UT278A - Mètre Uni-T - Free user manual and instructions

Product Type	Digital Clamp Meter
Brand	Uni-T
Model	UT278A
AC Current Range	0.01mA ~ 1000A
AC Voltage Range	0.1V ~ 600V
Resistance Range	0.1Ω ~ 40MΩ
Capacitance Range	0.1nF ~ 100μF
Frequency Range	10Hz ~ 10MHz
Display	Digital LCD with backlight
Data Hold	Yes
Auto Range	Yes
Safety Rating	CAT III 600V
Power Supply	9V battery (6F22)
Dimensions	225 × 70 × 40 mm
Weight	≈ 300 g (including battery)
Operating Temperature	0°C ~ 40°C
Storage Temperature	-10°C ~ 50°C
Humidity	< 80% (non-condensing)
Accessories Included	Test leads, carrying case, battery, manual
Jaw Opening	30 mm

Frequently Asked Questions - UT278A Uni-T

How do I measure AC current with the UT278A?

Set the rotary switch to the AC current range (A~). Clamp the jaw around a single conductor. Read the value on the LCD. Ensure the conductor is centered in the jaw for accuracy.

What type of battery does the UT278A use?

The UT278A uses a standard 9V battery (6F22). To replace, open the battery compartment at the back.

How do I check continuity?

Turn the dial to the continuity test position (usually a diode symbol or sound wave). Connect the test leads to the circuit. A continuous beep indicates low resistance (< 50Ω).

Can the UT278A measure DC current?

No, the UT278A is designed for AC current only. It measures AC leakage current from 0.01mA to 1000A.

What is the accuracy of the UT278A?

Accuracy varies by range. Typically, AC current: ±(1.5% + 5 digits), AC voltage: ±(1.0% + 3 digits). Refer to the manual for specific ranges.

How do I replace the fuse?

The UT278A has a replaceable fuse for the current input. Disconnect test leads, open the battery/fuse compartment, and replace with a 10A/250V fuse of the same type.

Why does the display show 'OL'?

'OL' stands for Overload. The measured value exceeds the selected range. Switch to a higher range or use Auto Range mode.

Can I measure voltage with the clamp?

Yes, you can measure AC voltage up to 600V by using the test leads. Insert the black lead into COM and red lead into VΩ terminal.

How do I clean and maintain the meter?

Clean the exterior with a dry, soft cloth. Do not use solvents. Keep the jaws clean and free of debris. Store in a dry place.

Is the UT278A safe for use near live circuits?

Yes, it is rated CAT III 600V, meaning it is safe for use on distribution-level circuits. Always follow safety precautions and use proper PPE.

USER MANUAL UT278A Uni-T

Display count		10000	10000 4 digits	LCD display
Jaw opening		28mm	28mm 32mm	32mm
Resistance measurement frequency	>1kHz			√	√
Single measurement time	1 second			√	√
Current limit alarm	1mA~499mA			√	√
Current measurement frequency	50Hz/60Hz			√	√
Auto power off		√	√
RS-232				√	√
Visual and audible alarm				√	√
Jamming signal recognition				√	√
Over-range display				√	√
Data storage		30 30 99 99

GENERAL CHARACTERISTICS

Power	1.5V battery (LR6) x 4
LCD size	47mm x 28.5mm
Product color	Red and grey
Product net weight	UT273/UT275: 1320g; UT276A/UT278A: 1160g
Product size	UT273/UT275: 293mm x 90mm x 66mm; UT276A/UT278A: 285mm x 85mm x 56mm
Standard accessories	Batteries, test ring, tool box
Standard individual packing	Gift box, English manual
Standard quantity per carton	UT273/UT275: 5pcs; UT276A/UT278A: 6pcs
Standard carton measurement	UT273/UT275: 510mm x 375mm x 320mm; UT276A/UT278A: 610mm x 375mm x 320mm
Standard carton gross weight	UT273/UT275: 15.2kg; UT276A/UT278A: 18kg
Optional accessories	UT276A/UT278A: RS-232 interface cable, PC software CD

UT278A

UT270 series can quickly and safely measure the grounding system without disconnecting circuit ground lines or the need of auxiliary electrodes. It can measure resistance from 0.01Ω with a resolution of 0.001Ω. UT275 can also measure leakage current up to 30A. These clamps' double insulation design makes them durable tools for outdoor work and effective in blocking interference signals from the environment.

● Resistance limit alarm
● Auto range
● Low battery indication
● Data hold (UT273/275)
● Data recall (UT273/275)
● LCD backlight (UT273/275)
● Auto calibration (UT273/275)