Extech Instruments 380942 User manual

User Guide

Model 380942
True RMS AC/DC 30A Mini Clamp-on Meter

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Introduction

Congratulations on your purchase of the Extech Model 380942 DC/AC Clamp Meter. This meter is
shipped fully tested and calibrated and, with proper use, will provide years of reliable service.

Meter Description

1. Current sense jaw

2. Measurement Trigger

3. Function switch

4. Data HOLD key

5. MAX / MIN key

6. One-touch DCA ZERO key

7. LCD Display

8. Positive input terminal for Voltage

9. COM terminal

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Safety Symbols and Information

!

Caution ! Refer to the explanation in this Manual

Caution ! Risk of electric shock

Earth (Ground)

This meter has been designed to be safe in use, but the operator must use caution in its operation.
The rules listed below should be carefully followed for safe operation.

1. NEVER apply voltage or current to the meter that exceeds the specified maximum:

2. USE EXTREME CAUTION when working with high voltages.

3. DO NOT measure voltage if the voltage on the "COM" input jack exceeds 600V above earth
ground.

4. ALWAYS turn off the power and disconnect the test leads before opening the back to replace
the fuse or batteries.

5. NEVER operate the meter unless the back cover and the battery/fuse door are in place and
fastened securely.

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Operation

AC Current Measurements (True RMS)

WARNING: To avoid electric shock, disconnect the test leads from the meter before making current

measurements.

1) Set the Function switch to the 400mA, 4000mA, or 30A AC range.

2) Press the jaw trigger and clamp around, fully enclosing a single conductor.
Do not allow a gap between the two halves of the jaw. Refer to the diagram
at right for the correct way to enclose a single conductor.

3) Read the AC Current value on the LCD’s digital or bargraph display.

DC Current Measurements

WARNING: To avoid electric shock, disconnect the test leads from the meter before making current

measurements.

1) Set the Function switch to the mA or 30A DC range.

2) Press the DCA zero key to null the meter display.

3) Press the Trigger to open the current sense Jaw.

4) Fully enclose the conductor to be measured. Do not allow a gap between the two halves of the
jaw.

5) Read the DC Current value on the LCD’s digital or bargraph display.

AC Voltage Measurements (True RMS)

WARNING: To avoid electric shock or damage to the meter, do not make any voltage

measurements that exceed the maximum specified limits.

1) Set the Function switch to the 400V AC position.

2) Insert the test leads to the meter as follows: Red lead to “V” terminal; Black lead to the COM
input.

3) Connect the test leads to the circuit or device under test.

4) Read the AC Voltage value on the LCD’s digital or bargraph display.

Yes

No

DC Voltage Measurements

WARNING: To avoid electric shock or damage to the meter, do not make any voltage

measurements that exceed the maximum specified limits.

1) Set the Function switch to the 400V DC position.

2) Insert the test leads to the meter as follows: Red lead to “V” terminal; Black lead to the COM
input.

3) Connect the test leads to the circuit or device under test.

4) Read the DC Voltage value on the LCD’s digital or bargraph display.

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Advanced Features

Relative Measurements

1) Press the ZERO key. The displayed reading will zero and the word ZERO will appear on the
upper portion of the LCD.

2) All subsequent measurements will now be displayed with respect to the zeroed reading. For
example, if a 20A reading is zeroed and a 30A reading is subsequently measured, the LCD will
display 10A.

3) To return to normal operation, press and hold the ZERO key for 2 seconds until the word ZERO
switches off.

4) Note that Relative mode is not available if MIN/MAX mode is enabled.

Data Hold

To freeze the current reading on the LCD, press the Data Hold key. The word HOLD will appear on
the LCD while the meter is in the Data Hold mode. To release the Data Hold function and return the
meter to normal operation, press the Data Hold key again. The word HOLD will switch off.

MIN/MAX Readings

Pressing the MIN/MAX key allows the meter to display the highest and then the lowest readings
encountered. Press the MIN/MAX key once to view the minimum reading, press it again to view the
maximum reading. Note that the meter will only change its displayed reading when a measurement
is taken higher than the previous MAX or lower than the previous MIN readings. The HOLD display
icon (along with the MIN or MAX icon) will appear on the LCD in MIN/MAX mode. Pressing the
MIN/MAX key a 3

Auto Power Off

To extend battery life, the meter will auto power off after 30 minutes of operation. To resume
operation, either turn the meter OFF and then ON again, or press the HOLD button. To disable the
auto power off function, press down the “HOLD” key while turning the meter on.

rd

time returns the meter to normal operation.

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Maintenance

Battery Replacement

1) When the low battery symbol appears on the LCD the batteries must be replaced.

2) Turn the meter OFF and remove the rear battery compartment Phillips screw.

3) Lift off the battery compartment cover and replace the two 1.5V AA batteries.

4) Replace the compartment cover and secure the screw.

5)

You, as the end user, are legally bound (EU Battery ordinance) to return all used
batteries, disposal in the household garbage is prohibited! You can hand over your
used batteries / accumulators at collection points in your community or wherever batteries /
accumulators are sold!

Disposal: Follow the valid legal stipulations in respect of the disposal of the device at the
end of its lifecycle

Cleaning

Caution: Use only a dry cloth to clean the plastic case.

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Specifications

General Specifications

Display 3-3/4 digit (4000 count) LCD with 40 segment bargraph

Functions ACA, DCA, ACV, DCV

Polarity Minus sign ( - ) indicates negative polarit

Curre

nt sensor Hall effect sensor type

Overload indication Left blinking digit

DCA zero adjust One touch zero ke

Display

rate 2 readings/second (20 readings/second for bargraph)

Battery Two 1.5V AA bat

ating conditions -10

Oper

Storage conditio

Altitude

Power consumption Approximately 10mA DC

Weight 190g (6.2 oz.) including battery

Dimensions 183 x 63.6 x 35.6mm (7.2 x 2.5 x 1.4”) (H x W x D)

Jaw opening 23mm (0.9”)

Standards IEC 1010 Category III 300V, Category II 600V

Range Specifications

Function

DC Current 4000mA 1mA ± (2.0% + 3d) 40A DC

AC Current

(True RMS)

DC Voltage 400V 0.1V ± (1.0% + 2d) 1000V DC

AC Voltage

(True RMS)

ns -20

30A 10mA 100A DC

400mA 0.1mA ±(1.5% + 5d) ±(2.0% + 5d) 40A AC

4000mA 1mA ±(2.5% + 5d) ±(3.0% + 5d) 40A AC

30A 10mA ±(2.0% + 5d) ±(2.5% + 5d) 100A AC

400V 0.1V ±(1.5% + 4d) ±(2.0% + 5d) 800V AC

o

C to 50oC (4oF to 122oF); < 85% Relative Humidity

o

C to 60oC (- 4oF to 140oF); < 75% Relative Humidity

Operate at less than 2000 meters (for indoor use only)

Resolution Accuracy Overlo

Range

y

teries

50/60Hz 40 to 100Hz

50/60Hz 40 to 1kHz

50/60Hz 40 to 1kHz

y

protec

ad

t

Specification Notes

 AC Voltage and Current Crest Factor: < 3
 AC / DC Voltage Input Impedance: 10M

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