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Charging phone in bath

Old 18th Mar 2017, 13:38
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Charging phone in bath

Thing is that if desperate I might have been (and may still be?) tempted to use say a long USB cable to do this with the Mains electricity well out of reach.


Sadly as usual the news seem to be getting it wrong. At least one of these must surely be wrong.

https://www.theguardian.com/uk-news/...charging-phone
Tributes paid to Richard Bull, whose death was ruled accidental after he was killed when his phone fell into the water

Man dies charging iPhone while in the bath - BBC News
Richard Bull, 32, died when his iPhone charger made contact with the water at his home in Ealing, west London.
https://www.thesun.co.uk/news/311124...-on-his-chest/
Richard Bull, 32, is believed to have plugged the charger into an extension cord from the hallway and then rested it on his chest while using the phone
[What is IT? - The charger? - The extension cord? - The phone?]

So which article(s) are incorrect?

I find it difficult to believe that, absent the mains in the bath, dropping the charging phone in the water might have fatal results? 5V is after all surely 5V.

On the other hand, "balancing a mains extension socket on ones chest" when in the bath is clearly a bit daft, especially in a 240V country.

Can anyone shed any expert light on this?
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Old 18th Mar 2017, 13:42
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Originally Posted by jimjim1 View Post
Thing is that if desperate I might have been (and may still be?) tempted to use say a long USB cable to do this with the Mains electricity well out of reach.


Sadly as usual the news seem to be getting it wrong. At least one of these must surely be wrong.







[What is IT? - The charger? - The extension cord? - The phone?]

So which article(s) are incorrect?

I find it difficult to believe that, absent the mains in the bath, dropping the charging phone in the water might have fatal results? 5V is after all surely 5V.

On the other hand, "balancing a mains extension socket on ones chest" when in the bath is clearly a bit daft, especially in a 240V country.

Can anyone shed any expert light on this?
Water and electricity do not mix well
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Old 18th Mar 2017, 15:59
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The USB chargers mostly use an electrical design that allows a small percentage of the mains voltage through to charge low voltage devices. Very few of the cheaper systems use a transformer, which would, in theory, completely isolate the mains from the charger output. Instead, a capacitive dropper design is the normal choice for manufacturers, it is cheap, works well but has the disadvantage that one side of the circuitry is connected to the mains. The cheap chargers do not have any form of earth connection, so the output voltage is left floating with respect to earth. Under normal conditions this does not represent a problem.

If you run the back of your fingers along the metal side of a tablet computer or phone while it is plugged in and charging, you will probably feel a little tingle or vibration through your fingers. This is leakage current to earth passing through your body. It is at very low levels, microamps at best and normally completely harmless because your body has a resistance of at least a hundred thousand ohms when dry.

Step into a bath and you reduce the skin resistance dramatically, perhaps to a thousand ohms or less. This allows considerably more current to flow. Add some contaminants such as bath salts to the bath water, and the water conductivity is also vastly increased. Distilled water is effectively an insulator, but add some salt and it readily conducts electricity.

So the floating five volt charger appears pretty harmless, but because the voltage is floating with respect to earth, a much higher voltage can exist between the charger contacts and earth, approximately half of the mains voltage is normal, so 120 volts in the UK.

The next problem is that the mains voltage is not actually 240 volts, that is just the mean value of the sine wave voltage. The peak rises to 315 volts or thereabouts.

So there you are sitting in the bath with a five volt charger, but the actual voltage to earth from either contact is nearly 160 volts. The return earth connection is provided by the copper pipework to the bath. It only takes one milliamp of current to flow across the chest and heart to disrupt the normal heartbeat. An overall resistance of 160,000 ohms is required to limit current to this level. As mentioned earlier, the actual resistance of a body immersed in bath water is probably less than a thousand ohms. This would allow a current of 160 milliamps to flow, easily enough to kill.

Almost certainly, the charger being used in this incident was one of the cheaper after market ones sourced from the Far East, although any device connected to the mains in a bathroom represents a considerable risk to the user unless specifically designed and certified for such use.
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Old 18th Mar 2017, 16:44
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I commented on this sad incident on another thread as an example of the lack of awareness of danger many people have today. That was avery interesting post Gouli-Iwas not aware of the different charger types seeing the higher priced ones as just typical branded rip offs. Also was not aware that the instantaneous voltage on mains could be so much higher than 240 V which is quite enough o kill anyway.

In spite of the different types of charger etc is till find it ahrd to understand man of 32 did not realise
1 That you never ever ever mix water and electricity
2 That any charging device has at some point wire in and a wire out, the wire out may only be 5v but the wire in is regular mains.

