Caption of picture:

The devastated family found Thanyaluck in her bedroom (pictured) with the charred phone in one hand and a schoolbook in the other

i.dailymail.co.uk/1s/2020...33199084-8734399- image-a-48_1600163418224.jpg

It makes you wonder how such electrical accidents can happen. Maybe here was no voltage regulator on the electrical system. But this is basic physics. :-/

It makes you wonder how such electrical accidents can happen. Maybe here was no voltage regulator on the electrical system.

Phone chargers begin with a transformer that steps the voltage down from a dangerous 120 or 240 (depending on the country) volt AC home outlet to a nominal DC voltage around 5 volts. The DC voltage can't kill anyone, so this type of problem would indicate a faulty charger. Some kind of a short in the phone charger sent AC voltage into the phone which the phone circuitry is not designed to contain.

Some kind of a short in the phone charger sent AC voltage into the phone which the phone circuitry is not designed to contain.

I would say you are right. It was a faulty charger. ;)

The DC voltage can't kill anyone, so this type of problem would indicate a faulty charger. Some kind of a short in the phone charger sent AC voltage into the phone which the phone circuitry is not designed to contain.

China has 220/50Hz system. Also they use 2-prong plugs (Type A with same size prongs.) Seems to me that even if the 220 went directly into the phone, it would instantly fry the entire circuitry, thereby causing a massive short circuit...unless her hands were wet.

From CNN:

It's not clear what kind of charger Ma was using, although her sister said she had bought her phone in December at an official Apple store and was using the original charger to recharge the device when the incident occurred, according to a post on Sina Weibo, a Chinese microblogging site that is similar to Twitter.

Mixing smartphones with water is another safety concern. Ma's family said online that she left the bath to answer the phone. Water is an excellent conductor of electricity, and moisture on the skin can lower a person's natural resistance to electric shock, experts say.

faulty charger

Yes, undoubtedly. (I design electronic products for a living.)

even if the 220 went directly into the phone, it would instantly fry the entire circuitry

Not necessarily. It is possible that the charger's galvanic isolation could fail while the charger was still supplying the correct low voltage DC to charge the phone's battery. If the galvanic isolation (provided by Ping's transformer) failed, the AC line voltage (120V or 240V) would appear between the phone and ground. In that case, touching the phone -- especially with wet hands -- could be fatal. If the phone was charred, it's likely that the charger doubly failed: it lost its galvanic isolation, and it sent the wrong charging voltage to the phone, and might well have instantly fried the entire circuitry, as you said. But unfortunately the phone's circuitry frying wouldn't eliminate the danger posed by the loss of galvanic isolation.

Water is an excellent conductor of electricity, and moisture on the skin can lower a person's natural resistance to electric shock, experts say.

Pure water is actually almost non-conductive for electricity. It's the stuff mixed into the water that conducts much better. The reason why dropping a hair dryer into a tub of water where someone is bathing is because the body of a person in it conducts electricity so much better than the bath water does, so the electricity decides to treat you as part of the electrical circuit.

Faraday cages, by contrast, conduct electricity much better than the person inside, so the electricity takes the easy route through the cage and ignores the people inside it.

Soapy water conducts but not as well as the human body does.