How to spot counterfeit Fluke test equipment

Fluke is the most counterfeited brand in test and measurement. The fakes have improved to the point where a photograph is no longer enough to judge, and the risk is not just wasted money: a counterfeit meter carrying a CAT III 1000 V marking it cannot actually survive is a genuine safety hazard for whoever uses it.

Which models get faked

Counterfeiting follows volume. The models copied most often are the ones sold in the largest numbers and at price points where a fake still returns a healthy margin: the 15B and 17B (particularly the China-market versions), the 101, 106 and 107 pocket meters, the 117 electrician's meter, and increasingly the 87V.

High-value instruments are copied far less often. Nobody is building convincing fake 754 documenting calibrators or Ti480 thermal imagers, because the engineering cost is prohibitive and the buyer pool is too knowledgeable. If you are buying at the handheld end of the range, that is where your scrutiny belongs.

The physical checks that actually work

Start with the case. Genuine Fluke housings use a specific holster texture and a rubber overmould that is bonded rather than glued. Fakes often show a visible seam line where the overmould meets the case, or a rubber that feels tacky rather than dry.

Look at the rotary switch. On a genuine unit it moves with distinct, evenly weighted detents and no lateral play. Counterfeit switches feel loose, and the detents are often uneven across the range.

Check the input jacks. Fluke uses recessed shrouded jacks with a consistent gap between the shroud and the jack body. Fakes frequently get this dimension wrong, and standard Fluke test leads will either sit proud or wobble.

Read the display at an angle. Genuine LCDs have a wide viewing angle and even segment darkness. Fake displays wash out quickly off-axis and often show uneven segment contrast, particularly on the decimal points.

Serial numbers and firmware

Every genuine Fluke instrument has a serial number that encodes its manufacturing location and date. Counterfeiters copy real serial numbers, so a valid-looking serial proves nothing on its own — but a serial that does not match the model's known format is a definitive fail.

Firmware behaviour is harder to fake than a label. On a genuine 87V, holding the appropriate button during power-on runs a segment test that lights every display element in a specific sequence. Fakes usually implement something approximate, or skip it entirely.

Where a model supports it, check the reported firmware version against what Fluke published for that serial range. A mismatch is a strong signal.

Open the case if you can

The internal build is where fakes are least convincing. Genuine Fluke instruments use a heavy fibreglass PCB, generously sized high-rupture-capacity fuses, and a conformal coating over the input protection circuitry.

Counterfeits typically use a thin single-sided board, a glass fuse where an HRC fuse should be, and visibly absent input protection — no MOVs, no PTC thermistors, sometimes just a wire link where a component should sit. That last one is the reason counterfeit meters are dangerous rather than merely disappointing.

If a seller will not allow the case to be opened on a used instrument, that is information in itself.

What this means when buying used

The practical rule is that provenance matters more than price. Equipment sourced from a documented liquidation, a service company fleet or an OEM trade-in carries a chain you can reason about. Equipment sourced from an anonymous marketplace listing does not.

Ask the seller directly how the unit entered their stock, whether they verified the serial, and whether they have opened it. A dealer who has done the work will answer immediately and specifically. A dealer who has not will change the subject to price.

Common questions