A sad story
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Old 18th Mar 2017, 20:48
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If you must buy another after market charger and you don't want to pay the original manufacturer's price, the Ikea Koppla charger with three USB outlets is a very good and safe choice. So good, I bought four!
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Old 19th Mar 2017, 18:08
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Suggest that he could be a candidate for the Darwin award "http://www.darwin--awards.com/"
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Old 20th Mar 2017, 09:50
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GOULI, thanks for the exceptionally informative, illuminating, and interesting post. I've taken a full 240V shock accidentally (not in water), and I can tell you, it very quickly gets your full attention!

I was repairing a power tool, got a little "switched off" during repeated "power on" testing, and managed to insert a finger into a live active terminal, incorrectly thinking I'd turned the power off! No harm done, just gave me a good little recharge.

One thing about those small chargers that I don't like is their propensity to "light up" because of their relatively poor construction and poor quality insulation. Remember, you're reliant on possibly one or perhaps two, overworked, underpaid and lowly-skilled Chinese factory workers to ensure your house doesn't burn to the ground!

As a result, I never leave these things running unattended in an empty house. I've had a simple 3-pin male-female 240V extension lead connector, "arc up" via a straight-out short circuit, and it was pretty impressive to see!

The offending 240V connector assembly was in a workshop, running power to a pedestal drill. The power lead hung down from the wall and could swing in the wind that regularly blew through the often-open shop doors. Years of swinging in the wind created the conditions for the 240V connector short circuit.

I've also been informed that the cheap 240V electric kettles have been known to short circuit and cause fires, when the power switch at the wall is left on, but the kettle is off.
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Old 20th Mar 2017, 10:25
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Unless bathroom electrics are executed by someone with saddle sores, one will never see a switch lower than ceiling level and with a hanging cord.
Another tip, never take an electric fire into a bathroom.

I have reproached myself for being sarcastic.
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Old 20th Mar 2017, 10:45
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In Spain it's common to see mains plug sockets just above the wash basins
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Old 20th Mar 2017, 11:09
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With regards to electrical equipment in the bathroom, a friend installed a very fancy cabinet in his shower room. The cabinet formed from stainless steel was fitted with a Bluetooth audio system and heating pads to ensure the mirror on the front remained fog free. The system appeared to be working fine, until he touched the cabinet while shaving and received a shock. I was asked to investigate.

Everything in the cabinet was double insulated and insulation tests showed no leakage between the power leads and the cabinet. Tests also revealed that the cabinet itself was not earthed because power had been tapped off an old lighting circuit, which was so old it was not provided with an earth connection.

What was happening was that steel case of the cabinet was coupling as a huge extra turn to the low voltage transformer supplying power for the audio system. The cabinet was gradually charging up to 300 volts or so while it was in use with respect to earth. Touch the cabinet and you got a brief but severe shock, especially standing on a damp floor with wet feet! There was no electrical connection between the cabinet body itself and the mains, but still an electrical shock risk existed.

Once the cabinet was connected up properly to the mains supply with the cabinet bonded to earth and all the other bathroom appliances, everything was fine. This involved some heavy duty drilling through a double wall to route a proper power cable, which is why my friend had taken the easy option of tapping into the lighting circuit. Everything was working just fine until he used the shower and the cabinet had been powered up for some time.

Even simple electrical work carries risks if you don't fully understand what is going on.
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Old 20th Mar 2017, 13:36
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For heaven's sake - can't one even take a bath nowadays without feeling withdrawal symptoms from a phone!!
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Old 20th Mar 2017, 14:50
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On a humbler scale, when changing a lamp bulb, do not assume that the fact of having switched off at the wall, or at the lamp, means that both pins in the socket are safe - it ain't necessarily so !

A mains-testing screwdriver should be in every toolkit.

As for the chap who took his charger into the bath, suggest a candidate for "The Most Highly Derogatory Order of the Irremovable Digit" (remember, anyone ?)

Last edited by Danny42C; 20th Mar 2017 at 14:53. Reason: Forgot a word ! (happens at my age)
 
Old 20th Mar 2017, 14:57
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Back around 1993-4 I was living in Naples. Hot water to the bath was provided by a "scaldabagno" electric immersion heater above the bath. Water in Naples is very hard and soon after we moved into the house the immersion heater stopped working. The workman who arrived to repair the fault tried to drain it, but the calcium had blocked the drain tap. He then removed the heater element (with some difficulty) which was on the base of the cylinder and then started to drill out the built up calcium using a mains powered drill. He ignored my protestations and survived - at least for that day.
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Old 20th Mar 2017, 15:05
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We came perilously close to losing our daughter when the wire going through a smoothing iron's springy wire tensioner rubbed through and touched the metal spring coil. The iron was in those days, earthed.

