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User Manual
Model 380943
High Resolution 60 Amp AC Clamp-on Meter
• 4000 Count Display with 10uA Resolution
• 20 reading per second bargraph
• Shielded transformer jaws
• Selectable filter circuit
• MAX/MIN, Relative, & Hold functions
• 1.2” (30mm) jaw diameter
Introduction
Thank you for selecting the Extech 380943 AC Clamp Meter. This device is ideal for
checking leakage, ground, and sheath current. This professional meter, with proper care,
will provide years of safe reliable service.
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Model 380943 Ver. 2.1 11/2002
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Specifications
General Specifications
Display 3-3/4 digit (4000 count) LCD with 40 segment bargraph
Functions ACA, ACV, Resistance, and Continuity
Polarity Minus sign ( - ) indicates negative polarity
Overload indication Left blinking digit
Relative Mode ZERO front panel key
Display rate 2 readings per second (20 readings per second for bargraph)
Battery Two 1.5V AA batteries
Operating conditions 40F to 1220F (-100C to 500C); < 85% Relative Humidity
Storage conditions - 40F to 1400F (-200C to 600C); < 75% Relative Humidity
Altitude Operate at less than 2000 meters (Indoor use only)
Power consumption Approximately 10mA DC
Weight 7 oz. (200g) including battery
Dimensions 8.3 x 2.4 x 1.4” (210 x 62 x 35.6mm) (HWD)
Jaw opening 1.2” (30mm)
Standards IEC 1010 Category III 300V, Category II 600V
Range Specifications
Range / Resolution Accuracy
50/60Hz
Accuracy
40Hz to 1Khz
Overload
Protection
AC Current
40.00mA ± (1.0% + 3 digits)
± (2.0% + 5 digits)
400.0mA
± (1.0% + 3 digits) ± (2.0% + 3 digits)
4.000A
± (1.0% + 3 digits) ± (2.0% + 3 digits)
40.00A
± (1.0% + 3 digits) ± (2.0% + 3 digits)
60.0A (0 to 50A)*
± (1.5% + 3 digits) ± (3.0% + 5 digits)
60.0A (50 to 60A)*
± (3.0% + 5 digits) ± (3.5% + 5 digits)
100A AC
AC Voltage
400.0V ± (1.5% + 2 digits) ± (2.0% + 4 digits) 800V AC
Resistance and Continuity
Range Accuracy Audible
Continuity
Overload
Protection
40.0 to 400.0Ω
± (1.5% + 2d)
Beeps < 38Ω
600V AC
Specification Notes
• Open Circuit Voltage: 0.4V
• AC Voltage Input Impedance: 10MΩ
• Accuracy specified at 25
o
C
* Displays over 60A are possible but the accuracy of such measurements is not specified
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Model 380943 Ver. 2.1 11/2002
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Meter Description
1. Current sensing jaws
2. Jaws opening trigger
3. Function switch
4. Data HOLD key
5. MAX / MIN key
6. ZERO (Relative) key
7. LCD Display
8. Frequency select slide switch
9. Positive input terminal for V and Ω
10. Negative (COM) input terminal
Safety Information
!
Caution ! Refer to the explanation in this Manual
Caution ! Risk of electric shock
Earth (Ground)
Double Insulation
This meter has been designed with safety in mind, but the operator must use caution. 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 meter to
replace the fuse or the batteries.
5. NEVER operate the meter unless the back cover and the battery/fuse door are in place
and fastened securely.
1 2 5 6 7 9
3 4 8 10
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Model 380943 Ver. 2.1 11/2002
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Operation
Using the Frequency Selector Switch
50/60Hz position (low pass filter)
Use the 50/60Hz position when measuring circuits with a frequency bandwidth of 50/60Hz.
Since the meter has superior frequency response, measurement results may include
higher frequencies and harmonics of the fundamental frequency. Putting this switch in the
50/60 position activates the meter’s low pass filter minimizing the affects of high frequency
noise. The filter’s cut-off frequency is 100Hz with 24dB/octave attenuation (approx.).
WIDE Position (for high frequencies)
Put the slide switch in the WIDE position if the circuit under test is a high frequency
generating device (up to 1KHz) such as an inverter, switching regulator, etc. To verify the
presence of a high frequency signal, take measurements in both switch positions. If the
readings are widely different, then a high frequency signal can be assumed present.
AC Current Measurements
Basic Current Measurement Procedure
WARNING: To avoid electric shock, disconnect the test leads from the meter before
making current measurements.
1. Set the Function switch to the desired current range.
2. Set the Frequency slide switch to the appropriate position (refer to the paragraph
above to determine which position to use).
3. Press the jaw trigger to open the clamp jaws and clamp around the conductor(s)
ensuring they’re fully enclosed by the clamp jaws.
4. Refer to the applications diagrams below for specific measurement configurations.
5. Read the ACA value on the LCD digits and the bargraph.
AC Current Applications
Load Current Measurments
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Leakage Current on Unbalanced Loads
Ground Conductor Leakage Single Phase 2-Wire Leakage
Three Phase 3-Wire Leakage Three Phase 4-Wire Leakage
AC 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 Voltage position.
2. Set the Frequency Slide Switch to the appropriate position (refer to the section “Using
the Frequency Slide Switch” earlier in this manual).
3. Insert the test leads to the meter as follows: Red lead to the red ‘V’ input terminal;
Black lead to the black COM input terminal.
4. Connect the test leads to the circuit or device under test (see diagram example below).
5. Read the ACV value on the meter’s display (LCD digits and bargraph).
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