DEHN DSH ZP B2 LSG TT 255 Type 1+2 Combined Surge Arrester 4-Pole 255V 909731

Protect your low-voltage power supply from lightning strikes and surges with the DEHN DSH ZP B2 LSG TT 255. This combined Type 1+2 surge protective device (SPD) is engineered for TT and TN-S systems, offering robust protection for residential, commercial, and industrial installations. It safely discharges high-energy lightning currents and limits transient overvoltages, preventing damage to sensitive equipment and reducing downtime.

Who is it for

This surge arrester is ideal for electricians, panel builders, and facility managers who need reliable protection at the service entrance or main distribution board. It is suitable for installations requiring both lightning current and surge voltage protection, especially in TT earthing systems where the N-PE path demands high discharge capacity.

Main features

• Combined Type 1+2 SPD per IEC/EN 61643-11
• 4-pole configuration (3L+N) for three-phase systems
• High lightning impulse current: 25 kA (10/350 µs) N-PE, 7 kA L-N
• Nominal discharge current 20 kA (8/20 µs) per path
• Voltage protection level ≤ 1.5 kV
• Follow current extinguishing capability 50 kA rms
• Short-circuit withstand 50 kA rms with max. backup fuse
• Fast response ≤ 100 ns
• Wide operating temperature range: -40 °C to +80 °C
• Mounts on 35 mm DIN rail
• IP20 degree of protection
• No integrated backup fuse; external fuse required

Specifications

• SPD type: Type 1 + Type 2
• System configuration: TT and TN-S
• Nominal voltage AC (U_N): 230/400 V (50/60 Hz)
• Max. continuous operating voltage AC (U_C): 255 V
• Lightning impulse current (I_imp) L-N: 7 kA (10/350 µs)
• Lightning impulse current (I_imp) N-PE: 25 kA (10/350 µs)
• Nominal discharge current (I_n) L-N: 20 kA (8/20 µs)
• Nominal discharge current (I_n) N-PE: 20 kA (8/20 µs)
• Voltage protection level (U_p) L-N: ≤ 1.5 kV
• Voltage protection level (U_p) N-PE: ≤ 1.5 kV
• Follow current extinguishing capability (I_fi): 50 kA rms
• Short-circuit withstand capability (I_sccr): 50 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: 4-pole (3+1)
• Degree of protection: IP20
• Standards compliance: IEC 61643-11 / EN 61643-11
• Integrated backup fuse: No (external required)

Tips

Install the DSH ZP B2 LSG TT 255 as close as possible to the incoming supply to minimize let-through energy. Ensure proper earthing and use an external backup fuse as recommended by DEHN. For optimal performance, coordinate with downstream Type 2 or Type 3 SPDs in cascaded protection schemes.