UL report claims that 99% of counterfeit iPhone chargers fail safety tests [pdf]
library.ul.com
library.ul.com
Does anyone know what is the "high voltage" that is applied, and what is the threshold for the current that is being tested?
The general requirements are linked from the listing page: http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/sh...
The loads are described in ANSI/UL standard 60950 which is incorporated by reference https://standardscatalog.ul.com/standards/en/standard_60950-...
Which is a round about way of saying that UL knows what it is doing and that the tests for certification are not something that some bureaucrat made up for bureaucratic purpose. Underwriter's Laboratories is a data driven organization that's roughly been data driven since a century before anyone heard of data driven organizations.
It researches safety based on the hazards that actually spark insurance claims. Everything from roofing (think resistance to hail and wind) to ...well iPhone chargers. It's research is the reason people rarely get electrified in their home (e.g. the National Electrical Code requires 'listed devices' and that means UL or a similar testing and certification agency).
Anyway, I hope the links let you geek out.