DEHNguard DG M TNS 275 FM Type 2 Surge Arrester, 4-Pole, 275 V AC, 40 kA, IP20, DIN Rail

With a maximum discharge current of 40 kA (8/20 µs) and a voltage protection level of ≤1.2 kV, the DEHNguard DG M TNS 275 FM delivers robust surge protection for TN-S power supply systems. This modular Type 2 surge protective device (SPD) is engineered to safeguard electrical installations from transient overvoltages, ensuring operational continuity and equipment longevity.

Overview

The DEHNguard DG M TNS 275 FM is a four-pole surge arrester designed for 230/400 V AC TN-S networks. It features a varistor-based protection circuit with a nominal discharge current of 20 kA and a maximum discharge current of 40 kA. The device offers protection modes L-N and N-PE, covering all necessary paths for comprehensive surge mitigation. Its follow current extinguishing capability and high short-circuit withstand rating of 50 kA rms (with a maximum backup fuse of 125 A gG) ensure reliable performance under fault conditions.

What stands out

• High discharge capacity: 40 kA (8/20 µs) per pole for demanding surge environments.
• Low voltage protection level (≤1.2 kV) to protect sensitive downstream equipment.
• Visual status indicator (green/red) for quick and easy monitoring of arrester condition.
• Compact modular design for 35 mm DIN rail mounting, saving space in distribution boards.
• Thermoplastic housing (UL 94 V-0) in red, offering excellent fire retardancy and durability.
• Wide operating temperature range from -40 °C to +80 °C, suitable for harsh environments.

Technical details

• Type: Type 2 / Class II surge protective device (SPD) according to EN 61643-11 and IEC 61643-11.
• Network system: TN-S (3P+N configuration).
• Nominal voltage (Un): 230/400 V AC.
• Maximum continuous operating voltage (Uc): 275 V AC.
• Nominal discharge current (In): 20 kA (8/20 µs).
• Maximum discharge current (Imax): 40 kA (8/20 µs).
• Voltage protection level (Up): ≤1.2 kV.
• Protection modes: L-N and N-PE.
• Follow current extinguishing capability: Yes.
• Short-circuit withstand capability (Isccr): 50 kA rms with max. backup fuse.
• Maximum backup fuse: 125 A gG.
• Technology: Varistor.
• Mounting: 35 mm DIN rail (EN 60715).
• Enclosure protection rating: IP20.
• Operating temperature range: -40 °C to +80 °C.
• Housing material: Thermoplastic, red, UL 94 V-0.
• Standards compliance: EN 61643-11, IEC 61643-11.

Our verdict

The DEHNguard DG M TNS 275 FM is a high-performance Type 2 surge arrester that combines robust protection with ease of installation. Its 40 kA discharge capacity and low protection level make it an excellent choice for protecting critical electrical infrastructure in commercial and industrial settings. The visual status indicator and modular design add practical value for maintenance and system monitoring.