a. Attach one lead, either positive
or
negative
of
the
test
set
(resistance meter), to the test ground rod.
b. Then attach the other lead to each of the air terminals, one at a
time.
c. Read the resistance on the meter for each of the air terminals.
d. If the continuity of the system is good, there should be almost no
difference in the value at any of the testing points.
e. If a marked increase is noted, it is an indication that a loose,
corroded, or broken connection exists.
f. If the resistance of all air terminals to ground is high, then a
test can be made at the earth line.
g. Connect the test lead to the down conductor of the system.
This
will measure the resistance of the system ground only.
h. If the resistance is again found to be high, then the system ground
is the cause of the indicated high resistance value.
i. If the resistance is low when the testing lead is connected to the
down conductor, it is an indication of trouble between the original point of
contact on the air terminal and the point of contact on the down conductor.
j. Steps should be taken to reduce all resistances that are above 10
ohms, as indicated in the above procedure.
PART B -INSPECT EQUIPMENT GROUNDING AND CONDUCTIVE FLOORS
1.
The next area
of inspection is the
equipment grounding system and
conductive floors.
a. This system provides a path for static electricity to be carried to
the ground as it is generated.
b. Static electricity is only a hazard when it is allowed to
accumulate.
It could discharge as a spark near highly flammable material
and become a source of ignition.
2.
Work surfaces and equipment in the maintenance building
must
be
grounded even though they are in contact with conductive floors.
8
MM4673
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