UNI-T UT525, UT526 Operating Manual

Operating Manual

UT525/526

Electrical Testers

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UT525/526 Operating Manual

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Contents

Item Page

I. Safety Precautions

II. Features

III. Specications

IV. Front View of the Instrument

V. Function of Keys and Dial Plate

VI. Testing Preparation

VII. Earth Testing

VIII. RCD Testing

IX. Voltage Testing

X. Insulation Resistance Testing

XI. Replace Battery

XII. Maintenance

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UT525/526 Operating Manual

Overview

UT525/UT526 is a digital multi-functional electric testing instrument adopting
new design and integrating large scale analog integrated circuit, digital circuit
and microprocessor chips, which can mainly test parameters of residual current
device (RCD), earth, insulation resistance, DCV and ACV; with features of full
functions, high accuracy, stable performance, easy and reliable operation, it
is available to test RCD, insulation and earth of electric equipments. UT525/
UT526 is the ideal selection for repairing, maintaining and testing RCD of all
electric equipments.

I. Safety Precautions

This instrument was designed, manufactured and tested according to
IEC61010 safety standard (Safety Requirements for Electrical Equipment).
This Instructions describe the warnings and safety rules which ensure the safe
operation and safe state of the instrument, which the user must follow. Please
read following instructions before using.

Warning

● Please read and understood the Instructions before using.

● Please follow the requirements of the Instructions, keep the
Instructions well for further reference at any time.

● During testing, incorrect operation will cause accident and
instrument damage.

Sign on the instrument tell the user that some operations should be
made according to relative requirements of the Instructions to ensure safety
operation of the instrument.

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UT525/526 Operating Manual

It means under some conditions, the operation may cause
serious or fatal damages may be caused.
Warning It means taking care to keep away from electric shock.
It means avoiding instrument damage and gain accurate

testing.

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UT525/526 Operating Manual

Note

Danger

Danger

● Do not test circuit with AC440V/DC440V or above.

● Do not test in the place with inammable conditions.

● Do not operate the instrument if the surface of the instrument is wet or the

hand is wet.

● During testing, do not touch the conductive part of the testing pen.

● Do not open the battery cover during testing.

● During testing insulation and RCD, do not touch the circuit to be tested.

Warning

● When there is anything unusual to the instrument, such as the instrument
is damaged or the metal is exposed, please do not use it.

● Operate carefully under the voltage over 33Vrms, 46.7Vacrms or 70Vdc,
electric shock may be caused under such kind of voltage during operating.

● After completing high resistance testing, the charge storage of the circuit
to be tested must be released.

● Do not replace battery if the instrument is in place with humidity.

● Make sure the all testing wires are connected with the testing ports rmly.

● Before opening cover of the battery, please make sure the instrument is

turned off.

Note

● Before testing resistance, the circuit to be tested must be discharged
completely and separated from the power circuit absolutely.

● If the testing pen or adapter is damaged and needs to be replaced,
please replace with testing pen or adapter with the same model and

electric specications.

● When the battery sign ( ) shows that the battery is used up, please do
not use the instrument any more. If the instrument won’t be used for a long
time, please take out the battery and then keep the instrument well.

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● Do not put or use the instrument in the place with high temperature, high

humidity, inammable or explosive matters and high electromagnetic eld.

● Do not clean the cover of the instrument with wet cloth of detergent, do not
use abrasives or solvent.

● When the instrument is wet, please make it dry and then put it in the
proper place.

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UT525/526 Operating Manual

II. Features

Danger of electric shock may happen

The instrument has double-insulation or reinforced insulation

DC

AC

Earth

● Designed and manufactured strictly according to IEC61010 safety
standard, the instrument meets with Over Voltage Standard (CATIII600V)
and safety standard of Class II Pollution.

● Auto discharge function.

● Red warning light.

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UT525/526 Operating Manual

III. Specications

Error limit: ±(a% reading + digits), one year of warranty period
Environment temperature: 23±5℃
Environment humidity: 45-75%RH

UT525/UT526 RCD testing indexes

RCD testing current 10mA 30mA 100mA 300mA
Applied voltage Voltage: 220V±10%, frequency: 45Hz-65Hz
Accuracy tolerance

RCD testing current accuracy tolerance with AC (220V±2): (0+10%)

Testing time
range when
switch of
RCD is off
Accuracy tolerance ±(5%+2)

(10mA) range: 0-2,000mS
(30mA) range: 0-500mS
(100mA) range: 0-300mS
(300mA) range: 0-300mS

