10
10.4
R
4
4
4
4
4
10 Push-button (8455 V3)
This push-button is used for resistance measurements only. While the button is
depressed, the resistance range becomes 1/10 of the dial markings and the
indication is then divided by 10. For example, if the value indicated is less than 10
K
V
, the scale divisions are very small. By depressing the R
4
10 button, 0-10 K
V
is
spread across 1/2 of the scale and a more accurate reading can be obtained. If, in
a ballistic test, the meter pointer kicks off-scale (past 100 POINTS), holding the
R
4
10 button will reduce the “kick” to a readable value.
10.5
Reverse Switch
This switch is primarily for convenience when making ballistic tests. Operating
the switch back and forth transposes the test leads to produce the capacitive
charging “kick” when connected to an open line conductor. It can also be used to
reverse the polarity of the test leads for voltage measurements.
NOTE:
The Instrument can be operated in any convenient position; however,
maximum reading accuracy is obtained with panel in horizontal position as the
Instrument was calibrated in this position.
11.
TEST FOR GROUND
a.
Open conductors toward
Central Office.
b.
Set the Instrument to mea-
sure resistance (ON/OFF
switch to ON; “Press for
Ohms” depressed, 8455A).
c.
Short test clips together and
adjust BATTERY ADJUST-
MENT control for meter
reading of full scale (100
POINTS).
d.
Connect one test clip to ground*.
*GROUND: A connection to metallic cable sheath or wrap, to cable suspension
strand, to ground rod, or to grounded (T) conductor of an adjacent pair.
e.
Connect the other clip to conductor giving a meter deflection.
f.
Note the exact value of resistance indicated. For resistance less than 10 k
V
,
hold R
4
10 button depressed and divide indicated value by 10 (8455 V3).
g.
To calculate distance to fault, refer to Section 17.
12.
TEST FOR SHORT CIRCUIT
a.
Open conductors toward Central Office.
b.
Set the Instrument to measure resistance (ON/OFF switch to ON; “Press for
Ohms” depressed, 8455A).
c.
Short test clips together and adjust BATTERY ADJUSTMENT control for meter
reading of full scale (100 POINTS).
d.
Check both conductors for grounds.
e.
Connect test clips across line pair.
CONDUCTORS OPENED FOR TEST
R
T
FAULT
R
T
TO
STATION
TO
CENTRAL
OFFICE
ON
8455
GROUND
*
Figure11- 1. Test for Ground
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