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| INSTALLATION | GEOKON
beneficial. For example, if multiple piezometers are installed in a borehole, and
the distance from the borehole to the terminal box or datalogger is great, a
splice (or junction box) could be made to connect the individual cables to a
single multi-conductor cable (see Figure 8). This multi-conductor cable would
then be run to the readout station. For these types of installations, it is
recommended that the piezometer be supplied with enough cable to reach the
installation depth, plus extra cable to pass through drilling equipment (rods,
casing, etc.).
Cable used for making splices should be a high-quality twisted pair type, with
100% shielding and an integral shield drain wire.
When splicing, it is very
important that the shield drain wires be spliced together.
Splice kits
recommended by
GEOKON
incorporate casts that are placed around the splice
and then filled with epoxy to waterproof the connections. When properly made,
this type of splice is equal or superior to the cable in strength and electrical
properties. Contact
GEOKON
for splicing materials and additional cable splicing
instructions.
Junction boxes and terminal boxes are available from
GEOKON
for all types of
applications. In addition, portable readouts and dataloggers are also available.
Contact
GEOKON
for specific application information.
8:
FIGURE 8:
Typical Multi-Piezometer Installation
4.7
LIGHTNING PROTECTION
In exposed locations, it is vital that the piezometer be protected against lightning
strikes. A tripolar plasma surge arrestor, which protects against voltage spikes
across the input leads, is built into the body of the piezometer (see Figure 1).
Additional lightning protection measures available include:
■
Placing a Lightning Arrestor Board (LAB-3), in line with the cable, as close
as possible to the installed piezometer (see Figure 9). These units utilize
surge arrestors and transzorbs to further protect the piezometer. This is the
recommended method of lightning protection.
