Gossen MetraWatt METRISO 1000 IR User manual

METRISO®1000 IR
Insulation Tester 3-348-712-02
4/1.00
Operating Instructions

2GOSSEN-METRAWATT
(11)(10)(8)(9)(7)(6)(5)(4)
(1)
(2)
(3)
(7)

GOSSEN-METRAWATT 3
(1) Pushbutton for „CONTINUOUSLY ON“
(2) Pushbutton
•for switching to autoranging with ISO-Ωmeasurement,
•for measuring with automatic polarity reversal
with Ωmeasurement and
for switch-on of the lamp in the probe
(3) Pushbutton
•for manual switching to higher measuring ranges
with ISO-Ωmeasurement and
•for Ω-measurement with current direction from + to –
(4) Pushbutton
•for manual switching to lower measuring ranges
with ISO-Ωmeasurement and
•for Ω-measurement with current direction from – to +
(5) LCD display
(6) Rotary switch for function selection
(7) Supports for fastening of the carrying strap
(8) Measurement pushbutton
(9) Fixed probe with lamp (negative pole)
(10) Fixed probe (positive pole)
(11) Pickup clip for attachment to probes
(12) Holder for probe with lamp (9)
(13) Probe holder (10)
(14) Carrying strap
(14)
(12) (13)

4GOSSEN-METRAWATT
Contents
1 Safety precautions .............................................. 5
2 Applications ......................................................... 6
3 Getting started ..................................................... 6
3.1 Inserting the batteries ............................................ 6
3.2 Testing the batteries .............................................. 6
3.3 Fastening the carrying strap and the probe holders .. 8
3.4 Switching the tester on and off ............................... 8
4 LCD display .......................................................... 9
5 Detecting dangerous touch potentials ................ 9
6 Measuring DC and AC voltages ......................... 10
7 Measuring the insulation resistance ................. 11
7.1 ISO-Ωmeasurement up to 3 GΩ
with autoranging .................................................. 11
7.2 ISO-Ωmeasurement up to 3 GΩ
with manual range selection ................................. 14
7.3 Evaluation of the measured values ........................ 15
7.4 ISO-Ωmeasurement up to 30 GΩ ...................... 17
8 Measuring low-ohmic resistances (0 ... 30 Ω) .. 17
8.1 Measuring with automatic polarity reversal ............ 17
8.2 Measuring with manual polarity reversal ................ 18
8.3 Finding the max. display values
regarding the maximum service error: .................. 19
9 Specifications .................................................... 20
10 Maintenance ...................................................... 25
10.1 Messages on the LCD display ............................... 25
10.2 Testing the LCD display ........................................ 25
10.3 Batteries ............................................................. 26
10.4 Fuse ................................................................... 26
10.5 Lamp in the probe ............................................... 27
10.6 Case ................................................................... 27
11 Repair and Replacement Part Service ............... 27
12 Product Support ................................................ 27

GOSSEN-METRAWATT 5
1 Safety precautions
The insulation tester has been constructed and tested to
comply with IEC 61557 / EN 61557 / VDE 0413 und IEC
61010-1 / EN 61010-1 / VDE 0 411-1.
When properly used, the safety of both the user and the
tester is assured. It is not assured, however, if the tester is
misused or carelessly handled.
To maintain the safe and proper condition of the tester and to
ensure Its safe operation, it is absolutely necessary to carefully
and completely read these operating instructions before using the
tester. These instructions must be followed in all respects.
Repair and replacement of parts
When opening the tester, live parts may be exposed. The
tester must be disconnected from all voltage sources prior
to repair or replacement of parts. If a repair cannot be
avoided unless the tester is open and live, this must only be
performed by a qualified person who understands the dan-
ger involved.
Faults and extraordinary stress
When it must be assumed that safe operation is no longer
possible, take the tester out of service and secure it against
accidental use. It is assumed that safe operation is no
longer possible,
• when the tester shows obvious signs of damage,
• when the tester no longer functions correctly,
• after prolonged storage under adverse conditions,
• after severe transport stress.
Attention!
!
The fixed test leads have a double insulation in dif-
ferent colors. You can readily recognize damaged
leads by the light insulation on the inside.
The VDE Test Office has approved the use of the VDE-GS
mark (tested safety) for the insulation tester.
Meaning of the symbols on the device
Warning of a danger point
(Attention, refer to documentation)
Double or
reinforced all-insulation
Mark approval
by testing board
EU-Conformity Mark
!

