One of Fluke’s most durable multimeters is essentially an upgrade of the hugely popular 87V. A general purpose meter, it is especially adept at operating in harsh industrial environments. Its IP67 rating ensures that it is both dustproof and waterproof and it has Fluke’s rugged build quality and excellent input protection.
The Fluke 28II has also inherited the 87’s speed and accuracy, with quick auto-ranging and an impressive scope on its many ranges – it can measure up to 20 amps of AC and DC current, for example. Its CAT IV rating can have it testing the service side of three phase systems and it is good in a variety of other fields, including automotive, electronics and plant maintenance.
- IP67 dustproof / watertight
- True-RMS AC voltage and current
- Auto / manual ranging
- AC/DC voltage to 1000V
- AC/DC current to 10A (20A for 30s)
- AC voltage bandwidth (15Hz to 20kHz)
- Category rating: 1000V CATIII, 600V CATIV
- Capacitance to 10,000μF
- Built in thermometer
- Min/Max, average recording
- Hi res, 20000-count display
- Long battery life (800 hours)
- Glowing buttons
- Limited lifetime warranty
- Size: 7.8″ (198mm) x 3.9″ (99mm) x 2.5″ (63.5mm)
- Weight: 1.54lb (698g)
- Test leads (TL75)
- Three AA batteries
- Alligator clips
- Thermocouple temp probe
In-depth Review of the Fluke 28II
The 28 is part of the 20 Series of Fluke multimeters, which are built to high spec and with durable exteriors. The 27II is as tough, though doesn’t come with True RMS accuracy. This is essential for those testing AC voltage and current on variable speed drives that have non-linear signals.
In fact, the 28II has an extended AC voltage frequency bandwidth (15Hz to 20kHz), which makes it especially useful for testing variable speed drive systems. In addition is a low-pass filter for blocking out higher frequencies, plus you can also better test sensitive electronics with its high impedance mode.
Voltage ranges go up to 1000V, and current up to 10A on both AC and DC amps. Current can also be tested up to 20A for short periods (up to 30s). In addition is a DC millivolts range, while capacitance goes down into the nano-farads range.
The Fluke 28II can also work in freezing temperatures (down to 5°F / -15°C) – and lower temperatures again for shorter bursts – as well as measure temperature with the included type-K thermocouple. It can naturally handle high humidity, too, and has been drop tested from 10ft (3m).
The screen on the 28II is impressive, with a high resolution setting up to 20,000 counts. Large digits, buttons and a prominent dial selector allow it to be operated and read in inclement environments while donning gloves and safety gear. The screen is also backlit and even the buttons glow in the dark.
Among the other functions are a relative mode, to negate test lead resistance, a min/max mode for picking up low and high values automatically (such as temperature), and a smoothing mode to flatten out quickly changing signals.
|Max RANGE||Best ACCURACY|
|DC voltage||to 1000V||±(0.05%+1)|
|AC voltage||to 1000V||±(0.7%+2)|
|DC current||10A (max: 20A for 30s)||±(0.2%+2)|
|AC current||10A (max: 20A for 30s)||±(1%+2)|
|DC micro-amps||600μA / 6000μA||±(0.2%+4)|
|AC micro-amps||600μA / 6000μA||±(1%+2)|
|Capacitance||1nF / 9,999µF||±(1%+2)|
|Temperature||-328°F / -200°C to 1994°F / 1090°C||±1%|
|Diode test||to 2V|
Note: ±(0.05%+1): where ‘+1’ = +1 count / digit
Barring the 28II Ex, this is the toughest multimeter in Fluke’s arsenal and, as such, the build quality is excellent with a military-grade spec. Not only is the Fluke 28 II waterproof and dustproof (to IP67), it withstands shock and vibration and works just as well in highly humid environments.
It has Fluke’s trademark yellow rubber holster, while inside the case are a tongue and groove arrangement and an O ring to keep out the elements. The buttons are also rugged and it is both mine approved (MSHA) and has a good electrical safety rating. A secure cover gives access to the batteries, with a separate cover for the fuses.
