Pinpointing Sheath Faults in „ESG“ Mode
85
This is what to do when approaching the fault:
Step Action
1
Find a suitable place to start on the ground directly above the traced cable
route or to the side. Insert the two earth spikes in the correct alignment
positions (see page 82) into the ground.
2
Observe the signals on the indicator unit and try to identify the impulse signal of
the generator.
•
Adjust the scale of the display to the signal level by turning the knob or
activate the automatic scaling (see page 80).
•
If necessary, increase the distance between the earth spikes to receive a
stronger signal level.
•
If the DC impulse of the generator is masked by interference, try to counter
the interference by using some of the available filter functions (see page
80).
•
Switching to the alternative view which shows the voltage curve over the
last 16 seconds (see page 80) could make identifying the periodical DC
voltage impulses easier.
3
Follow the cable route in the direction of the signal without changing your
orientation. Take some more measurements every few metres.
When approaching the fault position, the distance between the earth spikes can
be gradually decreased by up to about one metre with increasing signal levels.
Continue approaching until the signal suddenly changes its polarity and
indicates the opposite direction.
4
Go back slightly and measure the signal level at smaller intervals. Determine
the position at which the opposing currents compensate each other and at
which there is no signal level indicated.
5
To correct any possible lateral offset, insert the two earth spikes at an angle of
90° to the cable route and determine the zero point for the second coordinate
by further measurements.
Procedure