GOSSEN-METRAWATT
17
4.3
Locating lines and line interruptions in ceilings, walls and floors
Caution!
!
Make sure that the line to be measured is electrically dead.
➭
Connection
:
Connect one socket of the transmitter to ground, the other one to the line
to be tested.
➭
Transmitter
:
Switch the transmitter on and select the required power.
➭
Receiver
:
Select the
open circuit mode
. When searching for the line, proceed as
described under "General procedures for electrically dead lines" on page
16. The signal strength decreases at the point of interruption and be-
yond.
Note
☞
When searching for line interruptions in multiwire cables, note that all wires not used
must be grounded. This is to reduce capacitive couplings into the other lines. To lo-
cate the interruption, the transient resistance must be higher than 100 k
Ω
.
Note that the high-frequency signals for locating of lines are shielded in unfavourable
cases, e.g. by metallic foils or conduits.
Open measuring circuits
With open measuring circuits, the probe head must be held
horizontal to the line as the electric component of the signal is
picked up in this case.
Closed measuring circuits
With closed measuring circuits, the probe head must be held
vertical to the line. In this case, the magnetic component of the
signal is picked up.
