I often wonder how many of these counterfeits are coming off the same line as the real deal, just off the books, hence SqD etc is not getting their royalty.
Of course there are probably a lot of things like AFCIs that are actually the cheaper GFCI with an AFCI stamp on them. I am not sure how you would tell without breaking them open and comparing numbers on chips. The test button would still trip them and a tester *might* work or might not, same as a real AFCI. They would still nuisance trip on some circuits.
How would you know
