Unit UT528 User manual

P/N:110401109985X

Overview - UT528/528AU
UT528/528AU from.
UT528/528AU Main Unit
UT528/528AU

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Earth Nulling Block 1 x
＊
Neck strap 1 x
＊
IEC Lead 1 x
＊
Safety Information
Warnings - Please be aware of the following warnings.
●Before using the unit and test leads inspect both items. Do not use the unit
and test leads if they are damaged or the case is broken or damaged as this
could result in electrical shock.
●Replace the battery as soon as the battery indicator “ ”appears. Low
battery levels may produce inaccurate readings.
●Do not use or store the unit in high temperature, humid, flammable or
electromagnetic environments as damage and incorrect readings may result.
●If the tester requires repair or replacement please contact your local service
center.
Declaration of Conformity
Uni-T manufactures this product and declares that this product conforms to the

UT528/528AU
2013
2010

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8.Warning Symbol
9.Unit Error
10.Readings and Cable Results
11.Leakage Current
12.Double Insulated / Class II Test
13.Class I Test

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Class I Test Button + Zero/Null Selection
Class II Test Button + 250V/500V
Insulation
Selection
IEC / Cable Test Button +30m Long Lead Selection
Earth Probe Mains / IEC testing

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Front Panel Operation
1: Press + button to Power ON / Power OFF.
2: Press button when testing a CLASS I Appliance.
3: Press button when testing a CLASS II Appliance.
4: Press button when performing Cord / Extension Lead testing.
Advance Features
5. Press and hold the buttons to activate the 250V/500V and
0.1Ω/0.2Ω/0.3Ω earth continuity Pass/Fail Values setup.
+

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Before Testing - Zero the Earth Bond Test Lead!
Plug the earth probe into the rear of the unit and connect it to the earth nulling
adapter. Plug the earth nulling adapter into the front panel earth socket to
complete the circuit.
Press and hold the button for 5 seconds to zero the earth bond reading
using the earth bond lead and the nulling adapter together in the front test socket.
This will null the earth reading of the test lead and “GOOD” will be displayed once
complete. It is good practice to do this once prior to carrying out testing.
Auto Switch Off
The unit will automatically switch off after approximately 2 minutes if no buttons
are pressed.
Testing a Class 1 Appliance
Plug the appliance into the UT528/528AU panel main socket. Plug the earth test lead into
the socket on the UT528/528AU end panel. Connect the earth crocodile clip to an

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exposed metal part on the appliance as shown in Diagram 3.
1. Earth / Protective Conductor Test
Press the Class 1 test button to start the test. The earth resistance test will
begin.

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LOAD”. Press the button to proceed to the insulation test.
If this is not detected the unit will display a flashing symbol and also “LO
If the earth resistance meas ured is greater than the selected PASS limit for
earth bond (0.1Ω/0.2Ω/0.3Ω), the meter will display “×Earth Cont”, which is a
FAIL. If this occurs, re-check the connections between the pin of the plug to the
bodywork of the appliance and that the crocodile clip is attached to clean earthed
metalwork on the appliance (try attaching the clip to analternative piece of
metalwork). If all connections are OK the appliance earth connection may be
faulty.
The PASS limit for the earth bond test can be set to 0.1Ω, 0.2Ω or 0.3Ω for a
Class 1 appliance. (See page 17.)
If the reading is less than the selected PASS limit,the meter will display “√ Earth
Cont”, which is a PASS.
The unit will then automatically attempt to proceed to the insulation test. If it
detects that the appliance’s power switch is in the ON position it will carry out the
insulation test automatically.

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2. Insulation Resistance Test
Before the unit carries out the insulation test it will attempt to check that the
connected appliance’s power switch is in the ON position.
If it detects that the appliance switch is in the ON position it will automatically
carry out the insulation test.
Note: most electronic appliances will have electronic ON/OFF switches
and even though they are switched on the “Check Connections” message
will still appear.
If the measured resistance is greater than 1MΩ, the meter will display “√
Insulation” as a PASS rating.
If the insulation of the appliance is less than 1MΩ, it will display “× Insulation”
as a FAIL rating.
Leakage Test
3. After the unit has completed the insulation test it will automatically proceed to
the leakage test.

