Review of Fluke 381 Clamp Meter

Table of contents

RoadTest: Fluke 381 Clamp Meter

Author: K5HJ

Creation date:

Evaluation Type: Independent Products

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?:

What were the biggest problems encountered?: Several coworkers keep asking to borrow it.

Detailed Review:

First, let me thank the folks at element14 and Fluke for giving me the opportunity to test this product.
My primary interest is in the entertainment lighting industry where you will find a variety of fairly high power lamps, LEDs, dimmers, and other control devices.  It is not unusual to see a small 3 to 4 foot tall rack controlling 115kW loads and some larger racks with 230kW connected.
Right out of the box I was impressed with the solid build quality and the nice carrying case with compartments for the test probes and the iFlex current probe.
Since most of my interest lies in testing around the factory and engineering department, I made a few tests that are common at our plant.  This photo shows one of our burn-in test areas for large dimmers.   I was able to locate the remote display at the control position which is about 30 feet from the test racks.  Here I am testing inrush current on some incandescent loads.
This inrush current feature is very useful.  Usually, for small to medium loads, we have to resort to an oscilloscope and current probe to do this.  Even worse is with large loads, hundreds of Amperes, a resistive shunt and isolated oscilloscope are used.  This can be inconvenient to set up and dangerous to perform.
I decided to give the iFlex probe a try.  Here are a couple of examples.  The first photo shows how one could measure the total current in multiple load strings where a clamp-on would not be practical.  The other shot is an example of running the probe through a tight bundle of wires and using two loops to be able to scale the current up where the load is fairly light.  This happens to be a 400W HID lamp with about 5 Amps of current being driven by a high frequency ballast.
With LED products, measurement of DC current is also common.  Here, I am looking at the DC feeds to some LED modules in a moving light fixture.  The boss won't let me reveal the actual current but it is a lot higher than you might expect.  (Did I say "high power LEDs?")  If you look at my element14 Avatar you might get a better idea what I'm talking about.
Although Fluke probably did not target the automotive industry with this product, I did try some tests measuring DC current on my Toyota Tacoma pickup truck.  Here you can se a remote measurement of the starting current.  I can see this as a valuable tool for testing and trouble shooting DC currents as well as AC.
As to the other features of this meter, I did some comparisons with my trusty Fluke 77 and another brand "true RMS" meter, measuring both AC and DC voltage as well as resistance.  All of these functions worked as expected.  Not a terribly impressive range of resistance measurement but it is more than adequate for its intended purpose.  The continuity beeper is handy for quick tests and circuit tracing.  The test leads are sturdy and the clips are well insulated and have a nice snug fit onto the probes.  The MIN, MAX and HOLD functions are nothing new but do come in handy and are to be expected with most modern meters.

The manual is a typical multi-lingual beast which I thumbed through to look at specifications but really did not need to operate the meter.  Nothing surprising here.


The 381 has an impressive feature set with the quality and performance I have come to expect from Fluke.  The remote display and iFlex current probe make everyday tasks more convenient and, more importantly, a lot safer.  This is the first time I have had a meter capable of measuring 2500A in my arsenal and this is a big plus.  I am sure we will be adding a few more of these to our equipment pool.

Please feel free to ask me any questions you might have.