6GOSSEN-METRAWATT
2Applications
The insulation tester complies with the following specifications:
IEC 61557 / EN 61557 / VDE 0413 “Measuring and moni-
toring facilities for testing the electrical safety in lines with
nominal voltages up to AC 1000 V and DC 1500 V“.
Part 1 „General“;
Part 2 „Insulation resistance“;
Part 4 „Resistance measuring devices“.
It is suited to measure the insulation resistance of electrically
dead devices and systems having nominal voltages up to
1000 V and to test the resistance of ground conductors,
protective conductors and equipotential conductors includ-
ing their connections and connectors.
In addition, the fester has a 1000 V measuring range for
DC and AC voltage which complies with DIN VDE 0100
Part 610. This makes it particularly advantageous to test
devices for the absence of voltage and to discharge capac-
itive devices under test.
The most important applications of the insulation tester are
found in testing of systems and appliances such as required
by DIN VDE 0100, 0 105, 0141, 0701 and 0702 specifica-
tions, for example. Furthermore, it is possible to perform a
„test of the discharge capability for electrostatic charges for
floor coverings in explosion-hazardous rooms“ according to
DIN 51 953.
3 Getting started
3.1 Inserting the batteries
Attention!
!
Make sure that the rotary switch (6) is set to the
„OFF“ position prior to opening the battery com-
partment and that the tester is completely discon-
nected from all external circuits!
íUndo the two slotted screws on the bottom of the tester
with an adequate tool and remove the cover of the bat-
tery compartment.
íInsert 6 each 1.5 V mono-cells to IEC R20 (zinc-carbon)
or to IEC LR20 (alkaline-manganese) in the battery com-
partment, paying attention to the correct polarity in line
with the given symbols.
íReplace the cover of the battery compartment and
tighten the screws.
3.2 Testing the batteries
When measuring the insulation resistance, the load on the
batteries is different on the three nominal voltage ranges.
That means, for example, that the „charging state“ of the
six mono-cells no longer assures compliance with the error
limits at a nominal voltage of 1000 V while many measure-
ments can still be made with the specified accuracy at
250 V. That is why the tester offers the possibility to test the
batteries under operating conditions for each of the three
nominal voltages. The lamp in the probe is on at times.

GOSSEN-METRAWATT 7
Test for nominal voltage 500 V and for the „Ω“ range:
íSet the rotary switch (6) to position „-Il-“.
The digital display shows the battery voltage at a simulated
load for the 500 V nominal voltage on the LCD display (5).
At the same time, the analog indicator shows the nominal
range of use of the battery voltage. You can quickly judge
the charging state of the battery set by the location of the
pointer.
The battery test for the nominal voltage 500V and for the
„Ω“ range is recognized by two superimposed horizontal
lines preceding the digital display.
Test for nominal voltages 250 V and 1000 V:
íSet the rotary switch (6) to position „-I|-“ as described
above.
íFor the test of the nominal voltage 250 V, briefly press
the „RANGE↓“ pushbutton (4), or briefly press the
„RANGE↑“ pushbutton (3) for the test for the nominal
voltage 1000„RANGE↑“V.
The battery voltage is displayed in digital and analog form,
as described above.
For recognition, a horizontal line precedes the digital display
for 250 V nominal voltage and three superimposed lines for
1000 V nominal voltage.
If the battery test reveals that the battery voltage is below
the lower limit, „U LO“ is shown on the LCD display (5).
The battery test is automatically stopped after about
10 seconds. „HOLD“ is shown on the LCD display (5) in
addition to the digital display and the analog indication.
This presentation is maintained until the tester automatically
switches back to „standby“ after approximately 3 minutes,
until you press the measurement pushbutton (8) or until you
set the rotary switch (6) to another position.
You start a new battery test by pressing the measurement
pushbutton (8).

