Mersen Brand Surge Protection Device STPT2-40K440V-4P


The Mersen Surge Protection Device (SPD) STPT2-40K440V-4P, part of the renowned Surge-Trap® Pluggable STPT2 Series, offers robust and reliable protection against voltage surges. Designed to handle surges up to 40kA, this Type 2 SPD is ideal for use in various electrical systems and commercial applications.


  • Model: STPT2-40K440V-4P
  • Series: Surge-Trap® Pluggable STPT2 Series
  • Type: SPD Type 2, 40kA
  • Voltage Rating: Uc440V
  • Configuration: 4+0 IT;TNS, 4 Poles, 4 Modules, Pluggable
  • Maximum Discharge Current (8/20μs): 40kA per phase
  • Nominal Discharge Current (8/20μs): 20kA per phase

Approvals & Standards

This device complies with the following standards, ensuring high quality and reliability:

  • IEC 61643-11
  • EN 61643-11
  • UL 1449 4th Ed.

Key Features & Benefits

The STPT2-40K440V-4P is engineered for optimal performance and ease of use. Key features include:

  • Type 2/Class II Protection: Suitable for discharging voltage surges in supply distribution panels, either as a second stage of protection with upstream Type 1 devices or as the first stage in less exposed commercial applications.
  • Versatile Network Compatibility: Supports TNS, TNC, TT, and IT networks with various voltage levels including 48V, 60V, 120/208V, 230/400V, 277/480V, and 400/690V.
  • DIN-Rail Mountable & Plug-In Format: Easy installation and maintenance with a plug-in format and DIN-rail mountable design.
  • Visual & Remote End of Life Indicators: Provides clear status updates, ensuring timely maintenance and replacement.
  • Reversible Chassis: Allows for flexible cable entry from either above or below, enhancing installation convenience.
  • Mechanically Coded Cartridges: Prevents cartridge replacement errors, ensuring correct and safe maintenance.
  • Back-Up Fuse: Equipped with a 125 A gG back-up fuse for added safety and protection.


The Mersen STPT2-40K440V-4P is perfect for use in:

  • Supply Distribution Panels: As a second stage of protection where Type 1 devices are installed upstream.
  • Commercial Applications: Ideal for environments not directly exposed to lightning strikes and without external lightning protection systems.


With its robust design, compliance with international standards, and user-friendly features, the Mersen STPT2-40K440V-4P Surge Protection Device is a reliable choice for safeguarding your electrical systems against surges. Its versatility, ease of installation, and comprehensive protection capabilities make it a valuable addition to any electrical network.