UNI-T UT253A, UT253B Operating Manual

P/N:110401103625
DATE:2018.06.26
REV.3

Contents

TITLE PAGE
Warnings 2
I. Introduction 4
II. Model Comparison 5
III. Electrical Symbols 6
IV. Technical Specifications 7
V. Meter Description 10
VI. Operating Instructions 12

1. Power On/Off 12

2. Backlight Control 12

3. Data Hold and Save 12

4. Data Access and Exit 13

5. Data Transmission to PC 13

6. Data Delete 14

7. Leakage Current, Current and Voltage Measurements 14
VII. Battery Replacement 18
VIII. Packing List 19

1

Warning

Thank you for purchasing .
In order to use the product properly, please follow instructions
below:

2 3

s

UNIT large jaw leakage current clamp meter

Read user's manual carefully.
Strictly observe safety rules and notes mentioned in this manual.

I. Introduction

UNIT large jaw leakage current clamp meter, supported by latest CT and
digital integration technologies and coupled with large diameter clamp(80mm

80mm, able to enclose 80mm cable or 96mm 4mm flat steel ground
wire) and automation function, is professional tool for measuring leakage
current, current and voltage. It can simultaneously measure one-way leakage
current and three-way voltages and offer simultaneous display on the screen,
which all together allow users to operate easily and quickly. The meter is
widely used in electric power, communications, meteorology, railway, oil field,
construction, metrology, R&D institutes, mining, ect.

This kind of meter is designed with clamp iron core made with special alloy
and latest magnetic screening technology, which make it able to avoid
magnetic interference from outside and ensure high accuracy, stability and

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reliability all the year around. It contains RS232 interface that allows its
maximum storage of 200 sets of data to transfer into PC, thus facilitating
further operations such as on-line monitoring, history lookup, dynamic display,
history data recall, save and printing. Other functions such as backlight and
data hold together with those mentioned above turn the meter a necessary
tool for electrical safety testing.

II. Model Comparison

Model

UT253A

UT253B

Range

0.00mA 1200A 0.01mA 80mm 80mm

0.0mA 2000A 0.1mA 80mm 80mm

Resolution

Jaw Size

III. Electric Symbols

IV. Technical Specifications

Extreme danger! To avoid personal injury or accidents due to electric
shock, observe safety rules strictly.

Danger To avoid personal injury or accidents due to electric shock,
please follow safety regulations.

Warning Conform to safety notes, otherwise it may cause personal
injury or damage to the meter.

Dual insulation

Alternating Current AC

Direct Current DC

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Functions

Power

Measuring Mode

Jaw Size

Range

Resolution

Conductor Location

Data Save

RS232 Port

to measure leakage current, current and three-phase
AC voltage

6V DC(LR6 4 Alkaline dry battery,12 hours of battery
life)

Clamp-shape CT integral mode

80mm 80mm (Able to clamp 80mm conductor or
96mm 4mm flat steel ground line)

Current: AC 0.00mA 1200A; Voltage: AC 0.00V 600V

Current: AC 0.01mA; Voltage: AC 0.01V

Placed at the center of clamp jaw

Maximum 200 sets, indicated by FULL flash icon.

Yes, for data transmission to PC for further data analysis

Measuring Accuracy
(23 3 70%

RH, conductor located

at the center of jaw

Communication Line

Frequency

Function Switchover

Sample Rate

Circuit Voltage

Display Mode

Dimensions

Backlight

Data Hold

0.00mA 300A: 1.5% 3dgt

300A 1200A: 2% 3dgt

1200A 2000A: 3% 3dgt

0.00V 600V 1.5% 3dgt

RS232 type, 1.8 meters long

Self-identification between 50Hz and 60Hz

Automatic
about 2 times per second

To measure AC voltage below 600V

LCD 128dots 64dots
Display Zone: 43mm 29mm

( Long wide thick)275mm 145mm 40mm

Controlled by LIGHT button

Data maintained: Indicated by HOLD icon

Overload Display

Auto Power Off

Battery Voltage

Weight

Operating Current

Operating

Temperature/ Humidity

Storage

Temperature/ Humidity

Insulation Strength

Safety Standards

Followed

Out of range indicated by OL icon

Automatically 15minutes later after power on, to
conserve power energy

Low battery icon displays with battery voltage
below 5.2V, please change batteries.