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UT525/526 Operating Manual

UT525 earth testing indexes

Rated voltage About 5.0V

Test range 0.01Ω-200Ω
Test current ＞200mA for 0.00Ω-2.00Ω
Accuracy tolerance 0.01Ω-200Ω: ±(2%+5)

UT526 earth testing indexes

Rated voltage About 5.0V

Test range 0.01Ω-2,000Ω
Test current ＞200mA within 0.00Ω-2.00Ω
Accuracy tolerance 0.01Ω-2,000Ω: ±(2%+5)

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UT525/526 Operating Manual

UT525 insulation resistance testing indexes

Rated voltage 100V 250V 500V

Test range 0.05MΩ-200MΩ

Open circuit voltage DC 100V±10% DC 250V±10% DC 500V±10%

Rated test current 100KΩ load 250KΩ load 500KΩ load

Short circuit ＜1.8mA

Accuracy tolerance 0.05MΩ-200MΩ: ±(5%+5)

0.9mA-1.1mA

0.9mA-1.1mA

0.9mA-1.1mA

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UT525/526 Operating Manual

UT526 insulation resistance testing indexes

Rated voltage 250V 500V 1,000V

Test range 0.05MΩ-200MΩ 0.05MΩ-300MΩ 0.05MΩ-500MΩ

Open circuit voltage DC 250V±10% DC 500V±10% DC 1,000V±10%

Rated test current 500KΩ load 1MΩ load 250KΩ load

Short circuit ＜1.8mA

Accuracy tolerance 0.05MΩ-500MΩ: ±(5%+5)

0.9mA-1.1mA 0.9mA-1.1mA

0.9mA-1.1mA

UT525/UT526 voltage testing indexes

DCV ACV
Test range ±0-±440V 0-440 (50/60Hz), just for reference to
that less than 10V
Resolution 1V

Accuracy tolerance ±(2%+3)

UT525/UT526 frequency testing indexes

Test range 20Hz-100Hz
Resolution 1Hz
Accuracy tolerance Just for reference

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● Display: LCD display, max reading: 9999

● Low battery voltage warning:

● Over limit indication: “OL”

● Auto range function

● Unit display: can display function, electric unit signs

● Work conditions: 0℃-40℃/ 85%RH or less

● Storage condition: -20℃-60℃/90%RH or less

● Dimensions: 150mm(L)×100mm(W)×71mm(D)

● Current consumption: about 50mA (1,000V output) (about 10mA in general

condition)

● Accessories: testing wire, alkaline battery (1.5V, AA)×6, Instructions,
carrying bag

● Weight: 0.7kg (including batteries)

● Power: alkaline battery (1.5V, AA)×6

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UT525/526 Operating Manual

IV. Front View of the Instrument (see Picture 1)

1. L: jack of live wire terminal for RCD testing and positive terminal for voltage
testing

2. E: jack of earth for RCD testing

3. N: jack of null wire terminal for RCD testing and input negative terminal for
voltage testing

4. LINE: jack of high voltage output for insulation resistance testing

5. LCD

6. RCD current setup key and voltage testing switch key

7. RCD angles switch key and return-to-zero key

8. Test button

9. Dial plate

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Picture 1

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V. Function of Keys and Dial Plate

1. I/VOLT is RCD current testing range selection and voltage testing switch key;

2. ANG/ZERO is RCD testing angle switch key and return-to-zero key before
starting earth testing;

3. TEST is test key;

4. When dial plate points to Continuly, enter earth test;

5. When dial plate points to RCD/V, enter RCD testing and AC and DC voltage
testing;

6. When dial plate points to UT525 output voltage: 100V/250V/500V or UT526
output voltage: 250V/500V/1,000V (select the demanded output voltage)
respectively, enter insulation resistance testing;

VI. Testing Preparation

When turning on the instrument, if the battery sign on the left of LCD shows
low voltage, it means the battery is almost used up and needs to be replaced.
Low voltage display sign Voltage of battery
7V or less

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UT525/526 Operating Manual

VII. Earth Testing (see Picture 2 for the connection diagram )

Connect the object to be tested with the instrument according to the diagram,
after that make the dial plate point to Continuly, and then press TEST key to
start earth test.

Note

1. To keep the accuracy of test, return-to-zero operation must be made (return­ to-zero operation by pen: in state of earthing, make the two pens in reliable
short circuit state, after that press TEST key, and then press ANG/ZERO
return-to-zero key, the resistance of the pens will be clear to “0”, and the
LCD displays ZERO.

