HVI Live Line Indicator 3000V DC
The High Voltage DC Live Line Indicator (LLI) is a battery-operated electronic unit specifically designed to test DC systems. It is particularly relevant for Mass Transit Railway (Metro) and Tram-based models. While usually applied to overhead catenaries, it can also be used on "third rail" installations. Verifying that a system is de-energized—and can therefore be safely earthed—is critical for the safety of maintenance staff and overall system security.
Three versions are available to cover the most common system voltages: 750V, 1500V, and 3000V DC.
Operation and Alarms
The DC LLI provides both visual (high-intensity flashing red LEDs) and audible (70dB) alarms if a conductor under test is indicated as live. Each version has a threshold setting of approximately 33% of the system voltage; any voltage above this level deems the line energized.
The unit features a straightforward safety-check sequence:

Arming: Pressing the test button activates the alarms to verify they are working.
Ready State: Upon releasing the button, the red LEDs are replaced by green ones, and the audible alarm stops.
Testing Window: The green "safe to test" condition remains active for approximately 5 minutes. If the unit is applied to a line and the threshold is exceeded during this window, the warning alarms will reactivate.
Battery Check: Pressing the test button also performs an automatic battery health check.

Versatility
A universal "star wheel" adaptor is available to connect the indicator to various operating poles. Additionally, alternative clamps are available to suit different earthing systems, such as buried rails.
Live Line Indicator Kit
Each complete kit comprises:

DC Live Line Indicator with earth lead & clamp
Bowthorpe Rod Adaptor (incorporated into the indicator case moulding)
Universal Star-wheel Adaptor
Hook, Y, and straight electrodes
Polymer Cleaning Kit
Comprehensive Instruction Manual
Durable Carry Satchel