TRAFFIC CONTROL TELEPHONE SYSTEMS Circuit - Sam Hallas

Page 58
Earth Fault by Murray Test
Fig. 20.
When using the Murray Earth fault test on a circuit with a branch or
branches, the following procedure must be observed :
Have lines looped at far end of Main Circuit and make test as described
above.
If the earth is on one of the branches, the percentage recorded will give
the junction point of the branch with the main circuit.
The fault may therefore be either at the junction point or on the branch.
The loop should then be removed from the far end of main circuit and
the far end of the branch looped; a further test being made.
The percentage reading obtained will give the approximate location of
the fault by reference to the chart covering the branch concerned.
6. Resistance Measurements by Voltmeter Method. (See Fig. 21).
To measure a resistance other than line resistance, connect resistance to
T1, T3 terminals.