Geokon 4580, Instruction Manual

Page: 11 / 25

5
2.5 Lightning Protection
In exposed locations, it is vital that the transducer 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 transducer. (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 transducer. (See Figure 4.) These units utilize surge arrestors and transzorbs to
further protect the transducer. This is the recommended method of lightning protection.
• Terminal boxes available from Geokon can be ordered with lightning protection built in. The
terminal board used to make the gauge connections has provision for the installation of
plasma surge arrestors. Lightning Arrestor Boards (LAB-3) can also be incorporated into the
terminal box. The terminal box must be connected to an earth ground for these levels of
protection to be effective.
• If the instruments will be read manually with a portable readout (no terminal box), a simple
way to help protect against lightning damage is to connect the cable leads to a good earth
ground when not in use. This will help shunt transients induced in the cable to ground, away
from the instrument.
Transducer Cable
Model 4580 Pressure Transducer
LAB-3
(inside enclosure)
Earth Ground
Figure 4 - Suggested Lightning Protection Scheme