Cool Tools: FLUKE Handheld Digital Multimeter - Review

Table of contents

RoadTest: Cool Tools: FLUKE Handheld Digital Multimeter

Author: nermash

Creation date: 14 Aug 2018

Evaluation Type: Test Equipment

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?: Fluke 115, 87V, 287

What were the biggest problems encountered?: Correct placement of conductor in the specified target position.

Detailed Review:

First of all I would like to thank Fluke and Element14 for providing me with opportunity to test this interesting piece of test equipment.

By no means have I claimed to be an electrician, merely an electronics hobbyist and big fan of Fluke gear.

What inspired me to apply for this Roadtest was the pretty negative review of Fluke T6 and FieldSense functionality done by video blogger Ave.

Now, don't diss me Ave fanboys, I watch the guy often, but I feel that his area of expertise is more in a hydraulics and machinery field, rather than in electrical or electronics.

However, I had a strong feeling that a company with such industry respect and status would not have easily allowed itself to launch a substandard and unsafe product. This is why I applied.

Overview

Here is the family photo (I apologize for the glare)

T6 1000 is large electrical tester, well built and robust, with rotary knob easily handled and operated by one hand.

As you can see, all the meters basically agree with each other, T6 being maybe one count out, still within specified accuracy for ACV of ±1.5% +2 counts.

Test leads are not removable (though available as spare part assembly), and are placed on the back of the unit for storage. Unit is powered by 2 AA batteries, with 200-360 hrs of battery life.

Batteries are replaced by unscrewing the back cover, and unfortunately Fluke decided to use thread forming screw instead of one with metal insert. Thumbs down.

LCD is clear, well lit, and with two types of backlight: white one for normal operation and green for FieldSense functionality.

This is top of the line T6 1000 model, with 1000 V AC range and dual line LCD. It also has extended Ohms range to 100 kOhms and frequency measurement.

TESTING

As I mentioned, I am no electrician, so I decided to test some basic and relatively low power stuff.

Low power in terms of 220 VAC, that is.

FieldSense test::220 VAC through black wire, left hand on the ground contact, sitting on a chair.

FieldSense test::220 VAC through black wire, left hand on the ground contact, body connected to earth.

T6 is reading somewhat higher than actual voltage, and with proper grounded contact.

Still within specified accuracy range for FieldSense AC voltage ±3% +3 counts.

Alignment of wire on the target is critical to get a reading, you must place a wire exactly on the little notch above the red “V” symbol.

FieldSense test::Small universal motor running on 222 VAC, left hand on the ground contact, sitting on a chair.

According to my Fluke 115, this motor is drawing 215 mA of current. Specified accuracy for T6 AC current is ± 3% + 3 counts.

FieldSense test::Small universal motor running on 222 VAC, left hand on the ground contact, body connected to earth.

FieldSense test::60W incandescent bulb running on 222 VAC, left hand on the ground contact, sitting on a chair.

FieldSense test::60W incandescent bulb running on 222 VAC, left hand on the ground contact, body connected to earth.

FieldSense test::Frequency measurement on 222 VAC, left hand on the ground contact, sitting on a chair.

FieldSense test::Frequency measurement on 222 VAC, left hand on the ground contact, body connected to earth.

Mystery device on the ground contact

There has been a lot of controversy going on about the exposed ground contact on the back of the T6.

In order for FieldSense to work properly, you are supposes to touch this bare metal contact with your hand and have your body grounded.

This metal ground contact becomes active only when you place the black lead in its storage compartment on the back of the unit.

If you are using T6 as regular tester with both leads, then this ground contact on the back is not active!

With all this controversy, I had to try to figure out how it works and what could be inside?

Since there is infinite DC resistance between ground pad and black lead contact, I decided to employ some AC analysis, and use my trusty LCR Meter

LCR measurement, auto@100 HZ

LCR measurement, auto@1 kHz

LCR measurement, auto@10 kHz

LCR measurement, auto@100 kHz

From the measurements, it can be observed that this is not a purely capacitive coupling, since there is always a minimum of around 200 kOhms of resistance at higher frequencies, where capacitive reactance is going low due to high frequency.

My guess is that mystery ground device is an array of distributed capacitors and resistors components, with lump capacitance of 2 nF and min ESR of 200 kOhms.

This concurs with the videos and measurements taken by other esteemed video bloggers, showing an array of 5 SMD devices on a flex strip (probably capacitors, connected in series with carbon printed resistors), connecting the black lead to metal ground contact.

I also learned from other reviews and teardowns that the estimated breakdown voltage of this array is most likely around 1 kV AC, while the frontend input will protect up to 1.7 kV.

It is worth noticing that this device is sealed in plastic, so that any contamination from field work (moisture, dirt, oil,..) will not cause it break prematurely.

OTHER POINTS OF INTEREST

Further on, I tested all the usual suspects on a DMM:

Continuity buzzer: somewhat slow, and not latched. Not the Fluke finest work, but I guess adequate for electrical work

Ohms ranging speed: slowish for a mere 100 kOhm range, I measured about 2.5 sec from the moment open leads are closed to display showing 0.

DC Volts accuracy: No issues found, using my DC standard and Fluke 287 as reference meter

2.5 V DC

5V DC

7.5V DC

10 V DC

CONCLUSION

Well designed and robust, large, easy to use, reasonably accurate meter for electrical work.

Comes with some interesting new technology, to my knowledge this is the first meter ever that can measure voltage with a single point of galvanic contact.

There are some drawbacks:

* FieldSense is not a precise tool. It will give you some indication that can be used for quick and dirty measurement, or as a starting point for some further analysis.

* If you are industrial electrician, you very well likely have to wear insulation gloves and rubber booths as PP equipment. In that case, FieldSense will not work correctly or will not work at all.

* Trying to pull a wire from a cabinet to make it aligned in the fork might cause some connection issues up or down on the line.

DO I THINK IT IS SAFE TO USE WITH FIELDSENSE?

Yes, if you use it properly, i.e. NOT as a single pole tester, but using only the fork as contactless method of measurement. This is the only and proper way to use FieldSense functionality.

IF you use it with red lead sticking out and connected to live wire, and your hand acting as ground on the back of the unit, then you can expect to have a voltage of around 100-200V AC on that contact and couple of µA of  AC current.

You will probably not even feel it, but if a surge comes along of 3kV or more (not uncommon in an industrial high voltage and high energy environment), then you are exposing yourself to a very high risk of being electrocuted, since the tiny array of 5 SMD devices will be vaporized and arced over in a flash (pun intended).