RoadTest: Fluke 381 Clamp Meter
Author: WarrenW
Creation date:
Evaluation Type: Independent Products
Did you receive all parts the manufacturer stated would be included in the package?: True
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Detailed Review:
Fluke 381 Remote Display Clamp Meter Review
First Impressions
Well after waiting to get my hands on the meter, it finally turned up. I excitedly opened the packaging and was impressed with the weight of the unit. It feels SOLID and is no lightweight at 350gm! Like all good techo's I did not read the manual but dived right in head first and removed the battery isolation strips. The meter comes supplied with a total of 5 AAA alkaline batteries. My first thought was"I better get some batteries just in case".
It appears there is no electrical contact between the display and the meter body, implying that the batteries in the display are supplying current all the time and may go into a standby low power mode. There is what appears to be an infrared window in the meter body and display body, perhaps this is how it communicates when the display is fitted. I guess I WILL need to read that manual after all. By the way the manual looks like a small novel! It does contain seven languages though.
Packaging consists of the manual, a warranty card (valid for the US only - all others register online), several addendums to the manual, a statement of calibration (not a certificate), the I-Flex lead, 2 normal meter leads and probes, 2 slip on alligator clips for the meter leads and it's all housed in a sturdy padded soft carry case.
Reading the manual raised some interesting points. One of the things noted was that the radio link between the meter and display would normally be off when the display is docked, however it mentions that in some cases the radio may remain on when it is docked and the meter is turned off. No mention of how this may occur however to overcome this they recommend removal of the batteries. I guess this is why I would want to carry spare batteries, there are independent low battery indicators for both the meter and the display. The meter will auto power down after 20 minutes if there are no pushes of the buttons or activation of the rotary switch. Given that in some applications you may wish to monitor min/max values over a period that is longer than this, Fluke have disabled the auto shutoff during min/max/avg operation allowing a logging ability to be utilised.
Wireless range to the remote display is stated as a maximum of 10 meters, however as with any radio application this range can be affected by surrounding equipment etc.
The meter has a neat little indicator for detection of hazardous voltages, when these are detected the hazard light will illuminate.
Motor inrush can be measured and when activated the display waits until a current measurement is detected and then samples for 0.1 sec taking 400 samples.
Using the Meter.
As a user of my trusty Fluke 77 meter, I was quite impressed with the specs as the 381 is almost identical in every respect. In fact it exceeds the 77 with it's CAT ratings and the only thing I would comment on that limits it as a complete replacement for my now aging stalwart was the resistance range. The maximum range peaks at 60K ohm which limits it for some applications. Given that the meter is aimed at electricians rather than electronics techs, this is quite reasonable.
Certainly the addition of the high current measurement, max/min/avg function, back lit display, inrush measurement and frequency, you sure do get a lot of meter for your money.
Remote display operation was a breeze. Setup the meter and simply undock the display and take it with you to where you need to monitor the meter from . On the display you can control the backlight, min/max/avg function and the hold function. This allows for some operator input at the display without having to return to the meter.
The I-Flex current probe is selected independent of the internal jaw clamp range on the selector switch. Installing the I-Flex"rope' could not be easier, simply unlock the flying end by a twist of the holder and wrap it around the item to be measured, taking into account the location of conductor/s within the loop to maintain accuracy. Frequency can also be measured with the I-Flex adapter allowing monitoring of larger cabling installations.
Summary
Would I outlay the cash to buy this meter, you bet I would! The remote display is the outstanding feature I would say that sets this meter apart from most clamp meters. The flexibility it offers the operator is outstanding. Imagine trying to measure inrush current into a motor but the motor start switch is located elsewhere on the machine, the normal solution would be to have another person turn it on with you monitoring the meter. Now you do not need that additional person, setup the meter and do it yourself with the remote display.
Overall the specs of this meter are superb with only the resistance range limits being the only thing keeping me from retiring my Fluke 77 meter. It is a robust feeling unit and time will tell how well the batteries last, until then I am keeping a spare set in the carry bag with the meter.
UPDATE 23-9-2011
After several months of testing under varying conditions, I am still running on the same set of batteries. This is probably because the meter does sit for a while between uses, however having read some other info onnthe remote display, other people have claimed it chews through batteries when not in use. I can say quite confidently IT DOES NOT. The meter have been used with and without the backlight over a total of approaching 20hours of run time.
The reason behind the 9 out of 10 rating for the product performing to my expectations was probably due to my skewed expectations at the time. I was hoping it would totally replace my Fluke 77, however as we all know (me too now!) the 77 is geared towards an electronics environment whereas the 381 is aimed firmly at industrail electricians. The current range resolution is quite low but when you are measuring 1000+ amps whats 0.1A? Where I need to measure low currents - out come the 77.
All in all a great meter and with the flexibilty to allow remote display a highly recommended product.
Go buy one - you will not regret it.
