Geokon 4422, Instruction Manual

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Splice kits recommended by Geokon incorporate casts, which are placed around the splice and
are then filled with epoxy to waterproof the connections. When properly made, this type of splice
is equal or superior to the cable itself in strength and electrical properties. Contact Geokon for
splicing materials and additional cable splicing instructions.
Cables may be terminated by stripping and tinning the individual conductors and then connecting
them to the patch cord of a readout box. Alternatively, a connector may be used which will plug
directly into the readout box or to a receptacle on a special patch cord.
2.5 Lightning Protection
Unlike numerous other types of instrumentation available from Geokon, monument crackmeters
do not have any integral lightning protection components, such as transorbs or plasma surge
arrestors. Usually this is not a problem, however, if the instrument cable is exposed, it may be
appropriate to install lightning protection components, as the transient could travel down the
cable to the gage and possibly destroy it.
Suggested Lightning Protection Options:
•
If the instrument is connected to a terminal box or multiplexer, components such as plasma
surge arrestors (spark gaps) may be installed in the terminal box/multiplexer to provide a
measure of transient protection. Terminal boxes and multiplexers available from Geokon provide
locations for the installation of these components.
•
Lighting arrestor boards and enclosures are also available from Geokon. These units install
where the instrument cable exits the structure being monitored. The enclosure has a removable
top to allow the customer to service the components or replace the board in the event that the unit
is damaged by a lightning strike. A connection is made between the enclosure and earth ground
to facilitate the passing of transients away from the displacement transducer. See
Figure 3.
•
Plasma surge arrestors can be epoxied into the instrument cable, close to the transducer. A
ground strap then connects the surge arrestor to an earth ground, such as a grounding stake or the
rebar itself.
Consult the factory for additional information on available lightning protection.
Figure 3 - Lightning Protection Scheme