The Fluke 28II has the same display as the 87V. It is dual count, with 6000-count and 20000-count easily selectable. The 6000-count setting will be fine for most general purpose jobs and refreshes faster than the 20000-count, which is useful if you need higher resolution on a given test, such as low resistance or millivolts. Capacitance and frequency don’t work on the Hi Res mode.
In addition is a very handy, fast-update bar graph that quickly picks up the changing values of erratic signals, refreshing itself 40 times a second. The display is backlit, with low and high brightness settings, and the glow-in-the-dark buttons are a handy upgrade from the 80 series.
Labels: the 28II is as simple to understand and operate as most other Flukes, with an uncluttered dial selector and clear markings.
Function and Performance
As one of the top of the range Fluke multimeters, the 28II performs well, with good response times, excellent accuracy and an amazing battery life. Although just the three AA batteries, they last a whopping 800 hours with standard use (i.e. not overuse of the backlight).
The uncomplicated dial selector switch has just seven range positions, with separate AC voltage, DC voltage, and DC millivolts ranges. A select button changes between AC and DC current ranges, plus there’s a low-pass filter on AC voltage. A slight drawback is the diode tester, which only puts out 2V, so you wouldn’t be able to successfully test all types of LED for instance.
Select (yellow) button: selects extra functions on a given range position
MIN/MAX: see the lowest/highest values (includes peak min/max)
RANGE: selects manual ranges and switches between auto and manual ranging
AutoHOLD: automatically finds the highest value
Hi Res / Backlight: selects the dual displays / turns on backlight
Continuity icon: enables/disables the beeper on resistance setting
REL: relative function for comparing readings and zeroing leads
Hz / %: frequency / duty cycle
There are several useful features and diagnostic functions on the 28II, such as an auto power-off (which can be disabled), a smoothing mode, high impedance mode, and a calibration mode. You can also center the bar graph for relative checks in analog view.
The four jack socket inputs are logically laid out and watertight. Both current inputs are fused. The main (voltage) terminal also includes the temperature measuring circuit, with the thermocouple adapter plugged across it and the common input.
Protection and Safety
This multimeter is built like a brick. The case is solid and waterproof, such that it can stand up to immersion in water to a depth of 1m for 30 minutes. It has also been drop tested to 3m and the circuitry is also well protected.
To see just how tough it is, take a look at Dave Jone’s (eevblog) video:
Most significantly, the Fluke 28II is IP67-rated, meaning it is dustproof as well as watertight. This is ideal for those working in hazardous environments, such as food production plants where water is a constant factor. Foundries and other hot and dusty environments will also suit this multimeter.
Electrically, it has excellent input protection and incorporates isolation slots and blast shields. The two HRC fuses for the amperage circuits (11A, 440mA) are rated to 1000V (to earth), and it can withstand spikes to 8kV. It is category rated to level CAT-III (@ 1000V) and CAT-IV (@ 600V), while also conforming to ANSI safety standards.
Input warning: the jack socket input circuitry features an optical warning system, whereby incorrectly plugged leads will set off an audible and visual warning. The condition of the fuses can be checked in-situ by using the red probe lead (plugged into the main terminal) on resistance and testing the A and mA/µA sockets.
Pros and Cons
Fluke 28II PROS
- Solid and very rugged
- IP67 dustproof/watertight
- Withstands high/low temperatures
- Fast and accurate
- Sharp, Hi Res display
- Excellent functionality
- AA batteries
- Exceptional battery life
- Separate battery/fuse compartments
- Includes Alligator clips
- Test leads could be better
- Quiet continuity buzzer
- Hanger doesn’t come as standard
- Diode test only 2V
We have detailed one of the toughest, most rugged and durable multimeters on the market today in this Fluke 28II review. This brick of a device overtakes the already solid 87V to create an almost indestructible test meter. It has all the functionality and finesse of the 87 and can be used in harsh environments.
In addition, the Fluke 28II is easy to use, although it might be a bit bulky for general purpose day to day use. The optional magnetic hanger is worth getting for this meter especially as it is heavy.
Alternatives: if you don’t need to measure temperature or variable AC drive outputs, and need to save money, the 27II is equally as good durability wise. Even more rugged is the Fluke 28 II Ex, while the Fluke 87V is the other obvious alternative, though is minus the extra protection and waterproofing.