Megger MTB7671, MTB7672 User Manual
M
MTB7671/2
Test box
User Guide
G Safety warnings
Safety Warnings and Precautions must be read and
understood before the instrument is used. They must be
observed during use.
Only use the MTB7671/2 when both polarity indicator
LEDs are lit.
The MTB7671/2 is protected by an integral RCD plug which
MUST NOT be removed from the tester.
The interlock protected 13 A socket should only be used with
double insulated RCD and Loop testers.
The instrument should not be used if any part of it is damaged.
Replacement fuses must be of the correct type and rating. Failure
to fit the correctly rated fuse may result in a safety hazard.
Only shrouded test leads should be used when measuring the
230 V a.c. mains supply
Users of this equipment and/or their employers are reminded that Health and
Safety Legislation requires them to carry out valid risk assessments of all electrical
work so as to identify potential sources of electrical danger and risk of electrical
injury such as inadvertent short circuits
CAT II - Measurement category II: Equipment connected between the
electrical outlets and the user’s equipment.
CAT III - Measurement category III: Equipment connected between the
distribution panel and the electrical outlets.
CAT IV - Measurement category IV: Equipment connected between the origin
of the low-voltage mains supply and the distribution panel.
NOTE
THE INSTRUMENT MUST ONLY BE USED BY SUITABLY
TRAINED AND COMPETENT PERSONS.
Symbols used on the instrument:
F Caution: risk of electric shock
G Caution: refer to accompanying notes
t Equipment protected throughout by Double Insulation (Class II)
c Equipment complies with relevant EU Directives
Equipment complies with ‘C tick’ requirements
Do not dispose of in the normal waste stream
Interlock cover
AC out supply
Fuse
Fuse
RCD and loop
test supply
socket
Continuity and
insulation test
select switch
Continuity
and insulation
connection
sockets
Supply
check
indicators
RCD and loop
test select switch
MTB7671/2
LOOP
+10Ω
OPERATION
The MTB7671/2 is intended for use with double insulated test
instruments only.
The MTB7671/2 has a combined earth and neutral which stops
it from tripping RCD protected circuits. To prevent the danger of
electric shock the MTB7671/2 is protected by a RCD plug and uses
a safety interlock for all live circuit tests.
1. SWITCHING ON
To switch on the MTB7671/2, plug the unit into the 230 V 50 Hz
mains supply using the integral RCD plug and depress the button
on the top of this plug and release, this will switch the plug on.
The bars on the plug should show red to indicate the unit is powered and the supply LEDs on the MTB7671/2 will be on.
To test the RCD plug, lightly press the button on the top (‘Test’
button). The red indicator bars should disappear and the supply
LEDs on the MTB7671/2 go out.
2. SUPPLY POLARITY CHECK
2.1 Supply Pass
The supply polarity check section on the MTB7671/2 should be on,
showing 2 green LEDs.
Do not use the test box unless both of these LEDs are lit.
NOTE: The polarity check will not detect if neutral and earth are
reversed.
3. AC Voltage output
The unit provides connection to the input mains supply to provide
a voltmeter check. The status of this supply is indicated by the
[230 V AC] LED. If this is not lit then the protection fuse has blown
and will need to be replaced.
Connect the tester to the voltage output terminals.
✍- Record the reading on the record card.
4. TESTING A CONTINUITY TESTER
Connect the tester to the continuity and insulation connection sockets in the orange and red section of the test box.
Warning: Do not apply more than 250 mA.
4.1 Current Test
Set the continuity and insulation test select switch to [I TEST] and
perform a continuity test. If the test instrument delivers more than
200 mA the [I TEST] pass LED will light.
✍- Record the reading on the record card.
4.2 Voltage Test
Set the continuity and insulation test select switch to [V TEST] and
perform a continuity test.
If the open circuit voltage from the tester is between 4 V and 24 V dc
the [V TEST] pass LED will light.
NOTE: The MFT1700 will require the buzzer to be turned on during
this test.
✍- Record the reading on the record card.
NOTE: If in either of the tests listed above the LEDs fail to light, the
test instrument under test should be returned for a full calibration.
4.3 0.5 Ω Test
Set the continuity and insulation test select switch to [0.5 Ω] and
perform a continuity check. This connects a resistor between the test
sockets of 0.5 Ω +/-3%. The tester should indicate a measured value
of 0.5 Ω (+/- operational errors including the tester’s accuracy).
✍ - Record the reading on the record card.
4.4 5.0 Ω Test
Set the continuity and insulation test select switch to [5 Ω] and
perform a continuity check. This connects a resistor between the test
sockets of 5 Ω +/-3%. The tester should indicate a measured value of
5 Ω (+/- operational errors including the test instrument’s accuracy).
✍ - Record the reading on the record card.
4.5 If an instrument fails the above tests, refer to note 5.6 for reverse
polarity instruments.
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