Test Procedures
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CAPACITANCE TEST METHOD
This method uses capacitance measurement (nF)
to approximate the location of a fault where
the heating cable has been severed. It also gives
an estimate of total heating cable length in a
non-severed circuit. This reading must be taken
at the power connection and will only work when
the heating cable has passed IR testing. This
information is used to calculate the heating
cable output per linear foot or to determine if
the maximum length has been exceeded.
Record the capacitance reading from one end of the
heating cable. The capacitance reading should be
measured between both bus wires twisted together
(positive lead) and the braid (negative lead).
Multiply the measured capacitance with the heating
cable’s capacitance factor as listed in the following table.
EXAMPLE:
20XTV2-CT
Recorded capacitance = 16.2 nF
Capacitance factor
= 10.1 ft/nF
Fault location
= 16.2 x 10.1 nF
= 164 ft (50 m)
from reading location
As an alternative, capacitance values from both
the front and back end can be used. The ratio of
one capacitance value taken from one end (A)
divided by the sum of both A and B (A + B) and then
multiplied by 100 yields the distance from the first end,
expressed as a percentage of the heating circuit length.