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Extech MA640 True RMS AC/DC 600A Clamp Meter with Non-Contact Voltage Detector

by Extech
4.5 out of 5 stars 15 customer reviews
| 4 answered questions

List Price: $159.99
Price: $126.39 & FREE Shipping. Details
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AC/DC
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  • Built-in non-contact Voltage detector with LED alert
  • 1.5" (40mm) jaw size for conductors up to 500MCM
  • 6000 count, backlit LCD display
  • Relative Mode for Capacitance Zero and Offset Adjustment
  • ata Hold and MIN/MAX, Auto Power Off
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Frequently Bought Together

  • Extech MA640 True RMS AC/DC 600A Clamp Meter with Non-Contact Voltage Detector
  • +
  • Extech 480172 AC Line Splitter
  • +
  • Extech TL809 Electronic Test Lead Kit
Total price: $159.35
Buy the selected items together

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Style: AC/DC

Product Description

Style: AC/DC

600A True RMS AC/DC Clamp Meter + NCV

The right-sized Extech MA640 600A True RMS autoranging AC/DC clamp meter offers plant maintenance techs, electrical troubleshooters, and DIYers a test instrument that delivers a high level of performance and value. In addition to a host of advanced multimeter and current measurement capabilities, it also features a built-in, non-contact voltage (NCV) detector.

Ergonomic & Versatile

The affordable clamp meter is compact and easy to hold. Whether you are performing amp readings in a heavy-duty industrial setting or doing commercial electrical work, the 600A rating and ample 1.5 inches (40mm) jaw opening can accommodate most jobs, swallowing conductors up to 750 MCM. The large, illuminated, dual display is useful in poorly lit job sites, and the 4-digit (6,000 count) readout is complemented by a bargraph display to simulate an analog display. You can operate the meter with one hand, having a thumb-dial selector that is ergonomically placed off the side of the meter. The heart of the MA640 is an advanced digital multimeter. You can select auto- or manual-ranging and measurement functions cover all types of troubleshooting over and above noninvasive current probe measurements: voltage, resistance, capacitance, frequency, duty cycle, diode and continuity tests. Even measure temperature with the supplied Type K bead wire probe. Users can also select one of several one-button functions: press HOLD to freeze a reading on the LCD; MAX/MIN tracks and displays maximum and minimum values (useful for blind measurements); and REL activates Relative mode for "zeroing out" the meter, useful for improving the accuracy of DC current measurements.

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. One important safety tool that is built in to the MA640 is a non-contact voltage (NCV) detector, which quickly detects the presence of voltage on live wires and alerts users with a red LED indicator. The MA640 measures 9.1 x 3 x 1.5 inches (HxWxD) and comes with test leads, 9-volt battery, carrying case, user manual, and manufacturer's one-year limited warranty on parts and labor. NIST certification is also available.


MA640 Features At-a-Glance
  • 600 amp AC/DC clamp meter
  • True RMS, Autoranging
  • Built-in NCV detector
  • Hold, maximum/minimum, relative data functions
  • Thermocouple temperature

Product Information

Style:AC/DC

Technical Details

Part Number MA640
Item Weight 9.9 ounces
Product Dimensions 9.5 x 5.2 x 2.4 inches
Item model number MA640
Batteries 1 9V batteries required. (included)
Style AC/DC
Item Package Quantity 1
Batteries Included? Yes
Batteries Required? Yes
Warranty Description 1 Year

Additional Information

ASIN B003N3UO9I
Customer Reviews
4.5 out of 5 stars 15 customer reviews

4.5 out of 5 stars
Best Sellers Rank #80,692 in Home Improvements (See top 100)
#59 in Industrial & Scientific > Test, Measure & Inspect > Electrical Testing > Current Testers > Clamp Meters
Shipping Weight 1.4 pounds (View shipping rates and policies)
Domestic Shipping This item is also available for shipping to select countries outside the U.S.
International Shipping This item can be shipped to select countries outside of the U.S. Learn More
Date First Available August 10, 2009

Warranty & Support

Manufacturer’s warranty can be requested from customer service. Click here to make a request to customer service.

Customer Reviews

Top Customer Reviews

Style Name: AC/DC Verified Purchase
The meter is very easy to operate one handed. The function select thumb wheel is much easier to operate than the selector on my Extech EX470. All of the buttons are reachable with your thumb. The focus is on the clamp meter so 4 selector positions are dedicated to the 2 AC and DC clamp amperage ranges. The thermocouple ("temp") setting gets its own position while all of the other functions are packed into two positions on the wheel: One for the ohmmeter, diode tester, capacitance meter and continuity tester, and one for the AC/DC voltmeter and frequency counter/duty cycle. The default modes are ohmmeter and DC volts. The additional functions are cycled with the "mode" button. Although this is a general purpose meter, one of the non-clamp type meters offers quicker access to functions like the cap meter. The non-contact voltage detector is always available in any mode.

