Author Topic: Why some people died in their bath after smartphone dropped into water ?  (Read 14125 times)

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Offline tigrouTopic starter

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There is several cases (reported by media) of people dying after their smartphone (while being charged) dropped into the bath and electrocuted them.

AFAIK most USB chargers deliver max. 5V, which is non lethal.
Because of ohm's law, you need a much higher DC voltage than that to get enough current flowing trough your body and killing you.
So I don't understand how it is possible.

The possible explanations I see are :
- they get killed not because their phone dropped into the water, but because the charger itself dropped into water (eg: not plugged into socket directly but plugged into an extension coord).
- the human body resistance is considerably lower while in the water, making 5V (and enough amps) dangerous.
- under some conditions, some chargers (eg : counterfeit ones with improper isolation) will deliver more than 5V.
- lithium battery capable of delivering high voltage when dropped into water while being charged.
 

Offline BravoV

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #1 on: January 27, 2020, 09:35:23 am »
... possible explanations I see are :

...

You missed this one too ...

The phone plunged into the bath-tube, either connected or NOT connected to the charger (doesn't matter), and the owner panicked and did some jerk movements, as bath room is wet & slippery, and then fell down and got knocked in the head unconsciously, and drowned in the bath tube.  :-DD
 
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Offline thinkfat

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #2 on: January 27, 2020, 09:38:30 am »
I suggest watching bigclive on YT tearing down cheap USB wall warts for an explanation.
Everybody likes gadgets. Until they try to make them.
 
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Online iMo

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #3 on: January 27, 2020, 10:10:01 am »
The most people die from heart attack when they realize their lovely smartphone dropped in the water :)
Readers discretion is advised..
 
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Offline atmfjstc

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #5 on: January 27, 2020, 12:24:39 pm »
- the human body resistance is considerably lower while in the water, making 5V (and enough amps) dangerous.

Don't take this as 100% medical advice, but AFAIK, although the resistance of human skin is considerably lower when wet, it is still not low enough for 5 volts to be lethal. You'd need to apply the voltage directly to your internal organs to get a serious effect.

- lithium battery capable of delivering high voltage when dropped into water while being charged.

A cell's voltage is fundamentally limited by the electochemical potential of its electrodes and can never go much above 4-5V no matter how you abuse the battery. To get a higher voltage you need an external circuit with some inductance. Or put more cells in series, but I don't think they use more than 7.4V in mobile phones.

Looking at the two articles mentioned it seems the real causes of such electrocutions are:

- The charger itself being dropped in water (which means the full line voltage going into the charger is now applied to water)
- The charger having an isolation fault which means the charger's outputs are at full line voltage relative to ground, and thus the phone's electronics. Dropping the phone in the water is thus equivalent to dropping the mains cord in the water. In fact you don't even need to drop the phone in the water if it has a non-insulated metal chassis....
 
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Offline Prehistoricman

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #6 on: January 27, 2020, 01:31:56 pm »
- The charger having an isolation fault which means the charger's outputs are at full line voltage relative to ground, and thus the phone's electronics. Dropping the phone in the water is thus equivalent to dropping the mains cord in the water. In fact you don't even need to drop the phone in the water if it has a non-insulated metal chassis....

Important thing to note here: this only poses an issue when the bath's metal fittings are earthed. Otherwise, there is no complete circuit and very little current would flow.

Offline donotdespisethesnake

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #7 on: January 27, 2020, 02:52:01 pm »
I suggest watching bigclive on YT tearing down cheap USB wall warts for an explanation.

I think that is likely to be #1 reason.

We don't know if the phone was dropped in the bath as a cause or result of death. It's possible a shock was received by holding the phone with damp/wet hands.

Also, is it possible to get a shock across the chest without a path to Earth required? For example, hold a live and neutral wire in each hand, and the loop through the arms and chest will provide a circuit. A voltage across the chest (and therefore the heart) is the most dangerous path.
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Offline mikerj

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #8 on: January 27, 2020, 03:21:44 pm »
Important thing to note here: this only poses an issue when the bath's metal fittings are earthed. Otherwise, there is no complete circuit and very little current would flow.

They will be bonded to earth in many/most houses if copper pipes are used, and there will likely be leakage down a wet waste pipe.  Even if the metal parts were isolated a bathtub full of water likely presents a high enough capacitance to ground to cause an uncomfortable amount of current to flow.
 
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Offline ejeffrey

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #9 on: January 27, 2020, 07:49:03 pm »
There is several cases (reported by media) of people dying after their smartphone (while being charged) dropped into the bath and electrocuted them.

AFAIK most USB chargers deliver max. 5V, which is non lethal.
Because of ohm's law, you need a much higher DC voltage than that to get enough current flowing trough your body and killing you.
So I don't understand how it is possible.

