![background image](http://html.mh-extra.com/html/gmc/f/f_operating-instructions-manual_2235904015.webp)
GOSSEN-METRAWATT
15
5.2
Visual Inspection
Visual inspection is performed prior to measurements with the test instrument.
Visual inspection includes:
•
Housing and protective covers
•
Connections and external cables including fasteners and plugs
•
Visible condition of insulation material
•
Strain reliefs for cables, anti-kink devices and cable routing
•
Fuse links which are accessible to the user (including labeling and inspection
of fuse ratings)
•
Cooling vents and air filters
•
Pressure relief valves
•
Safety relevant labelling
5.3
Measuring Protective Conductor Resistance
The measurement of protective conductor resistance is of course not possible for devices
which are not equipped with a protective conductor (e.g. safety class II and I II devices).
➭
Connect the device under test as described in chapter 4.4, page 11.
➭
Set the measuring range selector switch to the “20
W
” position.
➭
Read the measured value in “
W
” from the LCD.
➭
Move the cable from the DUT during the measurement, section by section over its entire
length, in order to locate interruptions.
Protective conductor resistance may not exceed the following values:
Maximum Allowable Protective Conductor Resistance Values Depending upon Cable Length
Under no circumstances may a value of 1
W
be exceeded. The table is also valid for cable
reels and extension cables.
Attention!
!
The alligator clip (3) must make good contact with the housing of the device under
test!
The connector cable must be moved during measurement, section by section over
its entire length – for permanently installed devices only in so far as the cable is ac-
cessible during repair, modification or testing. If the resistance value fluctuates during
this manual test which is essential for continuity testing, it must be assumed that the
protective conductor is damaged, or that one of its connection points is defective.
Defects of this type must be corrected before any further tests are performed.
Length to [m]
5
12. 5
20
27.5
35
42.5
50
more than 50
Max. resistance [
W
]
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0