User Manual

14 GOSSEN METRAWATT GMBH

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 III devices).

➭ Connect the device under test as described in chapter 4.4, page 10.

➭ Set the function selctor switch to the “R

20 Ω” position.

➭ Read the measured value in “Ω” 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 Ω 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 [Ω] 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0