2GMC-I Messtechnik GmbH
1 Safety Features and Symbols
The WZ12 current transformer is manufactured and tested
in accordance with IEC 61010-1 and IEC 61010-2-032
safety regulations. When used for its intended purpose
safety of the operator, as well as that of the instrument, is
assured. Their safety is however not guaranteed, if the
instrument is used improperly or handled carelessly.
In order to maintain flawless technical safety conditions,
and to assure safe use, it is imperative that you read the
operating instructions thoroughly and carefully before plac-
ing your instrument into service, and that you follow all
instructions contained therein.
Observe the following safety precautions:
• The instrument may be used in measuring category II
electrical circuits of up to max. 600 V (phase to neutral
conductor) or in measuring category II I electrical
circuits of up to max. 300 V (phase to neutral conduc-
tor), to 400 V (phase to phase in 4-wire 3-phase
systems) or to 500 V (phase to phase in 3-wire
3-phase systems).
• An open secondary circuit at the WZ12A or WZ12D may
lead to dangerous secondary voltages and to the
destruction of the secondary coil. Make absolutely cer-
tain that the secondary circuit is always connected to the
measuring circuit at the measuring or recording instru-
ment first.
• The secondary circuit may not, at any time, be inter-
rupted due to poor contact at the cables, defective
fuses or interrupted circuits within the measuring
instrument! The current transformer may not be con-
nected to primary current until this condition has been
fulfilled!
(Note: This safety precaution does not apply to models
equipped with voltage outputs (mV/A or mV/mA),
which are supplied with internal matching resistors.)
• Never measure current which exceeds the specified
maximum value.
• The surfaces between the jaws must always be free of
dust or other contamination!
• The clip may only be held at the gripping surfaces
behind the protective collar which have been provided
for this purpose during operation.