Sub Leak”
Sub Leak” as a
UT528/528AU
UT528/528AU
T

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Class 2 Pre-Check
If the unit detects that the appliance appears to be Class 1 as it detects an
earth connection (possibly as a result of a connected earth clip) it will display
a flashing symbol and you will be prevented from carrying out the Class
2 test. Test the appliance instead using the Class 1 test.
Insulation Resistance Test – Class 2 Appliance
Before the unit carries out the insulation test the unit will attempt to check to

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see if the appliance is in the ON position.
If it detects that the appliance switch is in the OFF position it will wait and
display a flashing symbol.
If you are sure that the appliance is switched ON press the button again
to start the test.
Note: most electronic appliances will have electronic ON/OFF switches
and even though they are switched on the flashing will still appear.
If the measured resistance is greater than 2MΩ, the meter will display “√
Insulation” as a PASS rating.
If the insulation of the appliance is less than 2MΩ, it will display “× Insulation”
as a FAIL rating.

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Leakage Test
5. After the unit has completed the insulation test it will automatically proceed to
the leakage test.If the measured leakage is less than 5mA, the meter will display
“√ Sub Leak” as a PASS rating.If greater than 5mA, it will display “× Sub Leak” as
a FAIL rating.
Class 2 FE
The FE stands for Functional Earth and the test is carried out using only the
centre Class ll button on the unit.
Plug the appliance under test into the mains socket on the front panel of the
unit and connect the earth test probe from the unit to an exposed metal part
on the appliance under test. If the unit detects an earth path then the display
"CL2 FE" ( if it does not detect an FE it will not display this message and will
carry on with a normal Class ll test )
Final Result - Class 2
After the above tests are completed, the meter will indicate whether the
appliance has Passed or Failed the Class 2test.
Testing an IEC Lead / Extension Lead / Cord Test
Plug the mains lead under test into the socket and the front panel mains socket
on the unit as shown in Diagram 5.

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To Start the Cord Test Press
1. Earth Bond Test
The unit will carry out an earth bond test in the same manner as a Class 1
appliance. The Pass mark for this test is less than the setup value(0.1,0.2,0.3Ω).
2. Insulation Test
The unit will then carry out an insulation test as previously discussed in the
manual. The PASS Mark for this test is 2 MΩ.

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Note: when testing Surge Protected Extension Leads this test may fail.
This is normal and a result of circuitry within the surge protection device.
3. Polarity Test
The polarity test is the final test to be carried out and will check that the cord
or extension is wired correctly. It will check for open circuit, short circuit or
Line / Neutral reversal.
If the Polarity is correct then the meter will display “LN√, LE √, NE√ PASS”.
If the Polarity test detects a fault, the meter will display “FAIL” and which
polarity is fault.
4. Overall Result
After the above measurements are completed, the meter will indicate
whether the measured appliance is compliant with the requirements of
cord testing with “PASS” or “FAIL”
Testing a Surge Protected Extension Lead or Appliance
When you press and hold the + buttons for 1 sec the tester will go

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into setup mode which can set up the 250V /500V test voltage and
button to save and turn back.
The insulation test voltage reduces from 500V to 250V to allow for the testing
of surge protected appliances and leads.
Checking a Mains Power Supply
The unit comes complete with a built in soket tester which will check to ensure
Pass /Fail value and the button to change test voltage,and the
Note: Each insulation test carried out will be the setup values. If you want
to change this setup mode, you need to re-set up the values again.
0.1Ω/0.2Ω/0.3Ω earth continuity Pass /Fail value, the button to change

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that the socket is wired correctly.
Connect an IEC lead to the mains socket and plug this into the back of the meter
as shown in Diagram 6.
1）If the Live and Neutral in the socket wiring are reversed or there is a fault with
the protective earth connection this is indicated as “LN√, LE×, NE×, FAIL”.
2）If there is a fault with the neutral connection this is indicated as “LN×, LE√,
NE×, FAIL”.
3）If the mains socket wiring is correct the display will show “LN√,LE√, NE√,
PASS”.

0.1/0.2/0.3 ohm
N/A N/A
N/A
Earth Continuity
Pass Limit& Accuracy
Test Current
Test Voltage
200mA minimum
5V nominal
±(5%+2)
±(5%+2)
±(5%+2)
Insulation Resistance
Pass Limit & Accuracy
Test Voltage
Test Current
Test Current
Default: 250V, Selectable: 500V
40Vrms,50Hz AC
>1mA 250k
<2mA 1k
<5mA 2k
Leakage Current
Accuracy
Test Voltage
Test Current
Factory Default PASS/Fail Limits
Earth Continuity
Insulation Resistance
Leakage
Class I Class II Cord
UT528 UT528AU UT528 UT528AU UT528 UT528AU
1.0Mohms
5mA
1.0 Mohms 1.0 Mohms 2.0 Mohms 2.0 Mohms
5mA
1 ohm0.2 ohm
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