8GOSSEN-METRAWATT
3.3 Fastening the carrying strap and the probe holders
Fasten the carrying strap
(14) and the two probe
holders (12) and (13) as
shown in the following fig-
ure. Make sure to fix the
holder for the slim probe
(10) at the left and the
holder for the probe with
lamp and pushbutton (9) at
the right.
3.4 Switching the tester on and off
„Standby“ for minimum power consumption
íSet the rotary switch (6) from the „OFF“ position to posi-
tion „1000 V “, to one of the „ISO-Ω“ or to the „Ω“
position.
When set to the „1 000 V “ position, the measuring range for
DC and AC voltage is switched on. Digital display and ana-
log indication are presented.
When set to one of the three „ISO-Ω“ positions, the tester is
switched to „standby“. The digital display only shows the
decimal point together with the numeral 3 and the unit MΩ,
and the analog indicator shows the measuring range 500 V
or 1000 V in line with the selected nominal voltage. 500 V
are displayed in the 250 V range.
When set to the „Ω“position, the tester is switched to
„standby“.The digital display only shows the decimal point
together with the number 30 and the unit „Ω“.
After measuring at the „Ω“ and „ISO-Ω“ positions, the tester
automatically switches to „standby“,
• when the rotary switch is not operated for approximately
3 minutes and when no pushbutton is pressed
• when the measured values does not change for approxi-
mately 3 minutes
• when no voltage above 25 V is applied to the probes for
more than 3 minutes on the „1000 V “range
íTo reactivate the tester, press any pushbutton on the
tester or the pushbutton (8) in the probe, or set the
switch (6) to another position.
Probe holder
Carrying strap
Catch
METRISO

GOSSEN-METRAWATT 9
„CONTINUOUSLY ON“
When set to the „ISO-Ω“ and „Ω“ positions, the tester
measures only as long as you keep the pushbutton (8) in
the probe pressed (an exception is the „AUTO“ function at
position „Ω“, see section 8.1). When set to these positions,
you also can switch the tester „CONTINUOUSLY ON“:
íBriefly press the measurement pushbutton „( )“ (1) on
the tester. You can cancel „CONTINUOUSLY ON“ by
• again pressing the measurement pushbutton „ “ (1) on
the tester
• pressing the pushbutton (8) in the probe
• operating the rotary switch (6)
Note!
☞
Electrical discharges and high-frequency interfer-
ences can cause incorrect displays. Briefly set the
rotary switch (6) to another position; the tester is
thus reset.
4LCDdisplay
The measured values are shown on the LCD display (5) in
digital and analog form.
The digital display shows the measured value with decimal
point and unit. The numerals immediately under the decimal
points show the upper limit of the selected measuring
range. When the measuring range is exceeded, „OL“ is dis-
played in place of the measured value.
The analog indicator with pointer presentation gives the
dynamic response of a moving-coil movement. The analog
display is of particular advantage when observing variations
of measured values and transients.
When the upper range limit is exceeded, a triangle is shown
at the end of the analog scale.
5 Detecting dangerous touch potentials
The tester detects dangerous touch potentials on the probes
• regardless of being switched on or not
• regardless of the selected function
• regardless of the batteries being inserted or not.
Voltages above 25 V are
signalled on the LCD dis-
play (5) by a warning tri-
angle.
The display of the warn-
ing triangle is made with-
out auxiliary voltage. You can recognize the triangle already
from approximately 10 V up with low contrast. Full contrast
is obtained at 25 V.
The warning triangle directs your attention to a hazardous
voltage on the probes. You can determine the voltage value
on the voltage measuring range.
Attention!
!
When the rotary switch (6) is set to the „Ω“ posi-
tion, the fuse blows when an external voltage is
applied to the probes!
Never switch to the „Ω“ range when an external
voltage is applied as this could damage the switch
contacts!

10 GOSSEN-METRAWATT
6 Measuring DC and AC voltages
Set the rotary switch (6) to the „1000 V “ position.
íScan the measuring points with the two probes without
pressing the measurement pushbutton (8) in the probe.
The tester alternately measures the DC and the AC voltage
and displays the higher measured value in both digital and
analog form. The symbol behind the „V“ character shows
whether a DC or an AC voltage is displayed.
When the measured value is steady, the word „DATA“ is
shown on the LCD display. A short sound signal points to
this.
íWhen you briefly press the measurement pushbutton (8)
in the probe, the word „HOLD“ is displayed in addition to
„DATA“ and the measured value on the digital display is
held.
If, after storage of the measured value, the voltage drops to
a value below 10 V, the held measured value is cleared the
instant the voltage rises again and „DATA HOLD“ is
blanked.
The digital display then again shows the actual measured
value. The measured value can be held as soon as it has
reached a steady state again.
If you press the measurement pushbutton (8) even though
the measured value is not (yet) stable, only „HOLD“ is
shown and not „DATA“. When pressing the measurement
pushbutton the currently existing measured value is held on
the digital display. The pointer of the analog indicator con-
tinues to constantly follow the actual measured value.
íWhen pressing the pushbutton again, you clear the
measured value. The digital display then shows the
actual measured value.
íYou can use the lamp in the probe (9) to illuminate the
measuring point or the LCD (5). Press the pushbutton
„AUTO / ⊗“ (2). The lamp lights as long as you keep the
pushbutton (2) pressed.
Note!
☞
The permissible overload capacity on the voltage
measuring range is 1200 V .
If this value is exceeded, a sound signal draws
your attention to it.
The input resistance on the voltage measuring
range is 880 kΩ. With a blown or a missing fuse,
the voltage measurement is made with an input
resistance of approximately 5 MΩ.