The max/min feature is handy for making "blind" measurements since the unit will hold the maximum and minimum measured values taken while it is enabled. This allows you to reach into a corner with the clamp meter (or the probes) and take a reading without contorting to see the display. It doesn't work with auto-ranging, though, so be sure to select a range manually first or you may find max says 0L (overflow).

The non-contact voltmeter flickers constantly in any mode, becoming solid when the tip of the clamp is near an AC voltage. It is definitely possible to distinguish the random flickering from a solid signal, but the flickering makes it tedious to use to trace wires in walls, where a sharper on/off indication would be helpful.

The ohmmeter and voltmeter have the same slow, confusing auto-ranging as my Extech EX470.
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Style Name: AC/DC Verified Purchase
I've spent years getting by with only probe meters but kept finding a need for a clamp meter. I was looking for a true RMS meter and settled on this one. I've used it many times since buying it and it works very well. Not much to add regarding the details that other reviewers haven't already covered. For measuring current of household devices, make sure you get an Extech 480172 AC Line Splitter or similar device. Extech products have been good for me.
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Style Name: AC/DC Verified Purchase
I like the fact that it takes true RMS voltage reading, but the values I get when taking DC ampere are way off. For example, sometimes I get 5A when in reality it is less than 1A. I can't really recommend this product for the clamp / ampere readings, but everything else works fine.
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Style Name: AC/DC Verified Purchase
OK, this is the second ExTech meter I have purchased in the last month and I have to say this one does almost everything the Extech EX505 CAT IV-600V True RMS Industrial MultiMeter with Waterproof (IP67). Amazon had the best price on all of them and with Prime shipping they were here in a day or two. If I had purchased this first, it would most likely be all I needed for Home Remodeling, and Automotive uses. I spend my evenings as a novice electrical guy in my home and helping friends and with automotive modification. I would say over the years I have gotten proficient with electricity but know when to call in the experts. KNOW your limitations.

Pros
Size, compact, and ergonically designed. Sits nicely in your hand.
Well made, soliod feel --Rugged
Accuracy - vvery accurate from my perspective, comprable to higher end meters.
True RMS - In todays world, should have this capability
NCV
Dial in "activity" knob - well placed for eveffortless one handed operation - GREAT feel to the knob as you trnasition it from one setting to another.
True DC capability with no "in my head conversions"
Test Leads - Better made than my 505s leads. Much better quality with lengthy wires- feel like silicone
Carry Case, keeps everything organized

Cons:
No CAT IV - but I have my 505 for CAT IV
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Style Name: AC Verified Purchase
I purchased this unit from Grainger for use at work. No issues so far and I love all the features you get with it for the price. Only thing I with it had was a way to measure DC amps. I love the noncontact voltage detector, the RMS ampmeter, the Hz meter, and I love the thermocouple sensor.

I have honestly not checked its accuracy so I can't speak to that. But for what I use it for it seems accurate enough.

I work in the food industry so that comes in very handy. Loved it so much I bought it from Amazon for ~$30 cheaper than grainger. I have already recommended it to a fellow engineer and would recommend it again.
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Style Name: AC
This meter is good a little slow but no big deal.

My problem is the default setting for voltage is DC. I have to hit the mode button to get it to switch to. AC. In my experienced opinion it should be AC as default.

Read as accurate as my Fluke.

I do the the microfaret reader for checking capacitors.
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By AB on December 26, 2013
Style Name: AC Verified Purchase
I've used this meter for a while now. It does the job. it takes a couple of seconds to give the right reading, but it's ok. It's the right meter for the right price. It has everything I look for in a meter, even a temperature reading and it's the right size (Fits well in my hand). The voltage detector does not sound when near a power source, but sometimes that's a blessing, specially when the meter is close to a source and you're trying to check the voltage. I have another multimeter, but ever since I got this, it's the one I use most of the time.
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Extech MA640 True RMS AC/DC 600A Clamp Meter with Non-Contact Voltage Detector
This item: Extech MA640 True RMS AC/DC 600A Clamp Meter with Non-Contact Voltage Detector
Price: $126.39
Ships from and sold by Amazon.com
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