Murray loop test is performed on a faulty cable 300 m long. At balance, the resistance connected to the faulty core was set at 20 Ω and the resistance of the resistor connected to the sound core was 40 Ω. Calculate the distance of the fault point from the test end.

• A. 400 m
• B. 100 m
• C. 300 m
• D. 200 m

Answer: (D)

Where,
R2 is the resistance connected to the faulty core in ohm
R2 is the resistance of the resistor connected to the sound core in ohm

R1 Distance of fault location (Lx) = R2/(R1 + R2)*(2*L)
= (20/60)*600
= 200 m.