The meter 1kg(battery and accessories included)

50mA consumed with backlight on; 25mA when
turning off backlight

-10 40 80%rh

-10 60 70%rh

AC 2kV/rms(Between iron core and housing)

IEC1010-1, IEC1010-2-032, Pollution Class 2, CAT (600V)

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V. Meter Description

1. Clamp Jaw

2. Function Buttons

3. LCD Display

4. Voltage Input Terminal

5. Jaw Opening Trigger

6. RS232 port (to transfer data to PC)

7. Screws (to connect upper and lower covers, 6pcs)

8. Battery Cover

9. Screw (to fix battery cover, 1pcs)

101112

VI. Operating Instructions

1. Power on/off
Press POWER button to power on, display LCD and enter into measuring
mode, repress to turn off the meter. The meter will automatically switch off
15 minutes later after power on. You should change the battery if dark LCD
appears after power on and may be caused by low battery voltage.
Under data save status, you need to press HOLD button to cancel the
operation before press POWER button to power off the meter.

2. Backlight Control
Use LIGHT button to control backlight, suitable for dark sites and at night.
The default is backlit status after power on.

3. Data Hold and Save
Under measuring mode, press HOLD button to maintain displayed data,
indicated by HOLD icon, and repress to cancel the operation. The meter

will automatically number current data at the time of saving, indicated by
group number such as SAVE NO. 001 . Maximum data storage is 200
sets and is achieved when FULL icon shows

4. Data Access and Exit
Under measuring mode, Press MENU to access data research with
indication of READ icon. You can start data research from R 001 ,
press Up button to increment by 1, down button to increment by 10
and MENU button to exit this status and return to measuring mode.

5. Data Transmission to PC
The accessory RS232 connection line is used for communication of the
meter with PC. With the meter power on and the software running, several
following operations such as history lookup, data recall, save, report sheet,
history printing can all be performed. The more data the meter saves,
more time it will take to read out. History data can be saved in Txt or Excel
format.

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6. Data Delete
Press CLEAR button to select data clearing option under data access
mode, then use Left or Right button to move the cursor for selecting
YES or NO , finally press MENU button to confirm the operation or
return to the measuring mode.

7. Leakage Current, Current and Voltage Measurements

Dangerous Voltage! To avoid personal injury or accidents in case of
electric shock, only trained and authorized staff is allowed to operate
and must strictly observe safety rules

Danger! To avoid any damage to the meter or personal injury in
case of electric shock do not measure voltage above 600V

Please Keep the jaw properly open or close when measuring
leakage current or current.

Try to place the conductor at the center of the jaw

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Please keep the jaw clean and regularly maintained after finishing
measurement.

Ensure correct wire connection to avoid short-circuit problem during
voltage measurement

Disconnect test leads with measured lines before pulling them out
of the meter in case of electric shock

Clamping live and wires is to measure leakage current of
electric instruments(2 wires needed)

Clamping the ground wire is to measure its leakage current (single
wire needed)

Clamping all three phases and four wires is to measure total
leakage current(four wires needed)

Clamping the main wire is to measure current of the main circuit
(single wire needed).

neutral

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Measuring Reference Figure:

Measuring Leakage
Current of Built-in
Cable

Measuring

Tank

Measuring Total
Leakage

Measuring Instrument
Leakage Current

Measuring Ground
Leakage Current

Measuring Current and

Voltage Phase Angles

16

Grounding Line

17

VII. Battery Replacement

VIII. Packing List

Warning !

To avoid potential risks do not measure when battery cover is not well

placed.

Please ensure right battery polarity, otherwise it will damage the meter.
Change batteries timely when low battery icon displays.
Take out batteries when not used for a long time.

1. Low battery icon displays with voltage lower than 5.2V, please change the
battery timely.

2. Press POWER button to switch off, loosen one screw on battery cover
and open it after confirming the meter is off, finally change with new
specified batteries and close the battery cover.

3. Press POWER button to switch on and check if batteries are
successfully replaced, if not, repeat the second step.

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The Meter

Carrying case

Data transmission software CD

RS232 exclusive communication line

Battery(LR6 Alkaline Dry Battery)

Giftbox/User's Manual/ Warranty Card/Certificate

1

1

1

1

1 set

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