GOSSEN-METRAWATT 11
7 Measuring the insulation resistance
7.1 ISO-Ωmeasurement up to 3 GΩwith autoranging
íSet the rotary switch (6) to one of the three „ISO-Ω“ posi-
tions. Depending upon the nominal voltage of the device
under test, you can measure the insulation resistance
with a nominal voltage of 250 V, 500 V or 1000 V. With a
nominal voltage of 1000 V selected, the LCD display (5)
shows the following:
When there is no voltage applied to the probes, the digital
display only shows the decimal point together with the
numeral 3 and the symbol for the unit MΩ. Depending upon
the nominal voltage selected, the analog indicator shows
the 250 V, 500 V or 1000 V measuring range.
When the „ISO-Ω“ function is switched on, or when chang-
ing to this function, the tester always switches to autorang-
ing. The LCD then shows „AUTO“.
Detecting external voltages
You can measure insulation resistances on electrically dead
devices only. That is why it is necessary to detect external
voltages.
íApply the two probes to the measuring points. If a
voltage > approximately 25 V exists, the presentation on
the LCD display (5) changes as follows:
• The warning triangle signals a hazardous contact poten-
tial > 25 V.
• Four horizontal lines are shown in the middle of the
numerals of the digital display.
• The pointer of the analog indicator shows the value of
the DC or AC voltage applied. If this is the voltage of a
charged capacitive device under test, the device under
test is discharged. You can observe the drop in voltage
on the analog indicator.
If the measurement pushbutton (8) is already pressed
before you apply the probes to the measuring points – e.g.
to illuminate the measuring points – a sound signal points to
an external voltage on the device under test.

12 GOSSEN-METRAWATT
Starting the measurement
Attention!
!
An insulation measurement is blocked when a
voltage > 25 V is applied to the probes prior to
starting the measurement! A short sound signal
points to this.
íPress the measurement pushbutton (8) in the probe and
hold it at this position.
The display switches to ISO-Ωmeasurement with the fol-
lowing presentation:
Digital display: In line with the measured value, the tester
selects that measuring range from the 6 automatically
selectable ISO-Ωmeasuring ranges with which the best
resolution is obtained. When the measured value changes,
it automatically switches:
– to the next higher range at 3199 digits + 1 digit
– to the next lower range at 300 digits –1 digit
Overrange „OL“ is signalled, when the meas. value is higher
than 3 GΩ. You can measure insulation resistances up to
30 GΩafter manual range selection acc. to section 7.4!
Analog indication: The entire measuring span of the ISO-Ω
measurement (all of the 6 automatically selectable measur-
ing ranges) is shown on the analog scale in logarithmic
scale in coherent form. This makes for changes in meas-
ured value to be quickly detected and observed over sev-
eral measuring ranges. With measured values below 3 kΩ,
a triangle is shown at the left end of the analog scale in
place of the pointer. With a measured value of more than
3G
Ω, overrange is signalled by a triangle at the right end of
the scale. You can measure insulation resistances up to
30 GΩafter manual range selection according to section
7.2!
Lamp in the probe (9): The lamp functions as long as you
press the pushbutton in the probe. It illuminates the meas-
uring point when the measured insulation resistance is
> approx. 500 kΩon the nominal voltage range 250 V,
> approx. 1 MΩon the nominal voltage range 500 V and
> approx. 2 MΩat a nominal voltage of 1000 V. The lamp
does not light with measured values that are smaller than
the given values.
It thus serves for a quick Good-Bad judgement of the insu-
lation resistance. As long as the lamp lights, the minimum
indication values of the insulation resistance according to
DIN VDE 0100 are definitely not fallen below.
You can switch the lamp on to illuminate the measuring
point even if the insulation resistance is lower than the val-
ues given for the lamp switching point.
Press the „AUTO/⊗“ pushbutton (2). The lamp lights as
long as you keep the pushbutton pressed.
Sound signal: Insulation resistances < 2 kΩare reported by a
sound signal which ceases at values > 6 kΩ.

