DEHN 943405 DG MD TNS 275 FM Type 2 Surge Arrester 3+1 Poles 40kA

Engineered to clamp voltage spikes down to ≤1.2 kV, the DEHN 943405 DG MD TNS 275 FM delivers a 40 kA maximum discharge capacity for robust Type 2 surge protection in TN-S networks. This 3+1 pole arrester combines high-energy varistor technology with pluggable modules and a remote signaling contact (FM) for reliable status monitoring.

Overview

The DEHN 943405 is a Type 2 / Class II surge protective device (SPD) designed for 230/400 V AC TN-S power systems. It features a nominal discharge current of 20 kA (8/20 µs) and a maximum discharge current of 40 kA, ensuring effective protection against transient overvoltages. The unit operates with a maximum continuous voltage of 275 V AC and offers a voltage protection level of ≤1.2 kV, safeguarding sensitive equipment from damage.

What stands out

• High discharge capacity: 40 kA (8/20 µs) for demanding surge environments.
• Pluggable protection modules for quick replacement without disconnecting wiring.
• Remote signaling contact (FM) enables remote monitoring of device status.
• Compact 3+1 pole design for TN-S systems, saving space on 35 mm DIN rail.
• Follow current extinguishing capability of 100 A rms enhances operational safety.
• Short-circuit withstand rating of 25 kA rms ensures resilience under fault conditions.
• Wide operating temperature range from -40 °C to +80 °C for harsh environments.
• Thermoplastic housing with UL 94 V-0 flammability rating for fire safety.

Technical details

• SPD type: Type 2 / Class II
• Network system: TN-S
• Nominal voltage (U_N): 230/400 V AC
• Max. continuous operating voltage (U_C): 275 V AC
• Nominal discharge current (I_n) (8/20 µs): 20 kA
• Max. discharge current (I_max) (8/20 µs): 40 kA
• Voltage protection level (U_p): ≤1.2 kV
• Follow current extinguishing capability (I_fi): 100 A rms
• Short-circuit withstand capability (I_SCCR): 25 kA rms
• Response time (t_A): ≤100 ns
• Operating temperature range: -40 °C to +80 °C
• Mounting type: 35 mm DIN rail
• Number of poles: 3+1
• Degree of protection: IP20
• Remote signaling contact: Yes (FM)
• Standards: EN 61643-11, IEC 61643-11
• Protection technology: Varistor-based, pluggable modules
• Housing material: Thermoplastic, UL 94 V-0

Our verdict

The DEHN 943405 is a high-performance surge arrester that combines robust protection with convenient maintenance features. Its pluggable design and remote signaling make it an excellent choice for critical TN-S installations where uptime and safety are paramount.