Description

WITT EPM 100 | Earth potential measuring device – prevention of stray currents and corrosion

Stray currents flow not only along the rails, but also back through the ground, water pipes or other metallic pipework.
These currents can cause metallic components (e.g. pipework, bridge foundations or tunnel reinforcements) to corrode electrochemically – in much the same way as a battery.
Voltage measurement enables dangerous potential differences to be detected at an early stage, allowing countermeasures (e.g. cathodic corrosion protection) to be implemented.

2. Safety for people and animals

Excessive voltage between the rail and earth (or water) can lead to dangerous touch voltages.
This can be life-threatening, particularly in damp or wet environments (e.g. tunnels, bridges, railway stations).
Monitoring ensures that no dangerous voltages occur.

3. Protection of the railway infrastructure

Significant voltage differences can damage the insulation of the railway system or lead to short circuits.
Measuring these voltages minimises such risks and extends the system’s service life.

4. Compliance with standards and regulations

In many countries and among numerous railway operators, regular monitoring of the voltage between the railway track and earth (water earth) is mandatory in order to ensure safety and environmental compatibility.
This is often regulated by law, for example in DIN standards or railway regulations.

5. Early detection of errors

Sudden changes in voltage may indicate insulation faults, faulty return conductors or earthing problems.
Monitoring enables such faults to be quickly pinpointed and rectified before they lead to more serious faults.