GOSSEN-METRAWATT 13
Attention!
!
Do not touch the probe ends (9) and (10) when the tester
is switched on for ISO-Ωmeasurement. When the
probe ends are free or connected to an ohmic
device under test, a current of up to 1 mA would
flow through your body at a voltage of 250 V,
500 V or 1000 V. The electrical shock is noticea-
bly felt but the current does not reach hazardous
values.
If, however, you measure on a capacitive device
under test, e.g. on a cable, this can charge up to
about 250 V, 500 V or 1000 V, depending upon
the nominal voltage selected. Touching means dan-
ger to life! For that reason, discharge with caution
as described before.
Holding the measured value
When the measured value is steady, „DATA“ is displayed on
the LCD display (5). A brief sound signals this state.
íYou can read the measured value now – or after releas-
ing the measurement pushbutton (8).
íNow release the measurement pushbutton (8) in the
probe.
The word „HOLD“ is displayed in addition to „DATA“, and
the measured value on the digital display is held.
If you release the pushbutton even though the measured
value is not (yet) steady, „HOLD“ is displayed instead of
„DATA“. When releasing the pushbutton, the measured
value shown on the digital display is held.
íContinue to contact the measuring points with the two
probes.
After releasing the measurement pushbutton, the voltage
scale is again shown on the analog indicator. After having
measured the insulation resistance of a capacitive device
under test, the latter discharges automatically. You can
observe the drop in voltage on the pointer of the analog
indicator.
Remove the connection to the device under test only when the
warning triangle „V“ is no longer shown! It is only then that
the voltage across the device under test is no longer haz-
ardous.
íThe measured value hold in the digital display is cleared
approximately 3 minutes after releasing the measure-
ment pushbutton (8) and the tester switches to
„standby“.
íThe lamp in the probe (9) is a helpful means to read the
LCD at poor light conditions. The lamp lights as long as
you keep the pushbutton „AUTO /⊗“ (2) pressed.
Repeating the measurement
íPress the measurement pushbutton (8) in the probe and
hold it at this position. New measured values are immedi-
ately shown. The previously held value is cleared.

14 GOSSEN-METRAWATT
7.2 ISO-Ωmeasurement up to 3 GΩwith manual range selection
íSet the rotary switch (6) to one of the three „ISO-Ω“ posi-
tions. Depending upon the nominal voltage of the device
under test, you can measure the insulation resistance
with a nominal voltage of 250 V, 500 V or 1000 V.
íCheck that the device under test is free from external
voltages as described for the measurement with auto-
ranging in section 7.1.
íBriefly press one of the two pushbuttons „RANGE↑“ (3)
and „RANGE↓“ (4).
You thus leave autoranging and fix the 3 MΩmeasuring
range. The tester always selects this output range when
you set the rotary switch (6) to one of the three „ISO-Ω“
positions. The LCD shows the word „RANGE“ in place of
„AUTO“.
íYou now can select the measuring ranges manually with
the two pushbuttons (3) and (4). Each time you press the
pushbutton „RANGE↑“ (3) you switch to the next higher
measuring range, each time you press the pushbutton
„RANGE↓“ (4) you switch to the next lower range.
You can recognize the measuring range selected on the
LCD by the numerals immediately under the decimal
points and by the unit.
íApply the two probes to the measuring points.
íPress the measurement pushbutton (8) in the probe (9)
and hold it at this position. The measured value is dis-
played in digital and analog form on the selected meas-
uring range, regardless of its magnitude. Now the analog
scale is linear.
Depending upon the measured value and the selected
measuring range, it is possible that measured values are
not displayed with optimum resolution or with overrange
display („OL“ and/or triangle at the end of the analog
scale).
íNow release the measurement pushbutton (8) in the
probe.
The measured value is held same as described in
section 7.1 for the measurement with autoranging.
As the measurement of the insulation resistance is
always made with maximum resolution, you now can
select the range which displays the measured value with
optimum resolution, using the pushbuttons „RANGE↑“
(3) and „RANGE↓“ (4).

GOSSEN-METRAWATT 15
Example
You measure an insulation resistance of 179.3 kΩon the
300 MΩmeasuring range at a nominal voltage of 1 000 V.
The following is shown on the LCD display (5):
Then switch to the 300 kΩmeasuring range. The display
changes as follows:
íWith manual range selection, all features of the tester, as
described in section „7.1 ISO-Ωmeasurement up to
3G
Ωwith autoranging“, apply analogously.
íThe tester switches back to autoranging when you briefly
press the pushbutton „AUTO /⊗“ (2).
7.3 Evaluation of the measured values
So that the limits of the insulation resistance required by
DIN VDE specifications are not fallen below under any con-
dition, the measuring error of the insulation tester must be
considered. The required minimum display values for insula-
tion resistances which may be indicated with consideration
of the maximum service error of the insulation tester (under
nominal conditions of use) without exceeding the specified
limits (DIN VDE 0413 Part 1) can be found from the follow-
ing table. Intermediate values can be interpolated.
The service error is different on the three nominal voltages
ranges. That is why different minimum display values must
be considered, depending upon the selected nominal volt-
age.

