Test Procedures
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c.) To locate severed section:
This method uses the core resistance of the heating cable
to approximate the location of a fault when the heating
cable has been severed and the bus wires have not been
shorted together. A severed cable may result in a cold
section of pipe and many not trip the circuit breaker.
A
B
A
B
A
B
Braid
Measure the bus-to-bus heating cable resistance
from the front end (measurement A) and the back end
(measurement B) of the suspect section.
The approximate location of the fault, expressed as a
percentage of the heating cable length from the front
end (A) is:
Fault location: D = 1/A x
100
(1/A + 1/B)
Example:
A = 100 ohms
B = 25 ohms
Fault location: D = (1/100) / (1/100 + 1/25) x 100
= 20%
The fault is located 20% from the front end (A) of
the circuit.