2. Do not test live object.

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Picture 2

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VIII. RCD Testing (see Picture 3 for the connection diagram)

Make the dial plate point to RCD/V and press I/VOLT key to set up test current
(test current: 10mA\30mA\100mA\300mA) to start RCD testing.

Connection Method:
Connect the red, green and blue testing wires of three-wire plug with the red
(L), green (E) and blue (N) ports respectively, and then insert the three-wire
plug into the 220V civil jack and press TEST key.

Note

1. During testing RCD, the earth terminal of power jack must be grounded
reliably.

2. During testing RCD, make sure that connection of L (live wire), N (null wire)
and E (earth wire) of power jack are connected rightly.

3. This testing is made under high voltage, pay attention to personnel safety

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Picture 3

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IX Voltage Testing (see Picture 4 for the connection diagram)

Make the dial plate point to RCD/V and the long press I/VOLT key to switch to
AC, DC voltage testing state:

Connection method 1:
(1) Insert red testing wire into “L” input port, and black testing wire into “N”
input port.
(2) After connecting red, black alligator clips or probes to the circuit to be

tested rmly, press TEST key, the system will judge the AC or DC voltage

automatically, and the voltage and frequency will be displayed on LCD.

Connection method 2:
Connect the red, green and blue testing wires of three-wire plug to the red (L),
green (E) and blue (N) ports of the instrument respectively, after that insert the
plug into the jack of the circuit to be tested and press TEST key, the system
will judge the AC or DC voltage automatically, and the voltage and frequency
will be displayed on LCD.

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UT525/526 Operating Manual

Note

1. Do not input voltage over 440V or 440Vrms. It is possible to display higher
voltage, but the instrument may be damaged.

2. During testing high voltage, especially avoid electric shock.

3. After completing all the testing, cut the connection between testing wires
and the circuit tested, and dismantle the testing wires from input terminal
of the instrument.

4. When the battery cover is open, do not test.

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Picture 4

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X Insulation Resistance Testing (see picture 5 for the connection

diagram)

Note

1. Before testing, make sure that the circuit to be tested is uncharged, do not
test the insulation of charged equipment or live circuit.

2. When the battery cover is open, do not test.

3. Do not make the two pens short circuit state under high voltage input and
do not test the insulation resistance after outputting high voltage.

Press to make the dial plate point to UT525 (100V/250V/500V) or UT526
(250V/500V/1,000V)

1. Before testing insulation resistance, the circuit to be tested must be
discharged completely and separated from the power circuit absolutely.

2. Insert the red testing wire into “LINE” input terminal, and black testing wire
into “N” input terminal.

3. Connect the red, black alligator clips to the circuit to be tested, and the high
voltage is outputted from LINE terminal.

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UT525/526 Operating Manual

Continuous Testing Operation
Select one test voltage with dial plate (the optional voltages of UT525:
100V/250V/500V; the optional voltages of UT526: 250V/500V/1,000V) and
press TEST key which is in self-locking state to make continuous testing and
output insulation resistance testing voltage, and the test light become red. After
completing testing, press TEST key to unlock to stop testing.

Note

1. Before testing, make sure that the circuit to be tested is uncharged, do not
test the insulation of charged equipment or live circuit.

2. After completing testing, do not touch the circuit with hand, the stored
electric capacity may cause electric shock.

3. Cut the connection between testing wires and the circuit tested, do not
touch them with hand until the voltage is released completely.

4. When the battery cover is open, do not test.

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Picture 5

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UT525/526 Operating Manual

XI. Replace Battery (see Picture 6)

Note

1. Do not use old and new batteries at the same time.

2. Pay attention to the polarity during replacing battery.

Danger

1. To avoid potential electric shock, move the lead from the instrument before
replacing battery.

2. When the battery cover is open, do not test

3. When sign “ ” is displayed on LCD, it means the battery needs to be
replaced, please operate as following:

1) Turn off the power (namely make the dial plate point to OFF), and move
testing wires away.

2) Loosen screw on the battery cover, and move away the battery cover,
and then replace the 6 batteries.

3) After replacing the batteries, make sure that the screw is tightened

rmly.

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Picture 6

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XII. Maintenance

Clear the shell

● Wipe the surface with soft wet cloth or sponge.

● To avoid instrument damage, do not dip the instrument into water.

● When the instrument is wet, make it dry and then store.

● When the instrument needs to be checked or repaired, please let

qualied professional maintenance man to repair or send it to the

designated maintenance point.

The content is subject to change without prior notice