14
GOSSEN-METRAWATT
•
Insulation resistance
for safety class I has been redefined to 1 M
W
, and to 0.3 M
W
for
devices with heating elements. This test is required for all devices for which all charged
insulation is monitored during testing (practically all devices without electrically actuated,
all-pole relays).
The limit values are:
–
Safety class I devices under test:
1 M
W
–
Safety class I DUTs with heating elements:
0.3 M
W
–
Safety class II devices under test:
2 M
W
–
Safety class III devices under test:
0.25 M
W
–
Test voltage (to 0.5 M
W
) 500
V
The limit value for equivalent leakage current has been adapted to the limit value for
protective conductor current. As opposed to the 1993 version of the regulation, the insulation
test must be passed. Measurement of protective conductor current, by means of either the
residual current method or measurement of equivalent leakage current, must always be
performed and passed after insulation resistance measurement.
•
Equivalent Leakage Current
This test must be performed after insulation testing has been passed. The measured
value must be corrected such that it corresponds to the measured value which would
result at line voltage. The METRATESTER
â
performs this function electronically.
The limit values are:
–
3.5 mA for safety class I devices whose exposed conductive parts are all connected
to the protective conductor
–
0.5 mA for devices with exposed conductive parts which are not connected to the
protective conductor
•
Protective Conductor Current
This test is required for all safety class I devices for which insulation resistance cannot be
measured, and for which all exposed conductive parts are connected to the protective
conductor. If non-polarized mains plugs are used, the test must be performed with the
mains plug poled in both directions.
The following test methods are permissible:
–
Direct method
if the device under test is set up under insulated conditions
–
Residual current method
for cases where data transmission cables and gas and water
supply lines cannot be disconnected
Regardless of the test method, the limit values are:
–
1 mA/kW for devices under test with heating elements
and a connected load of greater than 3.5 kW
–
3.5 mA for all other devices under test
•
Contact Current
This test is required for all devices whose insulation resistance cannot be measured, and
which include exposed conductive parts which are not connected to the protective con-
ductor. If non-polarized mains plugs are used, the test must be performed with the mains
plug poled in both directions.
The following test methods are permissible:
–
Direct method
if the device under test is set up under insulated conditions
–
Residual current method
, only possible if no protective conductor is present
The limit value is 0.5 mA for both measuring methods.