Greenlee 77M-G Instruction Manual page 9

identified, separate the two wires. The signal will be as loud on
each of the pair wires and will NULL halfway between the two
wires.
Figure 4a. Cable Tracing Figure 4b. Pair Tracing
Reception of tone will be strongest on the subject wire(s).
Shorting the leads of a tone carrying wire pair will cancel the
tone signal and also confirm that the pair has been identified. If
you have ready access to bare conductors, a handset or headset
may be used to locate the tone.
CAUTION: Do not connect to an active DC circuit exceeding
52 volts when the test set is in the TONE or OFF position.
Ringing AC voltage will not affect operation.
Testing for Continuity/Shorts Using SHORT Position
Connect the test leads to the subject wire pair. Move the toggle
switch to the SHORT position and note the condition of the
(Line 1) LED. A green LED indicates circuit continuity. The LED
will not illuminate if the circuit resistance exceeds 10 kΩ.
77HP-G only: For resistive shorts of less than 200 Ω, a sounder
will also alert the user of such condition to a short circuit.
CAUTION: Do not connect to any active AC or DC circuit
when the test set is in the SHORT position.
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