Lightning Current Arrester

Encapsulated creepage discharge spark gap without venting means RADAX Flow spark gap technology with high follow current limitation Energy coordination with other arresters of the Red/Line product family Can also be used upstream of meter panels due to its high insulation resistance Multifunctional terminal for connecting conductors and busbars Single-pole and three-pole version (lightning impulse currents up to 100 kA depending on the system configuration) Modular single-pole version also available


DEHNbloc H M 1 255: Modular single-pole lightning current arrester with high follow current limitation

DEHNbloc 1 255 H: Single-pole lightning current arrester with high follow current limitation

DEHNbloc 3 255 H: Three-pole lightning current arrester with high follow current limitation


The spark gaps of the DEHNbloc lightning current arresters allow a compact configuration of low-voltage distribution boards. By using pressurised and encapsulated creepage discharge spark gaps, no safety distance from busbars and special flameproof enclosures are necessary.

With a lightning current discharge capacity up to 50 kA (10/350 µs) per pole, DEHNbloc devices fulfil the most stringent requirements of national and international lightning protection and application standards.

The consistent improvement of the integration concept made the DEHNbloc devices even more efficient: With DEHNbloc H, the groundbreaking RADAX Flow spark gap technology for follow current extinction and limitation was integrated into the DEHNbloc family.

The RADAX Flow technology prevents that system operation is disrupted due to a tripped line protection as soon as the arrester operates. In times where systems increasingly depend on a properly functioning electrical infrastructure, this is an indispensable product feature. Thanks to the patented RADAX Flow principle, even the amplitude of short-circuit currents in installations up to 50 kArms can be limited to approx. 500 A and extinguished after approximately 5 ms. This feature ensures selectivity even in case of low-value fuses.

But the DEHNbloc H family concept also stands out due to other product features: With its double terminals on the phase and earth side, the single-pole DEHNbloc 1 255 H device offers various application options.

The DBH M 1 255 device with a new arrester design features the approved module release system that safely fixes the protection module to the base part even at maximum loads on the protection module. The modules can be easily replaced without tools by simply pressing the user-friendly module release button of the protection module.

The devices incorporate double terminals suitable for all conductors, allowing series connection of even three-pole DEHNbloc 3 255 H arresters in a space-saving and cost-effective way according to IEC 60364-5-53 requirements for nominal currents up to 125 A.

If DEHNbloc is to be used with other DIN rail mounted devices, multifunctional terminals are ideally suited for providing connection for conductors and busbars.


Type DBH M 1 255
Part No. 961 122
SPD according to EN 61643-11 type 1
SPD according to IEC 61643-1/-11 class I
Nominal a.c. voltage (UN) 230 V
Max. continuous operating a.c. voltage (UC) 255 V
Lightning impulse current (10/350 µs) (Iimp) 50 kA
Voltage protection level (UP) ≤ 4 kV
Follow current extinguishing capability a.c. (Ifi) 50 kArms
Follow current limitation / Selectivity no tripping of a 32 A gL/gG fuse up to 50 kArms (prosp.)
Response time (tA) ≤ 100 ns
Max. backup fuse (L) up to IK = 50 kArms (ta ≤ 0.2 s) 500 A gL/gG
Max. backup fuse (L) up to IK = 50 kArms (ta ≤ 5 s) 315 A gL/gG
Max. backup fuse (L-L') 125 A gL/gG
Temporary overvoltage (TOV) (UT) 440 V / 5 sec.
TOV characteristic withstand
Operating temperature range (parallel connection) (TUP) -40 °C ... +80 °C
Operating temperature range (series connection) (TUS) -40 °C ... +60 °C
Number of ports 1
Cross-sectional area (L/N, L'/N', N/PE(N)) (min.) 10 mm2 solid / flexible
Cross-sectional area (L/N, N/PE(N)) (max.) 50 mm2 stranded / 35 mm2 flexible
Cross-sectional area (L'/N') (max.) 35 mm2 stranded / 25 mm2 flexible
For mounting on 35 mm DIN rails acc. to EN 60715
Enclosure material thermoplastic, red, UL 94 V-0
Place of installation indoor installation
Degree of protection IP 20
Capacity 2 module(s), DIN 43880
Extended technical data: Use in switchgear installations with prospective short-circuit currents of more than 50 kArms (tested by the German VDE)
– Maximum prospective short-circuit current 100 kArms (220 kApeak) 
– Limitation / Extinction of mains follow currents up to 100 kArms (220 kApeak) 
– Max. backup fuse (L) up to IK = 100 kArms (ta ≤ 0.2 s) 500 A gL/gG
– Max. backup fuse (L) up to IK = 100 kArms (ta ≤ 5 s) 315  A gL/gG
Weight 358 g
GTIN 4.01E+12
PU 1 pc(s)
Product Specifications (PDF)