What the Fluke 28 II Ex Intrinsically Safe Multimeter Does and Where It Applies

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The Fluke 28 II Ex intrinsically safe true RMS digital multimeter is a meter that Fluke markets as intrinsically safe for use in hazardous atmospheres. Its manufacturer pages list ATEX, IECEx, North American (NEC/CEC) and other Ex approvals, and they give voltage, current, resistance, frequency and capacitance ranges. This guide explains what an intrinsically safe meter is, what the 28 II Ex measures according to the two Fluke pages we opened, and where the sources leave questions open.

Quick answer

• The Fluke 28 II Ex is a true-RMS multimeter with Ex certifications listed for ATEX, IECEx, NEC/CEC and several other regions.
• The manufacturer pages list AC and DC voltage up to 1000 V, AC and DC current up to 10 A, and resistance up to 50 MΩ.
• The certification wording differs between the two Fluke regional pages, so check the marking on the meter and the certificate before you rely on a specific zone or class.

How we chose

The keyword names one specific model, so we opened the two Fluke product pages for the 28 II Ex: the Canadian English page and the UK English page. Both are manufacturer pages. We did not use search snippets, retailer prices or star ratings. Where the two pages give different wording, we say so in the body below rather than choosing one.

What intrinsic safety means

An intrinsically safe instrument is designed so that its electrical energy is kept low enough that it cannot ignite a specific flammable atmosphere under defined fault conditions. The Ex marking on the meter names the protection concept and the zone or division the meter is approved for. A meter that is intrinsically safe for one area may not be approved for another, so the marking is the first thing to read. The Fluke pages state that the approvals apply to the 28 II Ex specifically; a standard 28 II without the Ex marking is not described as intrinsically safe in these sources.

The Canadian page includes a note that Ex zones require reduced measurements. The page does not list which measurements are reduced in each zone, so do not assume the full specification applies inside a hazardous area. Follow the instruction manual and the site rules for the area where you work.

What the 28 II Ex measures

Both Fluke pages give the same core ranges. DC voltage runs from 0.1 mV to 1000 V with a stated accuracy of ±(0.05% + 1). AC voltage runs from 0.1 mV to 1000 V with ±(0.7% + 4). DC current is listed from 0.1 µA to 10 A, and AC current from 0.1 µA to 10 A with ±(1% + 2). Resistance runs from 0.1 Ω to 50 MΩ. Frequency is listed from 0.5 Hz to 199.99 kHz.

The UK page also lists capacitance from 10 nF to 9999 µF with ±(1% + 2), and a temperature range from -200 °C to +1090 °C. The Canadian page, as we read it, does not give those two rows in the same form, so treat capacitance and temperature as specifications the UK page states and confirm them on the current manual.

The meter is described as a true-RMS instrument. The Canadian page says it measures AC voltage and current accurately on nonlinear signals. This matters on variable-speed drives and other distorted waveforms, where an average-responding meter can read low. The page also describes a low-pass filter that is meant to give accurate voltage and frequency readings on variable-speed motor drives. The filter’s cut-off frequency is not given in the text we read.

For display, both pages describe a backlit LCD with 6000 counts, or 19,999 counts in a high-resolution mode. The meter has a peak capture function for transients down to 250 µs, according to the UK page.

Ex certifications

The Canadian page lists these approvals: ATEX as II 2G Ex ia IIC T4 Gb and I M1 Ex ia I Ma; IECEx as Ex ia IIC T4 Gb and Ex ia I Ma; and North American approvals for Class I, Division 1, Groups A to D. It also lists PCEC (China), Simtars (Australia), IEx (Brazil) and GOST R Ex. The UK page gives the same ATEX and IECEx marks. It lists the North American approval as Class I, Division 1, Groups A to D, T4, and also as Class I, Zone 1, AEx ia IIC T4.

The two pages do not agree on every North American detail. The Canadian page describes an NEC-500 entry with a 130 °C figure, while the UK page gives a T4 temperature class. We have not resolved this difference, and we do not use either figure as the marked rating. The approval label on your meter, and the Fluke certificate for your region, control.

Safety ratings and build

Both pages give the safety categories as CAT III 1000 V and CAT IV 600 V. The Canadian page describes an IP67 sealed case with IP6X dust protection. The UK page gives a three-year warranty and a 400-hour battery life on three AAA batteries. Those battery and warranty figures come from the manufacturer page for the region named, and they may change with the regional product.

Where this kind of meter fits

An intrinsically safe multimeter is for work where a standard meter could create an ignition source. Typical settings named in the Fluke text include hazardous process areas. Inside those areas the meter does not replace the site permit, gas testing or lockout process. The meter gives electrical readings; it does not decide whether a task is safe to start.

If your work is general electrical troubleshooting with no hazardous-area rules, the approvals on this model add cost you may not need. The sources do not compare the 28 II Ex with other meters on price or performance, so that choice has to be made on the work requirements, not on the page text.

Step-by-step: checking the meter before use

1. Read the Ex marking on the meter label and match it to the zone or division of your work area.
2. Check the battery condition and install three AAA batteries as the manual specifies.
3. Inspect the test leads and the probe tips for cracks or exposed metal before connecting.
4. Select the function and range for the measurement. The sources we opened do not state the ranging mode for this model, so confirm it on the manual.
5. Take the reading with the leads in the correct jacks, and follow the manual for probe placement.

This sequence follows general practice for handheld meters. The sources do not give a Fluke procedure for hazardous-area checks, so the site procedure and the manual take priority.

What we could not verify

• The two Fluke pages differ on the North American temperature class, and we could not confirm which figure applies to a given unit.
• The pages do not state which measurements are reduced inside each Ex zone.
• The low-pass filter’s cut-off frequency is not stated in the text we read.
• Neither page gives a full accuracy table for every frequency and mode, so the figures above are the ones shown on the pages.
• We could not check the current manual, which may differ from the product pages.

FAQ

Is the Fluke 28 II Ex the same as the standard 28 II?

No. The sources treat the Ex model as a separate product with its own intrinsic safety approvals. The Fluke pages we opened describe the Ex version and do not state that the standard model has the same approvals.

Can I use it in any hazardous area?

No. The meter lists approvals for specific zones and divisions. Check the marking against the area classification at your site.

What is the highest voltage it measures?

Both pages list DC and AC voltage up to 1000 V. The safety category ratings are CAT III 1000 V and CAT IV 600 V, so the category depends on the installation point.

Does it measure temperature?

The UK page lists a temperature range from -200 °C to +1090 °C. The Canadian page, as we read it, does not give the same row, so confirm this on the manual for your unit.

For related reading on this site, see our article on true-RMS clamp meters and our article on handheld digital multimeters.

Bottom line

Choose the 28 II Ex when the work area requires an intrinsically safe meter whose marking matches the zone. Read the marking first, then the manual for the reduced-measurement rules, and do not rely on a general specification in a hazardous area.

Sources

• Fluke, 28 II Ex intrinsically safe product page, Canada English: https://www.fluke.com/en-ca/product/intrinsically-safe/fluke-28-ii-ex (opened 2026-10-30)
• Fluke, 28 II Ex intrinsically safe product page, UK English: https://www.fluke.com/en-gb/product/intrinsically-safe/fluke-28-ii-ex (opened 2026-10-30)