Worst scenario: one hand on the earthed iron, and one on the springy thing. Her worst problem was the muscle strain from being thrown backwards.

I was one of the first folk I know of to protect my home with an RCCB (RCD OR RCB) It worked well.

I have a box of in-line computer lead breakers with 10mm sensitivity. Job lot from Bull Electrical on the south coast. "We're surprised they haven't sold better." the guy said to me. But folk back then just didn't realise that they were the most intelligent, brilliant invention since the wheel.
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Old 20th Mar 2017, 20:56
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depending on where youare in the world you can or used to be able to find some alarming socket /plug combinations. US Caribbean seemed one of the worst with flimsy two pin plugs and for higher powered devices a horrid earthed version that seemed to be made entirely of metal with some bits cardboard as spacers/insulators. I image they do not make them any more but on older devices who knows. we had a horrendous installation in my house with an undersink water heater and dishwasher on same circuit-turn on washer hot water but not hot enough runs into dishwasher. -cools down water in heater. On comes heater in dishwasher AND undersink heater at s ame time and zap off goes the power. So if you dont remember to turn one off then the other and the first back on it wont work and then off to the astonishing fuse board with all sorts of naked connections and weird fuses made of glass or lumps of ceramic with exposed metal ends that pushed into big copper sprung forks

The standard Euro plug is probably the best followed by our own and then maybe S Africa who have a sort of hybrid European/Aussie device. I think in Northern Europe we have much the safest designs and installations of anywhere -so long as people understand enough to know that you do not touch anything without turning off at the consumer unit or in this case mix electricity and water ever. What did people under 35 learn at school??
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Old 20th Mar 2017, 21:31
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While neon screwdrivers can give an indication of a live connection, lighting conditions and various combinations of wiring can result in the neon glow being invisible or absent. Floating high voltages will not necessarily light a neon bulb. A far safer alternative is a non contact voltage tester. These are available for a few pounds from most DIY and trade outlets. They run off a couple of AA or AAA batteries, so always check that the voltage tester works on a live part of the circuit before checking a suspect bit is truly powered down! Fitting a couple of Lithium batteries should ensure these devices work okay for up to ten years. Alkaline and zinc carbon batteries need frequent checking to make sure they are not leaking or have run flat.

In the absence of nothing better, a neon screwdriver can give an indication that a circuit is live, but are you comfortable betting your life on it? A suitably rated multimeter is my personal choice when checking for voltages.
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Old 20th Mar 2017, 21:53
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Had an interesting mains incoming fault the other week.
Of the infeeding 11KV 3 phases to the local substation two had shorted and gone bang.
That left one phase live - mine.
The result was "interesting"
The RMS value of the incoming supply to the house shot up from 240 volts to 281Volts before 'settling down' to 275Volts.
...and there it sat - while I got on the phone and after about an hour they wound down the tap changing transformer somewhere further back to reduce it to around 250volts while they pondered what to do next. (install a generator on a lorry outside the local substation was the answer while the cable was mended over the next few days)
I noticed it as I was in a room with an incandescent lamp which suddenly got much brighter and my computer's UPS intervened to safeguard things as the volts were way too high.
I was rushing round the house switching things off!
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Old 20th Mar 2017, 22:50
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Originally Posted by Danny42C View Post
On a humbler scale, when changing a lamp bulb, do not assume that the fact of having switched off at the wall, or at the lamp, means that both pins in the socket are safe - it ain't necessarily so !
!In our previous house, the light switches were incorrectly fitted in the neutral lines, not the live, thus leaving every fitting live when off!
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Old 21st Mar 2017, 03:04
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andytug

Switching the neutral wire was thought safer a long while back when switches were made of brass and ebonite and there was no earth connection in the lighting circuits. The high voltage was kept out of harms way near the ceiling. Older properties can conceal a multitude of traps for the unwary electrician or DIYer.

Even further back, electrical wiring consisted of two bare copper conductors stapled to the wall and covered with a wooden lath. I am led to believe my grandfather wired up several hundred new build houses in the Leyton area of London using this method as late as the 1920s.
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Old 21st Mar 2017, 04:26
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I don't touch anything electrical without giving everything a going over with a multimeter. Saved me grief twice. Once when someone (a company electrician) had wired the neutral (not the active) to the main isolation switch to a machine I was working on..
After that incident they installed padlocks on the isolation switch so I had to wait hours for someone to turn up to isolate. I'd do my stuff on the machine then wait hours again for the de isolation in order to check my work. PIA! Especially when I needed multiple isolations to find and fix the fault. Lucky I was paid by the hour but talk about frustrating....
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