The possible explanations I see are :
- they get killed not because their phone dropped into the water, but because the charger itself dropped into water (eg: not plugged into socket directly but plugged into an extension coord).
- the human body resistance is considerably lower while in the water, making 5V (and enough amps) dangerous.
- under some conditions, some chargers (eg : counterfeit ones with improper isolation) will deliver more than 5V.
- lithium battery capable of delivering high voltage when dropped into water while being charged.

You missed: it is just an urban legend and didn't actually happen.  Just like the guy supposedly killed by the 9V battery in an ohm-meter by piercing his skin with the probes.

But defective mains isolation and knocking an extension cord into the bath are both possible as well.
 

Offline james_s

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #10 on: January 27, 2020, 07:54:23 pm »
Considering what I have seen inside cheap knockoff phone chargers, it would not surprise me in the least if someone is shocked, potentially lethally by an isolation fault, especially in 240V land.
 

Offline Refrigerator

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #11 on: January 27, 2020, 08:12:04 pm »
There are chargers that have their primary and secondary winding wires lay on each other without any additional insulation and this could very easily cause an electrical connection between the two if the enamel insulation on the wire got damaged.
DiodeGoneWild made some videos on dodgy chinese chargers:

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Offline AVGresponding

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #12 on: January 27, 2020, 08:19:43 pm »
I suggest watching bigclive on YT tearing down cheap USB wall warts for an explanation.

Some of the gear he pulls apart is hilariously scary; it's not unusual for him to discover line voltage directly on the USB socket   :wtf:
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Offline tooki

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #13 on: January 29, 2020, 09:24:32 pm »
Remember when BigClive joked one time about the next thing being the Chinese making a USB charger from a capacitive dropper, and then within a year, he tore down the “gay death dalek” camping light which, lo and behold, had a capacitive dropper USB charger? 240V mains on a USB port...  :clap:

« Last Edit: January 29, 2020, 09:27:48 pm by tooki »
 

Offline Brumby

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #14 on: January 29, 2020, 11:45:06 pm »
AFAIK most USB chargers deliver max. 5V, which is non lethal.
Because of ohm's law, you need a much higher DC voltage than that to get enough current flowing trough your body and killing you.
So I don't understand how it is possible.

The possible explanations I see are :
- they get killed not because their phone dropped into the water, but because the charger itself dropped into water (eg: not plugged into socket directly but plugged into an extension coord).
- the human body resistance is considerably lower while in the water, making 5V (and enough amps) dangerous.

- lithium battery capable of delivering high voltage when dropped into water while being charged.
Forget about the 5V.  The actual stated voltage delivered by the charger has NOTHING to do with the problem.

Quote
- under some conditions, some chargers (eg : counterfeit ones with improper isolation) will deliver more than 5V.
This is the area your thinking needs to explore.  Aside from the obvious situation of a charger being dunked in the bath water where mains can come into direct contact with the water, in poorly designed/constructed chargers, other paths can exist for mains power to go where it shouldn't

See other posts above for links to examples.
 

Offline KL27x

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #15 on: January 30, 2020, 12:30:29 am »
Even considering the possibility of shoddy chargers, that had nothing to do with the majority of the deaths.

E.g., one girl thought to have touched a frayed mains extension cord while in the bath. One young man thought to have set his CHARGER (not the phone) on his chest while laying in the bath; i.e. he set the extension cord and charger plug directly on himself. Both peeps plugged the extension cord into a non-GFI outlet.

If the problem was shoddy chargers, wouldn't they be destroying phones, regardless of the vicinity to a bathtub?
« Last Edit: January 30, 2020, 12:34:10 am by KL27x »
 

Offline JustMeHere

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #16 on: January 30, 2020, 01:09:13 am »
The case I know about, the girl had her charger plugged into a damaged extension cord.
 

Offline Brumby

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #17 on: January 30, 2020, 01:13:54 am »
If the problem was shoddy chargers, wouldn't they be destroying phones, regardless of the vicinity to a bathtub?
Mobile phones are completely floating, electrically.  Mains voltages would cause the entire device to attain a potential with respect to the world around it, but internally, there is no such risk.

But add a path to ground and things change.
 

Offline Brumby

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #18 on: January 30, 2020, 01:18:39 am »
Even considering the possibility of shoddy chargers, that had nothing to do with the majority of the deaths.

E.g., one girl thought to have touched a frayed mains extension cord while in the bath. One young man thought to have set his CHARGER (not the phone) on his chest while laying in the bath; i.e. he set the extension cord and charger plug directly on himself. Both peeps plugged the extension cord into a non-GFI outlet.
The case I know about, the girl had her charger plugged into a damaged extension cord.

Thank the Media for sensationalising such stories.  They take the attention grabbing subjects of "phones" and "injury/death" in order to get an audience - especially for headlines - and don't get too excited about being more detailed until later in the article, if at all.
 
