5
Figure 5 - A Typical Installation on an Unstable Slope
3.5 Electrical Noise
Care should be exercised when installing instrument cables to keep them as far away as possible
from sources of electrical interference such as power lines, generators, motors, transformers, arc
welders, etc. Cables should never be buried or run with AC power lines. The instrument cables
will pick up the 50 or 60 Hz (or other frequency) noise from the power cable and this will likely
cause a problem obtaining a stable reading. Contact the factory concerning filtering options
available for use with the Geokon dataloggers and readouts should difficulties arise.
3.6 Lightning Protection
The Model 4427 Vibrating Wire Long Range Displacement Meter can be supplied with integral
lightning protection components, i.e. transzorbs or plasma surge arrestors. If the instrument cable
is exposed, it might be appropriate to install lightning protection components, as the transient
could travel down the cable to the gauge and possibly destroy it.
Note the following suggestions;
•
If the gauge is connected to a terminal box or multiplexer components such as plasma surge
arrestors (spark gaps) can be installed in the terminal box/multiplexer to provide a measure of
transient protection. Terminal boxes and multiplexers available from Geokon provide locations
for installation of these components.