General Instructions; Connecting The Instrument; Automatic Settings, Monitoring And Shut-Off; Measurement Value Display And Memory - Gossen MetraWatt PROFITEST MBASE MTECH Operating Instructions Manual

5

General Instructions

5.1

Connecting the Instrument

For systems with earthing contact sockets, connect the
instrument to the mains with the test plug to which the
appropriate country-specific plug insert is attached. Voltage
between phase conductor L and protective conductor PE may
not exceed 253 V!
Socket polarity need not be taken into consideration. The
instrument detects the positions of phase conductor L and
neutral conductor N, and automatically reverses polarity if
necessary.
This does not apply to the following measurements:
– Voltage measurement in switch position U
– Insulation resistance measurement
– Low-value resistance measurement
The positions of phase conductor L and neutral conductor N are
identified on the plug insert.
If measurement is to be performed at three-phase outlets,
distribution cabinets or permanent connections, the measuring
adapter must be attached to the test plug (see also table 16.1).
Connection is established with the test probes: one at PE or N
and the other at L.
The 2-pole measuring adapter must be expanded to 3 poles with
the included measurement cable for the performance of phase
sequence testing.
Contact voltage (during RCCB testing) and earthing resistance
can, and earth-electrode potential, standing surface insulation
resistance and probe voltage must be measured with a probe.
The probe is connected to the probe connector socket with a 4
mm contact protected plug.
5.2

Automatic Settings, Monitoring and Shut-Off

The test instrument automatically selects all operating conditions
which it is capable of determining itself. It tests line voltage and
frequency. If these lie within their valid nominal ranges, they
appear at the display panel. If they are not within their nominal
ranges, prevailing voltage (U) and frequency (f) are displayed
instead of U and f .
N N
Contact voltage which is induced by test current is monitored for
each measuring sequence. If contact voltage exceeds the limit
value of 25 V or 50 V, measurement is immediately interrupted.
The U /R LED lights up red.
L L
If battery voltage falls below the allowable limit value, the instru-
ment cannot be switched on or it is immediately switched off.
The measurement is interrupted automatically, or the measuring
sequence is disabled (except for voltage measuring ranges and
phase sequence testing) in the event of:
• Non-allowable line voltages (< 60 V, > 253 V / > 330 V /
> 440 V or > 550 V) for measurements which require line
voltage
• Interference voltage during insulation resistance or low
resistance measurement
• Overheating of the instrument
As a rule, excessive temperatures only occur after
approximately 50 measurement sequences at intervals of
5 seconds, when the rotary selector switch is set to the Z
or Z position.
L-N
If an attempt is made to start a measuring sequence, an
appropriate message appears at the display panel.
The instrument only switches itself off automatically after
completion of an automatic measuring sequence, and after the
predetermined on-time has expired (see section 4.3). On-time is
reset to its original value as defined in the setup menu, as soon as
any key or the rotary selector switch is activated.
The instrument remains on for approximately 75 seconds in
addition to the preset on-time for measurements with rising
residual current in systems with selective RCDs.
The instrument always shuts itself off automatically!
10
5.3

Measurement Value Display and Memory

The following appear at the display panel:
• Measurement values with abbreviations and units of measure
• Selected function
• Nominal voltage
• Nominal frequency
• Error messages
Measurement values for automatic measuring sequences are
stored and displayed as digital values until the next measurement
sequence is started, or until automatic shut-off occurs.
If the upper range limit is exceeded, the upper limit value is
displayed and is preceded by the ">" symbol (greater than), which
indicates measurement value overrun.
Note
The LCD displays shown in these operating instructions
may differ from those of the current test instrument due to
product improvements.
5.4

Testing Earthing Contact Sockets for Correct Connection

The testing of earthing contact sockets for correct connection
prior to protective measures testing is simplified by means of the
instrument's error detection system.
The instrument indicates improper connection as follows:
• Non-allowable line voltage (< 60 V or > 253 V):
The MAINS/NETZ LED blinks red and the measuring sequence
is disabled.
• Protective conductor not connected or potential to earth  50 V
at f  50 Hz (switch position U – single-phase measurement):
If the contact surfaces are touched (finger contact) while PE is
being contacted (via a country-specific plug insert, e.g.
SCHUKO, as well as via the PE test probe at the 2-pole
adapter) PE is displayed. The U
red as well.
* for reliably detecting the contact voltages, both sensor surfaces at
the test plug must be touched directly with the finger/palm without
any skin protection applied, see also section 4.1.
• Neutral conductor N not connected (during mains dependent mea-
surements):
The MAINS/NETZ LED blinks green.
• One of the two protective contacts is not connected:
Testing for this condition is performed automatically for the
RCD functions. Poor contact resistance at one of the contacts
leads to one of the following displays
depending upon plug polarity:
– Display in the connection pictograph:
PE interrupted (x) or lower protective
conductor jumper interrupted with
reference to the keys on the test plug
Cause: voltage measuring path interrupted
Result: measurement is disabled
– Display in the connection pictograph:
Upper protective conductor jumper
interrupted with reference to the keys on
the test plug
L-PE
Cause: current measuring path interrupted
Result: no measured value display
Note
See also "LED Indications, Mains Connections and
Potential Differences" beginning on page 51.
!
Attention!
Reversal of N and PE in a system without RCCBs cannot
be detected and is not indicated by the instrument. In a
system with an RCCB, the breaker is tripped during
"measurement of contact voltage without tripping"
(automatic Z
reversed.
/R and RCD/FI LEDs light up
L L
measurement) if N and PE have been
L-N
GMC-I Messtechnik GmbH