Surge arrester T2 40 kA 4P 412243

Surge Protection in TN Networks

This device is designed for installation in distribution boards where surge protection is critical—particularly in installations powered from TN, TN-C, TN-S, and TN-C-S networks. It does not operate in IT or TT systems, so its application must be matched to the specific network type. In practice, this means it is ideal for most modern residential buildings and small commercial facilities, where protection against indirect lightning discharges or switching load impulses is required.

How It Works and What It Provides

It protects equipment by limiting surge voltage to 1.7 kV—this value is sufficient to safeguard household appliances, automation systems, consumer electronics, and other sensitive loads. The discharge current of 20 kA (In) is a standard value for Type 2, while the maximum impulse current of 40 kA (Imax) indicates that the device withstands stronger impulses than many other models in the same class. It has no built-in fuse—therefore, it requires external overcurrent protection (e.g., a 25 A circuit breaker), providing greater flexibility in selecting protection.

Installation and Operation

It mounts on a 35 mm DIN rail—the standard for all modern distribution boards. It occupies 4 modules, allowing easy access and replacement. It connects rigid conductors up to 35 mm² and flexible conductors up to 25 mm²—covering most practical installation cases. Optical signaling (green/orange) indicates operational status without the need to open the enclosure—the installer can immediately see whether the module is still functioning or requires replacement. It has no remote signaling contacts—therefore, it is not suitable for BMS or SCADA systems.

What It Does Not Include

It has no integrated fuse—it cannot be treated as a "standalone" solution. It does not operate in IT or TT networks—if the installation has such a configuration, this model will not be suitable. The IP20 protection rating means it is intended exclusively for installation in enclosed distribution boards—it is not suitable for outdoor use or in humid rooms.

For Whom?

For the installer: simple installation, clear status signaling, compatibility with a wide range of conductors—no need to worry about special tools or connection limitations.
For the user: protects equipment against unexpected surges—for example, after a lightning strike on power lines or during large power spikes in the network.