16 GOSSEN-METRAWATT
Minimum display values of insulation resistances (on the nominal range of use) at specified limits
Range 300 kΩRange 3 MΩRange 30 MΩRange 300 MΩ
Limit Min. display value (kΩ)
at nominal range
Limit Min. display value (MΩ)
at nominal range
Limit Min. display value (MΩ)
at nominal range
Limit Min. display value (MΩ)
at nominal range
kΩ250 V 500 V 1000 V MΩ250 V 500 V 1000 V MΩ250 V 500 V 1000 V MΩ250 V 500 V 1000 V
0.2 0.210 0.206 0.208 2 2.10 2.06 20.8 20 21.0 20.6 20.8
0.3 0.315 0.309 0.312 3 3.15 3.09 3.12 30 30.5 30.9 31.2
0.4 0.420 0.412 0.416 4 4.20 4.12 4.16 40 42.0 41.2 41.6
0.5 0.525 0.515 0.520 5 5.25 5.05 5.20 50 52.5 50.5 52.0
0.6 0.630 0.618 0.624 6 6.30 6.18 6.24 60 63.0 61.8 62.4
0.7 0.735 0.721 0.728 7 7.35 7.21 7.28 70 73.5 72.1 72.8
0.8 0.840 0.824 0.832 8 8.40 8.24 8.32 80 84.0 82.4 83.2
0.9 0.945 0.927 0.936 9 9.45 9.27 9.36 90 94.5 92.7 93.6
100 105.0 103.0 104.0 1.0 1.050 1.030 1.040 10 10.50 10.30 10.40 100 105.0 103.0 104.0
110 115.5 113.3 114.4 1.1 1.155 1.133 1.144 11 11.55 11.33 11.44
120 126.0 123.6 124.8 1.2 1.260 1.236 1.248 12 12.60 12.36 12.48
130 136.5 133.9 135.2 1.3 1.365 1.365 1.339 13 13.65 13.39 13.52
140 147.0 144.2 145.6 1.4 1.470 1.442 1.456 14 14.70 14.42 14.56
150 157.5 154.5 156.0 1.5 1.575 1.545 1.560 15 15.75 15.45 15.60
160 168.0 164.8 166.4 1.6 1.680 1.648 1.664 16 16.80 16.48 16.64
170 178.5 175.1 176.8 1.7 1.785 1.751 1.768 17 17.85 17.51 17.68
180 189.0 185.4 187.2 1.8 1.890 1.854 1.872 18 18.90 18.54 18.72
190 199.5 195.7 197.6 1.9 1.995 1.957 1.976 19 19.95 19.57 19.76
200 210.0 206.0 208.0 2.0 2.100 2.060 2.080 20 21.00 20.60 20.80
210 220.5 216.3 218.4 2.1 2.205 2.163 2.184 21 22.05 21.63 21.84
220 231.0 226.6 228.8 2.2 2.310 2.266 2.288 22 23.10 22.66 22.88
230 241.5 236.9 239.2 2.3 2.415 2.369 2.392 23 24.15 23.69 23.92
240 252.0 247.2 249.6 2.4 2.520 2.472 2.496 24 25.20 24.72 24.96
250 262.5 257.5 260.0 2.5 2.625 2.575 2.600 25 26.25 25.75 26.00
260 273.0 267.8 270.4 2.6 2.730 2.678 2.704 26 27.30 26.78 27.04
270 283.5 278.1 280.8 2.7 2.835 2.781 2.808 27 28.35 27.81 28.08
280 294.5 288.4 291.2 2.8 2.940 2.884 2.912 28 29.40 28.84 29.12
290 304.5 298.7 301.6 2.9 3.045 2.987 3.016 29 30.45 29.87 30.16
300 315.0 309.0 312.0 3.0 3.150 3.090 3.120 30 31.50 30.90 31.20

