Extech Instruments 380942 User manual

User’s 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
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.
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.
Yes
No

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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 3rd time returns the meter to normal operation.
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.

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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.

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 polarity
Current sensor Hall effect sensor type
Overload indication Left blinking digit
DCA zero adjust One touch zero key
Display rate 2 readings/second (20 readings/second for bargraph)
Battery Two 1.5V AA batteries
Operating conditions -10oC to 50oC (4oF to 122oF); < 85% Relative Humidity
Storage conditions -20oC to 60oC (- 4oF to 140oF); < 75% Relative Humidity
Altitude Operate at less than 2000 meters (for indoor use only)
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 Range Resolution Accuracy Overload
protect
CDA04Am1Am0004DC Current
30A 10mA
± (2.0% + 3d)
100A DC
50/60Hz 40 to 100Hz
400mA 0.1mA ±(1.5% + 5d) ±(2.0% + 5d) 40A AC
50/60Hz 40 to 1kHz
4000mA 1mA ±(2.5% + 5d) ±(3.0% + 5d) 40A AC
AC Current
(True RMS)
30A 10mA ±(2.0% + 5d) ±(2.5% + 5d) 100A AC
DC Voltage 400V 0.1V ± (1.0% + 2d) 1000V DC
50/60Hz 40 to 1kHzAC Voltage
(True RMS) 400V 0.1V ±(1.5% + 4d) ±(2.0% + 5d) 800V AC
Specification Notes
•AC Voltage and Current Crest Factor: < 3
•AC / DC Voltage Input Impedance: 10MΩ
Copyright ©2011 Extech Instruments Corporation (a FLIR company)
All rights reserved including the right of reproduction in whole or in part in any form.
www.extech.com
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