The EXFS 100 gap spark arrester from Dehn + Soehne is a grounding element specifically developed for use in explosive environments. It serves to provide an indirect connection or grounding of operationally separated parts of an installation in the event of a lightning strike. The product is ATEX-certified and suitable for use in Explosion Protection Zone 1 (for gases) and Zone 21 (for dusts). The gap spark arrester meets the requirements for lightning protection equipotential bonding according to DIN EN 62305 and VDE 0185, and features a low triggering voltage, ensuring reliable and early response to overvoltages.

Applications

The EXFS 100 is designed for use in industrial installations where explosion hazards from gases or dusts exist. It is particularly used in areas where electrical installations are operationally separated, but must establish a safe equipotential bonding connection in the event of a lightning strike or overvoltage, without having a direct electrical connection during normal operation. The approval for Zone 1 and Zone 21 makes it suitable for applications in the chemical industry, oil and gas sector, and processing industries.

Functions and Features in Detail

The gap spark arrester operates as an insulating element that prevents electrical contact during normal operation. In the event of overvoltages, such as from a lightning strike, the gap activates at a rated triggering impulse voltage of ≤ 1.25 kV, creating a conductive path to divert the voltage. This prevents damage to installations and protects personnel. The rated withstand AC voltage is 250 V, enabling use in installations with corresponding operating voltages. The gap spark arrester is equipped with M10 threaded screws made of stainless steel 304 (V2A) to resist corrosion and mechanical stress.

Technology Explained Simply

The operation is based on the principle of a spark gap: two electrodes are separated by a defined distance. During normal operation, the current flow is interrupted. During overvoltage, a spark bridges the gap, creating a conductive path. The gap is designed for a lightning impulse current of 100 kA (10/350 µs), indicating high load capacity under extreme overvoltages. The low triggering voltage ensures the gap activates even at relatively low overvoltages, improving protective performance. The IP67 protection rating guarantees dust-tight and waterproof construction, allowing the gap spark arrester to be safely operated outdoors or in humid environments.

Compatibility and Accessories

The EXFS 100 is designed for use in existing grounding systems, particularly in installations already designed according to DIN EN 62305 or VDE 0185. The M10 threaded screws allow universal mounting on various grounding elements. No specific accessories are mentioned in the sources; however, the gap spark arrester is designed as a standalone component to be directly integrated into the grounding infrastructure.

Installation and Mounting

Mounting is done via the integrated M10 threaded screws, which are screwed into suitable mounting points. Installation does not require special tools, but correct positioning within the grounding system must be ensured to guarantee equipotential bonding functionality. The gap spark arrester is designed for an operating temperature range of -40 to 60 °C, enabling use in a wide range of climatic conditions.

Operational Advantages

The EXFS 100 provides reliable protection in explosive environments without establishing an electrical connection during normal operation. The ATEX approval for Zone 1 and Zone 21 enables use in critical installations. The high lightning impulse current capacity of 100 kA and low triggering voltage ensure rapid and effective response to overvoltages. The IP67 protection rating and use of stainless steel 304 for the connection threads enhance durability and resistance to environmental influences.