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Offline amyk

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #19 on: January 30, 2020, 01:20:08 am »
Even if there was an isolation fault, a phone dropped into the tub would make the current seek the ground, it won't take a detour through your body --- unless you grab it and it's metal, which is what I suspect happened in a lot of cases.
 
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Offline james_s

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #20 on: January 30, 2020, 01:27:51 am »
It's going to be people holding onto their phone while sitting in the bath with the phone plugged into the charger. I wouldn't do that myself but it's very common behavior, people have run down the battery and want to sit there watching videos or playing games on their phone so they plug it in. Lots of phones have metal components that you can touch easily, and if a charger fault causes those to be live then you're in for a bad experience.
 

Offline Jwillis

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #21 on: January 30, 2020, 01:38:27 am »
Even if there was an isolation fault, a phone dropped into the tub would make the current seek the ground, it won't take a detour through your body --- unless you grab it and it's metal, which is what I suspect happened in a lot of cases.

That's not entirely true . The current does not take a direct path in water to a common ground or on contact with the earth, but creates a varying potential radiating outward from the point of contact.  So being a body of water can still be lethal as one point of the human body can be put at a different potential than another part of the human body. It only takes a few milliamps to cause heart failure. And in a wet environment the resistance from one potential and another can be quite low only requiring very small voltages for the current to cross potentials.
 
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Offline KL27x

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #22 on: January 30, 2020, 04:11:48 am »
Quote
It's going to be people holding onto their phone while sitting in the bath with the phone plugged into the charger.
But has this ever happened? I personally do not know of any such cases.

Quote
Mains voltages would cause the entire device to attain a potential with respect to the world around it, but internally, there is no such risk.

But add a path to ground and things change.
If this CAN actually happen, someone could demonstrate it and put it on Youtube. Just take one of these chargers that is somehow putting full mains (and mains - 5V) directly to the phone (full mains, not high impedance capacitive coupling of microamps) and showing how you plug the usb cable into the end of a hot dog and then grounding the other end and instantly cooking the weiner.

I don't see how this can happen and get sold like that. Nothing coming out of the charger should be directly connected to mains. If you cut the cable and touched it without wearing shoes, you would get shocked. If you were standing on wet ground, you could be electrocuted. This does not compute with realworld experience with cheap PSU's. I mean, if you touch the DC output (either the + or the -; dunno which; try both?) to ground, this would blow your breaker? You're saying that one of the DC output wires is direct mains!? I don't believe this is for sale and making it to the US even through Alibaba.

They can be dangerous if they fail. Dropping the DC output end into water/ground should not cause any problem other than short/current-limiting, unless the thing has also happened to fail in some other way at the same time?  :-//
« Last Edit: January 30, 2020, 04:36:45 am by KL27x »
 

Offline Jwillis

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #23 on: January 30, 2020, 04:48:54 am »
I think theirs more to these stories than what is really being told. The average USB charger cable is around 3 feet long or about a metre. Electrical code states that any power outlet must be a minimum of 6 feet or 2 meters from the bathtub or shower or toilet . So as the OP stated it's quite likely that an extension cord was used at the time of insistent . GFCI receptacles are supposed to be installed in bathrooms but I have seen these plugs replaced with standard wall receptacles.
So in a scenario of no GFCI with an extension cord charging a smart phone while taking a bath add up to a very bad day for the victim.
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Offline AVGresponding

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Re: Why some people died in their bath after smartphone dropped into water ?
« Reply #24 on: January 30, 2020, 05:54:12 am »
Quote
It's going to be people holding onto their phone while sitting in the bath with the phone plugged into the charger.
But has this ever happened? I personally do not know of any such cases.

Quote
Mains voltages would cause the entire device to attain a potential with respect to the world around it, but internally, there is no such risk.

But add a path to ground and things change.
If this CAN actually happen, someone could demonstrate it and put it on Youtube. Just take one of these chargers that is somehow putting full mains (and mains - 5V) directly to the phone (full mains, not high impedance capacitive coupling of microamps) and showing how you plug the usb cable into the end of a hot dog and then grounding the other end and instantly cooking the weiner.

I don't see how this can happen and get sold like that. Nothing coming out of the charger should be directly connected to mains. If you cut the cable and touched it without wearing shoes, you would get shocked. If you were standing on wet ground, you could be electrocuted. This does not compute with realworld experience with cheap PSU's. I mean, if you touch the DC output (either the + or the -; dunno which; try both?) to ground, this would blow your breaker? You're saying that one of the DC output wires is direct mains!? I don't believe this is for sale and making it to the US even through Alibaba.

They can be dangerous if they fail. Dropping the DC output end into water/ground should not cause any problem other than short/current-limiting, unless the thing has also happened to fail in some other way at the same time?  :-//

Ebay and Alibaba are full of this cheapo dangerous tat. There are countless youtube videos, search bigclivedotcom to start.
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