Boltek EFM-100, Installation And Operator'S Manual

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C H A P T E R 2 - I N S T A L L A T I O N
15
permanent
reference
correction

Once you have calculated the required sensitivity reduction (correction factor) you can
calculate the resistor value needed for the Sensitivity Plug.
 


k
correction
k
resistor 100
100
For most installations it is not necessary to correct using a reference field mill. It is usually
sufficient to choose a sensitivity plug which produces a fair-weather electric field of
approximately 0.1 kV/m and does not saturate (above -20 kV/m or +20kV/m) during
most thunderstorms. Electric field trends and sudden changes (lightning) are of much
more interest than an exact absolute value. Alarm setpoints can be lowered to increase
alarm sensitivity or increased to reduce the frequency of nuisance alarms.
Grounding Detail
The EFM-100 field mill needs to be grounded for proper operation and for lightning and
electrical safety. Connect the connector end of the green ground wire to the field mill
ground connector. Connect the other end of the green ground wire and the field mill
mounting hardware to your building’s central ground through a #6 bare ground wire or
other suitable wire according to your local electrical code. Grounding wire and clamps are
available at your local hardware store or electric supplier.
IMPORTANT
The EFM-100 field mill needs to be grounded for proper operation and for
lightning and electrical safety. Connect the field mill green ground wire
and the field mill mounting hardware to your building central ground
through a suitable sized grounding wire according to your local electrical
code.