16
GOSSEN-METRAWATT
5.4
Measuring Insulation Resistance
This measurement may only be performed if the device under test has successfully completed protective conduc-
tor resistance testing.
This measurement may not be performed if all-pole electrically actuated
switches are included in the device under test.
➭
Connect the device under test as described in chapter 4.4, page 11.
Make sure that the jack (10) is connected to exposed conductive parts at the DUT for safety
class II and III devices.
➭
Set the measuring range selector switch (5) to the “2 M
W
” range (METRATESTER
â
4
only) or the “20 M
W
” range.
➭
Activate all functions of the DUT, and be certain, for example, that contacts for tempera-
ture sensitive switches and the like are also closed.
➭
Read the measured value in “M
W
” from the LCD (11).
Insulation resistance may not fall short of the following values:
The following limit values for insulation resistance may not be fallen short of:
5.5
Measuring Equivalent Leakage Current
According to DIN VDE 0701:2000
, it is absolutely essential to measure protective conductor
current after insulation resistance measurement has been performed. We recommend the
use of an equivalent leakage current measurement.
➭
Connection is the same as shown for the measurement of insulation resistance (see
chapter 5.4, page 16).
➭
Set the measuring range selector switch to the “20 mA” position.
➭
Switch all DUT functions on and make sure, for example, that all contacts for tempera-
ture sensitive switches and the like are closed.
➭
Read the measured value in “mA” from the LCD.
According to DIN VDE 0701:2000, the displayed value for current between components
to which voltage is applied during operation and exposed metal parts may not exceed
3.5 mA, or 1 mA/kW for devices with heating power of greater than 3.5 kW.
Device Type
Limit Value
Minimum Display Value
Safety class I devices
1 M
W
1.105 M
W
(2 M
W
range), 1.15 M
W
(20 M
W
range)
Safety class II devices
with heating elements
0.3 M
W
0.335 M
W
(2 M
W
range), 0.38 M
W
(20 M
W
range)
Safety class II devices
2.0 M
W
2.25 M
W
Safety class III devices
and battery powered devices
1000
W
/V or 250 k
W