GOSSEN-METRAWATT 17
7.4 ISO-Ωmeasurement up to 30 GΩ
You can measure insulation resistances on the 30 GΩ
measuring range only at a nominal voltage of 500 V or
1000 V and after manual range selection.
íProcede first as described in section „7.2 ISO-Ωmeas-
urement up to 3 GΩwith manual range selection“.
íThen select the highest measuring range 30 GΩwith the
„RANGE↑“pushbutton (3).
íMake a solid connection of the test leads to the device
under test using the included alligator clips and make
sure the test leads do not touch each other. It is of
advantage to run the test leads to the device under test
as „free leads“. You can thus prevent the parallel insula-
tion resistance of the test leads from affecting the meas-
ured result.
íStart the measurement by briefly pressing the measure-
ment pushbutton „“(1).
This also is a measure to prevent the measured result
from being affected by touching of the probes.
íWhen the LCD display (5) shows „DATA“and a brief
sound signal draws your attention to this, you can end
the measurement by again pressing the pushbutton „“
(1), read and hold the measured value (see „Holding the
measured value“in section 7.1).
8 Measuring low-ohmic resistances (0 ... 30 Ω)
8.1 Measuring with automatic polarity reversal
Attention!
!
Verify that the device under test is electrically
dead, e.g. by means of a voltage measurement,
before you perform measurements on the low-
ohmic measuring range. The fuse blows, when a
voltage source of a sufficiently high energy yield is
connected!
íSet the rotary switch (6) to the „Ω“position.
The LCD display (5) only shows the decimal point
together with the number 30 and the unit Ω. The analog
scale is blanked.
íStart measuring by briefly pressing the measurement
pushbutton (8) in the probe (9) or the pushbutton (1).
„CONTINUOUSLY ON“with the measurement pushbut-
ton „“(1) is not possible when measuring with auto-
matic polarity reversal. The tester now automatically
measures first in one direction of the current and then in
the other. The LCD display first shows the arrow at the
left and then the arrow at the right of the „Ω“character.
The right arrow signals a direction of the current from „+“

18 GOSSEN-METRAWATT
to „–“ in line with the imprinted polarity symbols on the
front of the tester. Display of the left arrow signals the
ongoing measurement with opposite direction of the cur-
rent.
After a measurement cycle, the higher of the two measured
values is shown in digital form together with the word
„HOLD“. A brief sound signal draws your attention to the
end of the automatic measurement.
If the measured results for both current directions deviate
from each other by more than 10% –this corresponds to the
permissible service error –both measured values are dis-
played side by side with reduced resolution, e.g. as follows:
This presentation of the measured values informs you that
the measurement with automatic polarity reversal does not
give an unambiguous display, e.g. with a high contact
resistance at the contact points. In this case, measure the
resistance with manual polarity reversal according to the fol-
lowing description.
8.2 Measuring with manual polarity reversal
íBriefly press the „Ω→“pushbutton (3) or the „Ω←“push-
button (4). You thus select the direction of the current
with which you want to measure.
íStart measuring by pressing the measurement pushbut-
ton (8) in the probe (9) and hold the pushbutton at this
position. You may also start measuring by pressing the
measurement pushbutton „“(1) on the tester.
Now the measurement is made in the selected direction
of the current. You can recognize the direction on the
LCD display by the corresponding arrow next to the
„Ωcharacter“.
The measured value is shown in both digital and analog
form. With measured values of more than 3.0 Ω, the analog
indicator shows overrange. In this case, the triangle is
shown at the right end of the analog scale. The digital dis-
play shows measured values up to 30 Ω.
„DATA“and „HOLD“function same as with ISO-Ωmeasure-
ment.
When the lamp in the probe (9) lights, it shows you that the
measured values are smaller than 0.3 Ω(limit according to
DIN VDE). The lamp serves for a quick, optical continuity
test.
íNow measure the resistance with reversed direction of
the current.

