The 20 series is a group of professional Fluke multimeters for electricians and electronics technicians working in tough, hazardous environments. They are the sturdiest multimeters on the market today and come with a great deal of protection, both electrically and mechanically. Although they are quite pricey, you get what you pay for at this end of the spectrum and if you’re working in mines and explosive environments, there’s little room for compromise.
We compare the three in the series here, detailing specs, features and usage. Check out the chart (below) for a visual overview.
27II: Average RMS heavy duty DMM
28II: True RMS heavy duty DMM
28II Ex: True RMS intrinsically safe multimeter
Common attributes:
- Tough case
- IP67 rating – dustproof / watertight
- Drop tested – 10ft
- High end input protection
- Auto / manual ranging
- Auto hold
- MIN/MAX-Average and Peak hold modes
- Backlit screen and glow buttons
- Analog bar graph
- Same size
- User-friendly
- Category: CAT-IV to 600V, CAT-III to 1000V
- Made in USA
Fluke 27II
This is the lower model of the 20 Series. A super-sturdy multimeter with most measurement ranges, it includes micro-amps and capacitance. It is an average responding RMS meter, so you won’t be able to measure non-linear AC signals accurately. Accurate and fast nonetheless, it is just as sturdy as the others and has the same level of input protection. Read full review…
Fluke 28II
This version is everything the 27 is, plus it comes with a higher level of accuracy on voltage and current and also features a temperature range. It is a True RMS DMM, too, so is good for accurately measuring AC variable speed drive outputs. The 28 also has a higher resolution screen – to 20,000-count. Read full review…
Fluke 28II Ex
The Ex version is significantly more expensive than the other two, but is classed as an intrinsically safe multimeter that stands up to Zone 1 and 2 hazardous environments. This can be employed in the chemical and mining industries, where a potential explosive environment would not suit the others. It is extra sturdy again, with a well engineered case and circuit board, making it both watertight and spark proof. Read full review…
Differences between the Fluke 27II, 28II and 28II Ex
| MODEL | 27II | 28II | 28II Ex |
|---|---|---|---|
| BASIC FEATURES | |||
| Digits | 3 5/6 | 4 1/2 | 4 1/2 |
| True RMS | - | ✓ | ✓ |
| Auto/Manual Ranging | ✓ | ✓ | ✓ |
| Battery | AA x2 | AA x2 | AAA x3 |
| Holster | ✓ | ✓ | ✓ |
| RANGES (MAX) |
|||
| Voltage AC / DC | 1000V | 1000V | 1000V |
| Current AC / DC | 10A (20A, 30s) | 10A (20A, 30s) | 10A (20A, 30s) |
| Micro-amps | ✓ | ✓ | ✓ |
| Milliamps | ✓ | ✓ | ✓ |
| DC V Accuracy | ±(0.2%+4) | ±(0.05%+1) | ±(0.05%+1) |
| Resistance | 50MΩ | 50MΩ | 50MΩ |
| Capacitance | 9,999µF | 9,999µF | 9,999µF |
| Frequency | 200kHz | 200kHz | 200kHz |
| Continuity (beep) | ✓ | ✓ | ✓ |
| Diode Test | ✓ | ✓ | ✓ |
| Temperature | - | ✓ | ✓ |
| MODES |
|||
| Min/Max Recording | ✓ | ✓ | ✓ |
| AutoHOLD | ✓ | ✓ | ✓ |
| Auto Power-Off | ✓ | ✓ | ✓ |
| DISPLAY |
|||
| Count | 6000 | 20000 | 20000 |
| Backlit | ✓ | ✓ | ✓ |
| Bar Graph | ✓ | ✓ | ✓ |
| SAFETY |
|||
| CAT-III Rating | 1000V | 1000V | 1000V |
| CAT-IV Rating | 600V | 600V | 600V |
| IP Rating | IP67 | IP67 | IP67 |
Conclusion
In the comparison of the Fluke 20 Series, it is fairly easy to decide between the three. If you want something that is watertight to diagnose faults in general electrical/electronic systems, and don’t need to measure temperature or AC variable drive units, the basic 27II is all you’d need. For more accuracy, higher resolution, non-linear AC signal measurement, and a temperature range, consider the 28II. For the most hazardous of environments, the 28II Ex is king.
All three have exceptional build quality and input protection and are made in the USA.
Hanging strap: TPAK magnetic hanging straps are very useful and it is best to pick up one of these to go with these multimeters as they are so heavy.
