Short circuit of inferior charger at high voltage can lead to fatal electric shock

Ken Shirriff, a hardware engineer from the United States, wrote an article on his personal blog discussing whether counterfeit chargers could lead to electric shock among mobile phone users. He believed that, in cases where insulation standards are not met, electric shock is indeed possible.

Recent reports have indicated that Ma Ailun, a flight attendant for China Southern Airlines, died from electric shock while making a call with her iPhone while it was charging. If she used a cheap or counterfeit charger, then such a scenario is technically completely possible.

There is 340 volts of direct current electricity inside chargers, which is enough to be fatal. In cheap chargers, the distance between the output end and the 340-volt component may be less than 1 millimeter, far less than the recommended safety distance.

In certain situations, short circuits can occur in the charger's output, resulting in higher voltage being transmitted through the USB cable. If the user is nearby, such as touching a grounded metal surface with their hand, then electric shock is entirely possible. And in damp environments, such as bathrooms, such short circuits are more likely to occur.