HomeLightning & Surges ProtectionElectronic Systems Protection › Furse ESP SSI Series

Furse ESP SSI Series

Combined Category C, B tested data link protector (to BS EN 61643-21) and Combined Type 2 and Type 3 tested mains protector (to BS EN 61643-11) suitable for Solid State Interlocking (SSI) mains power and data links. Protectors are Network Rail approved.

For use on lines running within buildings at boundaries up to LPZ 1 through to LPZ 3 to protect sensitive electronic equipment.

Features and Benefits

  Accepted for use on Network Rail infrastructure. NRS PADS references: ESP SSI/M - 086/047066; ESP SSI/B - 086/047067; ESP SSI/120AC - 086/047058 and ESP SSI/140AC - 086/047059 (Network Rail Approval PA05/00471)
  Very low let-through voltage (enhanced protection to BS EN 62305) between all sets of conductors - Full Mode protection (ESP SSI/120AC and ESP SSI/140AC) and all signal lines (ESP SSI/M)
  ESP SSI/B modified base unit can be permanently wired into the system
  ESP SSI/M plug-in protection module can be replaced without interfering with the operation of the system
  ESP SSI/B can be flat mounted, or a built-in DIN rail foot allows simple clip-on mounting to top-hat or G DIN rails
  ESP SSI/120AC and ESP SSI/140AC are a compact size for easy installation in trackside cabinets and control rooms
  ESP SSI/120AC and ESP SSI/140AC have three way visual indication of protector status and advanced pre-failure warning

Data Sheet


To prevent transient overvoltage damage to Solid State Interlocking (SSI) systems, protectors should be fitted in trackside cabinets and equipment rooms, on both the data link and the mains power lines.

  For single phase mains power supplies of 90-150 volts, use the ESP SSI/120AC (formerly ESP 120X)
  For single phase mains power supplies of 90-165 volts, use the ESP SSI/140AC (formerly S065)
  For SSI data links, use the ESP SSI/B base unit with the ESP SSI/M protection module

Use ESP PTE002 SSI tester for line-side testing of SSI/M modules.


ESP SSI/B - Connect in series with the data link either near where it enters the trackside location cabinet or the equipment room.

ESP SSI/120AC and ESP SSI/140AC - Install in parallel, within the trackside cabinet or equipment room.

The protector should be installed on the load side of the fuses, at the secondary side of the stepdown transformer.

Connect, with very short leads, to phase (BX), neutral (NX or CNX) and earth.



Please note - Product designs and specifications are subject to change without notice. The user is responsible for determining the suitability of this product.

Back To Last Page


Earthing & Lightning Protection

Electronic Systems Protection (ESP Range)


Ty-Met Stainless Steel Cable Ties

Archive Information

Archive Furse Information

Want A Quotation?

Please fill out the following fields and we will e-mail you a quotation shortly.