Mersen STPT12-12K275V-4PG Type 1+2 pluggable surge protection device with 12.5 kA lightning impulse current, 275 V maximum continuous operating voltage, 230/400 V AC nominal voltage, 4 pole 3+1 TT configuration and DIN rail mounting.
£348.24
The Mersen 83120138 STPT12-12K275V-4PG is a high-performance Type 1+2 Surge Protection Device (SPD) designed to protect low voltage electrical installations against transient overvoltages caused by lightning activity and switching events. As part of the Mersen Surge-Trap® Pluggable STPT12 Series, it provides reliable first-stage surge protection for three-phase plus neutral TT power distribution systems.
This pluggable SPD combines Class I and Class II surge protection in a compact DIN rail mounted format. Its 3+1 TT configuration provides coordinated protection between live conductors and neutral, with additional protection between neutral and earth, making it suitable for incoming supply panels and installations exposed to atmospheric surges.
With a 12.5 kA lightning impulse current rating, 230/400 V nominal operating voltage and 275 V maximum continuous operating voltage, the Mersen 83120138 is ideal for protecting main distribution boards, switchboards, control panels and sensitive electrical equipment from damaging voltage surges.
Surge protection devices help protect electrical systems by safely limiting transient overvoltages before they reach connected equipment. This reduces the risk of damage to switchgear, control systems, drives, PLCs, instrumentation, power supplies and other sensitive electrical components.
The Mersen STPT12 range is designed for use as the first level of protection in main distribution boards and incoming supply panels. Its Type 1+2 classification makes it suitable for installations exposed to atmospheric surges and applications requiring coordinated protection against lightning currents and voltage spikes.
| Voltage | 400 V |
|---|---|
| Phase | Three Phase |
| Manufacturer | Mersen |
| Series | Surge-Trap® Pluggable STPT12 |
| Model | STPT12-12K275V-4PG |
| SKU | 83120138 |
| Product type | Type 1+2 Surge Protection Device |
| IEC classification | Class I+II |
| Lightning impulse current (Iimp) | 12.5 kA (10/350 μs) |
| Maximum discharge current (Imax) | 50 kA (8/20 μs) |
| Nominal discharge current (In) | 20 kA (8/20 μs) |
| Nominal operating voltage (Un) | 230/400 V AC |
| Maximum continuous operating voltage (Uc) | 275 V |
| System configuration | 3+1 TT |
| Network type | 3 phase + neutral |
| Protection modes | L-N / N-PE |
| Number of poles | 4 |
| Number of modules | 4 |
| Mounting type | 35 mm DIN rail |
| Protection rating | IP20 |
| Format | Pluggable |
| EAN / UPC code | 8435297851523 |
It is used to protect low voltage electrical installations against transient overvoltages caused by lightning activity and switching events.
The Mersen 83120138 provides combined Type 1+2 / Class I+II surge protection.
It is designed for 3 phase plus neutral, 3+1 TT systems operating at 230/400 V AC.
The device has a 275 V maximum continuous operating voltage, making it suitable for 230/400 V AC systems.
It is typically installed on a DIN rail inside main distribution boards, incoming panels or electrical switchboards.
Mersen Surge-Trap® surge protection devices are trusted by electrical engineers, panel builders and industrial facilities worldwide for dependable protection of power distribution systems and sensitive connected equipment.
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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...