DEHN 941315 DSH TT 255 FM Type 1+2 Surge Arrester for 3-Phase TT/TN-S Systems

Type 1+2 combined surge arrester for 3-phase TT and TN-S systems, offering high discharge capacity and low voltage protection level. The DEHNshield DSH TT 255 FM protects low-voltage consumer installations from surge voltages caused by lightning strikes or switching operations.

Advantages

Combines Type 1 and Type 2 protection in a single device, saving space and installation time. High discharge capacity ensures reliable protection even under severe surge conditions. Remote signalling contact (FM) enables remote monitoring of arrester status. Suitable for both TT and TN-S earthing systems, providing flexibility in various electrical installations.

Suitable for

• Three-phase low-voltage power distribution systems
• TT and TN-S earthing arrangements
• Protection of sensitive electronic equipment
• Industrial, commercial, and residential applications

Key specifications

• Nominal voltage: 230 / 400 V AC
• Max. continuous operating voltage: 255 V AC
• Nominal discharge current (8/20 µs): 20 kA
• Max. discharge current (8/20 µs): 50 kA
• Impulse current (10/350 µs): 7 kA
• Voltage protection level: ≤ 1.5 kV
• Follow current extinguishing capability: 100 A AC
• Response time: ≤ 100 ns
• Operating temperature range: -40 °C to +80 °C
• Mounting: 35 mm DIN rail
• Number of poles: 3+1 (3 phases + N-PE)
• Remote signalling contact: Yes
• Standards compliance: IEC 61643-11 / EN 61643-11
• Short-circuit withstand capability: 25 kA
• Max. backup fuse: 160 A gG

Recommendations

Install at the main distribution board to protect the entire installation. Ensure proper earthing and follow local regulations. Use the remote signalling contact to integrate with building management systems for proactive maintenance.