Counterfeit industrial components are not a rumour. Contactors, circuit breakers, PLC modules, sensors and drive keypads are all copied, and the copies have improved enough that the obvious tells — misspelt logos, glue on the case, a plate printed at the wrong angle — now catch only the worst of them.
The defence that works is a routine applied to every incoming part from a source you have not bought from before, not a single clever test.
Before it ships
Most counterfeits are caught by paperwork, not by inspection.
- Ask where the unit came from. A good supplier can tell you: cleared stock from a named distributor, a decommissioned line, a repair inventory. "Our warehouse" is not an answer.
- Ask for photographs of the actual unit, not a catalogue image — the rating plate readable, the packaging, and the connector side. Compare the article number and functional version against what you ordered.
- Compare the price to the market. A part that is 70 % below every other offer is telling you something. It may be a genuine clearance; it is worth asking which.
- Prefer a supplier with a verified company record, and read what other buyers said. On this site verification means the company's registration, VAT id and a working business contact were checked — it is a statement about the company, not about a specific unit.
Packaging
Genuine industrial packaging is boring and consistent. Look for:
- A label with the article number, a batch or serial number, and a date code that is plausible for the part's production run.
- Consistent print quality: the same font, the same shade of ink, the same barcode symbology as other units of the same family you already own.
- Anti-static bags that are actually anti-static (pink or metallised, not clear polythene) for electronics.
- No mixed branding inside one box.
An original part in a plain box is normal on the surplus market — stock is repacked all the time. A copied label is not normal, and that is what you are looking for.
The rating plate and the case
Put the new unit next to a known-genuine one of the same type. Almost everything a counterfeiter gets wrong is visible in a side-by-side comparison:
- Plate text. Laser-etched or high-quality printed on genuine parts; often slightly blurred, thicker or subtly different in kerning on copies.
- Certification marks. CE, UL, CSA, TÜV, ATEX marks should be crisp and correctly proportioned. A UL mark without a file number, or a certification the family never held, is decisive.
- Serial and date codes. Present, plausible and consistent between the plate, the label and any internal marking.
- Moulding. Look at the seams, the ejector-pin marks and the screw bosses. Injection tooling is expensive to copy well; counterfeits often have softer detail and slightly different textures.
- Weight. Copies are frequently lighter. A contactor with less copper in the coil and less silver in the contacts weighs less, and a kitchen scale will tell you.
Opening it up
Where the part allows it without voiding a warranty, the inside is where the differences are largest.
- Contactors and breakers: look at the contact tips. Genuine silver-alloy tips are substantial and evenly formed. Check the coil's wire gauge and insulation quality.
- PLC modules and drives: the PCB should be cleanly manufactured with proper solder joints, no hand-rework on a supposedly new unit, and branded components from the manufacturers the original used. A board with no silkscreen revision, or with obviously mixed component brands, is a warning.
- Connectors: plating quality and retention force are hard to fake cheaply.
Behaviour
Finally, test it where you can:
- Coil pick-up and drop-out voltage on a contactor, against the datasheet.
- Contact resistance, if you have a micro-ohmmeter.
- A drive under load rather than at no load — counterfeit and failed-refurbished power stages usually pass a no-load spin.
- For a PLC module, a full I/O channel test rather than a power-up LED check.
If you think you have one
Stop, photograph everything before you disassemble further, and contact the supplier with the specifics. A legitimate supplier who was themselves supplied a fake will want to know, and will usually take it back immediately. If they will not, report it — on this marketplace that is the report button on the offer and the supplier page, and a substantiated counterfeit report is grounds for removal.
Do not install it "just for now". A counterfeit contactor that welds, or a copied breaker that does not clear a fault, is a safety failure, not a commercial one.