Virtually every counterfeit Apple charger in a recent test posed a safety risk. The problem is not with reputable third-party chargers, but rather those falsely marketed as being produced by Apple themselves.
The test was carried out by US safety research firm UL on behalf of a British consumer watchdog. It purchased a total of 400 adapters from eight countries. The safety check involved putting a high voltage through the chargers to see if they were adequately insulated. Only three of the 400 chargers passed the test.
The organization said common ways to spot dangerous chargers were that they don’t easily fit into a socket, or that there isn’t a gap of at least 9.5mm (the width of a ballpoint pen) between the edge of the pins and the edge of the charger.
One safety difference is obvious: the Apple charger has much more insulation. The upper (high-voltage) half is wrapped in yellow insulating tape. Some components are encased in shrink tubing, there are plastic insulators between some components, and some wires have extra insulation. The counterfeit charger only has minimal insulation.
The build quality of the Apple charger is much higher. In the counterfeit charger, some components are visibly crooked or askew. While this doesn’t affect the circuit electrically, it indicates a lack of care in construction.