Extech 380940 True RMS AC/DC Mini Power Clamp Meter

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The compact Extech 380940 is a 400A mini True RMS AC/DC power clamp meter with a small diameter jaw designed to reach in small areas while providing power calculations up to 240kW. With the added convenience of instant watt readings — a feature normally reserved for full-size meters — this mini power clamp is useful for essential troubleshooting tasks in plant maintenance, electrical, HVAC, and telecom work, as well as residential electrical repairs, energy audits, fleet maintenance and marine electrics repair.


  • 400A AC/DC current readings
  • 240kW AC/DC power readings
  • True RMS AC measurements
  • Data hold, Min/Max and zero modes
  • Compact 23mm jaw opening

Authorised Australian Distributor

CE   UL   CAT II   1 Year


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Extech 380940

Whether you are checking amp draws on commercial electrical circuit or troubleshooting relays on vehicle air conditioning systems, the go-anywhere Extech 380940’s 23mm jaw opening is compact enough to fit in tight locations like engine bays. The useful data hold function freezes the display while the Min/Max function tracks and displays minimum and maximum values — useful for blind measurements and start-up draw. The zero function makes it easy to perform relative measurements. CAT II-rated, this meter is compact and easy to hold, and the 4-digit (4,000-count) readout is easy to read. Also, the 40 segment bargraph simulates an analog display, better illustrating swings in readings. In addition to power, current and voltage, the meter also measures frequency.

True RMS Compensates for Distortion from Electronic Devices

It can be very difficult to make accurate current and voltage readings in industrial and commercial applications when electronic devices are present. Fluorescent lights, motor drives, computer power supplies, and other electronic systems can distort the AC waveform, making it hard for averaging meters to get an accurate read. True RMS uses a more advanced formula to adjust for this kind of distortion.


General Specifications
Display 3-3/4 (4000 count) Digit LCD with 40 segment bargraph
Functions Watts, ACA, DCA, ACV, DCV, Frequency
Polarity “-“ 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)
Display rate 2 readings/second (20 readings/second for bargraph)
Auto Power Off 30 minutes after power ON
Battery Two 1.5V AA batteries
Operating temp. -10 v C to 50 ° C
Operating Humidity < 85% RH
Power consumption Approximately 10mA DC
Weight 190g including battery
Dimensions 183 x 63.6 x 35.6mm (HWD)
Jaw opening 23mm
Standards IEC 1010 Category III 300V, Category II 600V



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