DEHN DSH TNC 255 Type 1+2 Combined Surge Arrester for TN-C Systems, 4-Pole, 255 V AC, 25 kA (10/350 µs) per Pole, 100 kA Total, DIN Rail Mount, Red

Lightning strikes and switching surges can destroy sensitive equipment in TN-C power distribution systems, causing costly downtime and repairs. The DEHN DSH TNC 255 is a combined Type 1+2 surge arrester that protects your installation by safely diverting both high-energy lightning currents and fast transient overvoltages to earth. Its compact 4-pole design is engineered for main distribution boards where space is limited but performance is critical.

Who is it for

This arrester is ideal for electricians, panel builders, and facility managers responsible for industrial, commercial, or residential buildings with TN-C networks. It is particularly suited for main distribution boards, service entrances, and locations where a single device must handle both direct lightning currents and switching surges.

Main features

• Combined Type 1+2 protection according to IEC/EN 61643-11, covering lightning impulse currents (10/350 µs) and switching surges (8/20 µs).
• High discharge capacity: 25 kA (10/350 µs) per pole, total 100 kA, with follow current extinguishing capability up to 50 kA rms.
• Low voltage protection level ≤ 1.5 kV, ensuring connected equipment is not exposed to damaging residual voltages.
• Compact 4-pole design for TN-C systems, mounted on a standard 35 mm DIN rail, saving valuable panel space.
• Visual status indication and remote signaling contact (floating changeover) for easy monitoring and integration into building management systems.
• Robust thermoplastic housing in red, UL 94 V-0.

Specifications

• Arrester type: Combined arrester Type 1 + Type 2
• Network system: TN-C
• Max. continuous operating voltage (Uc): 255 V AC
• Nominal discharge current (In) (8/20 µs): 20 kA
• Impulse current (Iimp) (10/350 µs) per pole: 25 kA
• Total impulse current (Itotal) (10/350 µs): 100 kA
• Voltage protection level (Up): ≤ 1.5 kV
• Follow current extinguishing capability (Ifi): 50 kA rms
• Short-circuit withstand capability (Isccr): 50 kA rms (with max. backup fuse)
• Max. backup fuse: 315 A gG
• Response time (tA): < 100 ns
• Operating temperature range: -40 °C to +80 °C
• Mounting: 35 mm DIN rail
• Degree of protection: IP20
• Number of poles: 4-pole
• Connection type: Screw terminal
• Conductor cross-section (solid/stranded): 2.5 - 50 mm² / 2.5 - 35 mm²
• Housing material: Thermoplastic, red, UL 94 V-0
• Standards compliance: IEC 61643-11 / EN 61643-11
• Energy coordination: Type 1 + Type 2 + Type 3

Tips

For optimal protection, install the DEHN DSH TNC 255 as close as possible to the service entrance of the building. Ensure proper grounding and use the remote signaling contact to monitor the arrester's status in your building management system. Regularly inspect the visual indicator to confirm the device is operational.