Innovative technologies for safe handling of electrical power to achieve high availability

Bender products are used worldwide and have been known for more than 65 years.

We offer you first-class quality and safety combined with global service and every support in resolving your monitoring problems.

RS4 Tier 1
RS4 Tier 1

RS4 Tier 1

  • The most advanced of the RS4 solutions
  • For compliance with NR/L2/SIGELP/27725 Tier 1
  • Delivers improved Tier 1 remote fault identification and location at 100KΩ
  • Enables earth fault identification and location at FSP level
  • Compact for use in SIN119 remedial works
  • Available as new or retrofit solution for cost-effective equipment upgrades
  • Bespoke data and communication options tailored to individual projects
  • Eliminates 650V or earth reference requirement making Tier 1 fully class 2
  • Prevent rail downtime through predictive maintenance and fault finding

RS4 Tier 1 is the most advanced of Bender UK’s Rail Signalling Protection Systems.  It delivers the highest level of signal power system insulation monitoring of all the RS4 solutions. It provides full insulation resistance measurement of the system, feeder and individual feeders, monitoring individual subsections of cable and functional supply points (FSP).

Incorporating an earth fault locator (EDS440) and Type B current transformers (CTs) inside FSPs, it evaluates and locates fault sources in a very short time period. The installation in FSP renders the Tier 1 variant class 2 compliant, eliminating the need for earth connection, with all trackside equipment able to be fully integrated into existing FSP enclosures.

The compact and cost-effective RS4 Tier 1 solution is available in 650v mains or 110v supply option, retrofittable to Class 2 and Class 1 equipment, reducing ongoing operational costs. It offers remote fault location to FSP or cable length with exact manual fault finding at 100KΩ.

The RS4 Tier 1 data and communications options can be customised to suit specific projects and customer requirements.


  • Insulation Monitoring and Fault Location Systems used on Signal Power Systems
  • Identifies decline in insulation resistance (IR) values
  • Individual cable sub-section monitoring at FSP level monitoring for Tier 1 compliance
  • Incorporates GSM-enabled data logger equipped for real time direct communication with the Intelligent Infrastructure
  • Immediately identifies earth leakage faults in the power system arising from damaged cables, faulty connections, breaks in insulation, and rodent damage
  • Portable earth fault location system pinpoints location for maintenance teams
  • Delivers enhanced reliability and simplified installation and commissioning
  • Facilitates planned maintenance interventions
  • Dual adjustable insulation alarms – pre-warning and alarm.
  • Standardised for use across Network Rail installations
  • Supplied in self-contained cabinet, tested and ready for ‘plug and play’ installation and commissioning alongside existing power infrastructure systems up to AC 650 V.
  • Integral automatic and manual test facility
  • Lockable front hinged door with viewing window


  • Rail signalling, relay rooms and trackside locations on high priority routes requiring maximum visibility.

Downloads for RS4 Tier 1

Market Segment Brochures Bender Rail Signalling Protection Systems 10.8 MB EN2019/05/13 11:54:5713.05.2019 11:54:57
Flyer Bender UK RS4 Rail Signal Power Protection 2.3 MB EN2019/05/13 14:34:4213.05.2019 14:34:42

RS4 Tier 1 Variants

Bender Part No
RS4 Tier 1