Surge protector DEHNrail M 4P 255 FM, Type 3 953405

Protection for Installations and Equipment with DEHNrail M 4P 255 FM

This four-pole surge protector DEHNrail M 4P 255 FM is a critical component for ensuring electrical safety. Designed for DIN rail TH-35 mm mounting, it effectively protects end devices—especially in industrial environments—from the effects of transient overvoltages. This is a Type 3 device, meaning it excels as a supplementary layer to upstream lightning protection stages.

This surge protector stands out with its high surge current dissipation capacity—up to 8 kA (total discharge current L1+L2+L3+N-PE)—thanks to a combination of zinc oxide varistors and spark gaps. This ensures reliable protection for sensitive electronic components. An integrated optical indicator displays the device’s status, while an additional remote signaling contact enables monitoring of protection status within automation systems.

Key Features and Applications

• Versatile application: Ideal for protecting power circuits supplying industrial electronics in distribution boards.
• Standards compliance: Meets requirements of EN 61643-11, guaranteeing high quality and reliability.
• Easy installation: Mounts on standard DIN rail TH-35 mm, simplifying installation and replacement.
• Status signaling: Optical fault indicator and remote signaling contact allow rapid identification of issues and prompt response.
• Safety: Protected by a fuse rated up to 25 A (gG or B), providing additional protection for the installation.
• Conductor cross-sections: Supports flexible conductors up to 2.5 mm² and rigid conductors up to 4 mm².

Technical Parameters in Practice

The DEHNrail M 4P 255 FM surge protector features a rated AC voltage of 230 V and a rated current of 25 A. Protection levels are 1 kV (L-N) and 1.5 kV (L-PE/N-PE), ensuring effective protection against overvoltages. Notably, the continuous operating voltage (AC) is only 255 V, meaning the device activates at relatively low voltage exceedances, minimizing the risk of damage to connected equipment. The rated discharge current (8/20 µs) is 3 kA for L-N and up to 8 kA for L+N-PE, demonstrating the device’s high efficiency in diverting surge energy.