-Trap® K2 Series |
| Model | K2-4PG320-M |
| Manufacturer part number | 44020409 |
| EAN | 8435297887676 |
| Product type | Type 2 surge protection device |
| Configuration | 3+1 |
| IEC SPD classification | Class II / Type 2 |
| UL SPD classification | Type 1 Component Assembly |
| Nominal operating voltage | 277/480 V AC |
| Maximum continuous operating voltage (L-N) | 320 V AC |
| Maximum continuous operating voltage (N-PE) | 255 V AC |
| Nominal discharge current (In) | 20 kA |
| Maximum discharge current (Imax) | 50 kA |
| Voltage protection level (L-N) | ≤1.5 kV |
| Voltage protection level (N-PE) | ≤1.5 kV |
| Voltage protection level (L-PE) | ≤1.8 kV |
| Protection modes | L-N / N-PE |
| System configuration | TT / TNS |
| Number of poles | 4 |
| Short-circuit current rating | 100 kA |
| Following current | 100 A |
| Maximum back-up fuse | 315 A gG |
| Remote indication | Microswitch |
| Remote contact rating | 250 V AC / 0.5 A, 30 V DC / 1 A |
| Protection rating | IP20 |
| Mounting type | DIN rail |
| Connection torque | 3 N·m |
| 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. 0.442 kg |
| RoHS compliant | Yes |
| HS Code | 85363090 |
| Country of Manufacture | Spain |
The Mersen 44020409 is a Type 2 surge protection device designed to protect three-phase electrical systems from transient overvoltages caused by lightning and switching events.
The K2-4PG320-M includes an integrated remote indication microswitch, allowing the operational status of the surge protector to be monitored remotely.
The device is designed for 277/480 V AC TT and TNS systems using a four-pole 3+1 protection configuration.
Yes. The pluggable protection cartridges can be replaced individually without removing the complete DIN rail base.
The unit incorporates both a green visual status indicator and a remote microswitch contact for continuous local and remote condition monitoring.
Mersen Surge-Trap® K2 Series surge protection devices are trusted worldwide to provide reliable protection against transient overvoltages while supporting the long-term reliability of industrial, commercial and infrastructure electrical systems.
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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...