OPERATING MANUAL PAT-806 version 1.08
38
During the measurement of a faulty device, RCD switch may be triggered off.
- Differential leakage current is measured as a difference between L current and N current. This
measurement takes into account not only PE leakage current, but also leakage currents caused by
other earthed elements - e.g. water pipe. The disadvantage of this measurement is the influence of
the common current value (flowing to the tested device through line L and returning through line N) on
the accuracy of the measurement. If this current is high, the measurement will be less accurate (as
described in the technical data) than the measurement of PE leakage current.
- Tested device must be turned on.
- In the half-time of the measurement, the meter automatically changes the polarity of the test socket
and as a result it displays the value of higher leakage current.
- The result of measurement may be affected by the presence of external fields and by the current
used by the device.
Note:
The differential method of leakage current measurement is permitted by EN 60974-4
standard as an alternative for measuring the primary leakage current performed during
periodic tests of welding equipment.
4.9 Measurement of touch leakage current
It is recommended for checking the welding equipment to use the measurements: the
leakage current of the primary circuit and leakage current welding circuit.
Press
I
T
. After that meter is prepared for
measurement.
Supply the tested device from mains socket other than PAT (for
Class I the socket must have PE). Additionally connect the probe
which will be used for touching accessible parts of the tested de-
vice (for parts of Class I accessible and not connected to PE).
