Field Applications; Pole Ground Rods - AEMC 3711 User Manual

Field Applications

Pole Ground Rods

Remove any molding covering the ground conductor, and provide
sufficient room for the jaws of the clamp-on. The jaws must be able to
close easily around the conductor. The jaws can be placed around the
ground rod itself.
Note: The instrument must be placed so that the jaws close around an
electrical path from the system neutral or ground wire to the ground rod
or rods as the circuit provides.
Select the current range "A." Clamp onto the ground conductor and
measure the ground current. The maximum range is 30.00A Trms.
However, if the ground current exceeds 5A or noise exceeds 50V,
ground resistance measurements are not possible. Do not proceed
further with the measurement. Remove the instrument from the circuit
noting the location for maintenance and continue to the next test
location.
After noting the ground current, select the ground resistance range (Ω)
and measure the resistance directly. The reading you measure with the
clamp-on tester indicates not just the resistance of the rod, but of the
connection to the system neutral and all bonding connections between
the neutral and the rod.
Note that in Fig. 22 there is both a butt plate and a ground rod. In this
type of circuit, it is necessary to place the instrument above the bond so
that both grounds are included in the test. For future reference, note the
date, ohms reading, current reading and pole number. Replace any
molding you may have removed from the conductor.
Ground Resistance Tester Models 3711 and 3731
Figure 22
- 24 -
rounding
conductor
Utility
round level pole
Butt plate
round
rod