GOSSEN-METRAWATT 19
Different results obtained when measuring in both directions
of the current point to external voltages on the device under
test (e.g. thermovoltages or element voltages). Particularly
in systems where the protective means „overcurrent protec-
tive device“(formerly null method) is used without a sepa-
rate protective conductor, the measured results can be
falsified by impedances of operating circuits connected in
parallel and by equalizing currents. To obtain unambiguous
measured results, it is required to eliminate the cause of the
fault.
íWhen you briefly press the pushbutton „AUTO /⊗“(2),
the tester switches back to resistance measurement with
automatic polarity reversal.
Notes on measuring low-ohmic resistances:
•A low-ohmic measurement is made in four-wire connec-
tion, whereby the leads are run up to the probes. The
resistance of the fixed test leads does not enter into the
measured result for that reason. If you use an extension
cord, you must measure its resistance and deduct this
value from the measured value obtained.
•To also enable the measurement of larger resistances as
required by DIN VDE 0413 Part 4, the measuring span of
the digital display is larger by one decade (up to 30 Ω)
than that of the analog indicator (up to 3 Ω).
•On the low-ohmic measuring range, the tester is pro-
tected against overload by a superquick-acting fuse
FA 0.315 A /1000 V. With a blown fuse, only the voltage
measuring range functions (Ri= 5 MΩ). When you press
the measurement pushbutton in the „Ω“function, the
word „FUSE“is shown in place of the digital display.
•Resistances that reach a stable value only after a „tran-
sient response“should only be measured after manual
selection of the direction of the current. A measurement
with automatic polarity reversal can lead to different and
to higher measured values and thus to an ambiguous
display.
Resistances whose values change at the beginning of the
measurement, are, for instance:
•Resistances having a high inductive content
•Resistances of light bulbs whose values change due to
heating caused by the measuring current
•Poor contact resistance at the contact points.
8.3 Finding the max. display values
regarding the maximum service error:
Limit ΩMax. display values Ω
0.2 0.16
0.3 0.25
0.4 0.35
0.5 0.44
0.6 0.53
0.7 0.62
0.8 0.71
0.9 0.80
1.0 0.89
1.5 1.35
2.0 1.80
2.5 2.25
3.0 2.71
3.5 3.16
4.0 3.62

20 GOSSEN-METRAWATT
9 Specifications
1) Last digit is balanked; range span 300 digits
2) rdg. = of reading
3) Error of analog indicator = error of digital display ±1 pointer
4) at –10 °C ... +55 °C
Measuring
function
Measuring
range Resolution
Intrinsic error under
reference conditions
2) 3)
Nominal range
of use
Service
error
Overload capacity 4)
Overload
value
Overload
duration
1000 V 0 ... 1000 V 1 V ±(2.0% rdg. + 2D) 50 V ... 1000 ±3.5% 1200 V AC DC continuously
ISO-Ω
UN=
250 V
0 ... 30 KΩ
0 ... 300 KΩ
0 ... 3 MΩ
0 ... 30 MΩ
0 ... 300 MΩ
0 ... 3 GΩ1)
10 Ω
100 Ω
1KΩ
10 KΩ
100 KΩ
10 MΩ
±( 1.5% rdg. + 2D)
±( 1.5% rdg. + 2D)
±( 1.5% rdg. + 2D)
±( 1.5% rdg. + 2D)
±( 3.0% rdg. + 2D)
±(20.0 % rdg. + 2D)
100 kΩ ...
100 MΩ
(AUTO)
±5% 1200 V AC DC max. 10s
ISO-Ω
UN=
500 V
0... 30 kΩ
0 ... 300 kΩ
0 ... 3 MΩ
0 ... 30 MΩ
0 ... 300 MΩ
0 ... 3 GΩ1)
0 ... 30 GΩ1)
10 Ω
100 Ω
1kΩ
10 kΩ
100 kΩ
10 MΩ
100 MΩ
±( 1.5% rdg. + 2D)
±( 1.5% rdg. + 2D)
±( 1.5% rdg. + 2D)
±( 1.5% rdg. + 2D)
±( 1.5% rdg. + 2D)
±( 3.0% rdg. + 2D)
±(20.0 % rdg. + 2D)
100 kΩ ...
100 MΩ
(AUTO)
±3 % 1200 V AC DC max. 10s
ISO-Ω
UN=
1000 V
0 ... 30 kΩ
0... 300 kΩ
0 ... 3 MΩ
0 ... 30 MΩ
0 ... 300 MΩ
0 ... 3 GΩ1)
0 ... 30 GΩ1)
10 Ω
100 Ω
1 Ω
10 kΩ
100 kΩ
10 MΩ
100 MΩ
±( 1.5% rdg. + 2D)
±( 1.5% rdg. + 2D)
±( 1.5% rdg. + 2D)
±( 1.5% rdg. + 2D)
±( 1.5% rdg. + 2D)
±( 3.0% rdg. + 2D)
±(20.0 % rdg. + 2D)
100 kΩ ...
100 MΩ
(AUTO)
±4% 1200 V AC DC max. 10s
Ω0 ... 3 Ω, analog
0 ... 30 Ω, dig. 5) 0.05 Ω
0.01 Ω
Þ3)
±(1.5% rdg. + 5D 0.2 Ω ... 4.0 Ω±(10%+2D) 0.315 A dauernd
6 ... 9.5 V 0.01 V ±(3.0% rdg. + 2D) 6 ... 9.5% —— —