User's Guide

Chapter 2: Pre-Installation Considerations
RTMS Echo User Guide ©2019 Image Sensing Systems Inc. 2-8
Figure 2-8: Surge Channeled into Earth Ground
Thunderstorm lightning is in its own class of destructive forces to sensors.
Typically, it can generate 30 to 300 kA of current, far beyond the capabilities of
any surge protecting devices. Therefore, a direct or near direct lightning hit
may cause equipment damage even in the presence of surge/transient
protecting devices.
Because lightning is a major influence on power line surge, it is important to
understand the exposure to thunderstorms in the area where the RTMS Echo
sensor is being installed. In areas that are exposed to large number of
thunderstorms, protecting sensors will be more challenging.
Power and comm lines
Surge induced into lines
Lightning discharge
Earth grounding rod
Mounting pole, sensor
and breakout box