[elossenen]

Question: Is it safe to answer a mobile phone while it is plugged in and charging the battery.
I have been told it is not, but have often done so.
Is it just luck that I'm not (eg burned a la some kind of "short") ; is there some risk and if so how does it work?

[Mereebirl]

Question: Is it safe to answer a mobile phone while it is plugged in and charging the battery.
I have been told it is not, but have often done so.
Is it just luck that I'm not (eg burned a la some kind of "short") ; is there some risk and if so how does it work?

Perfectly safe. I have no idea what these people are talking about. AFAIK the voltage is stepped down to very safe levels in the bit that plugs into the wall and the wire, connector and phone are all using very low voltages.

[jarsbars]

Question: Is it safe to answer a mobile phone while it is plugged in and charging the battery.

Yep.
Just be carefull not too move around too much, and have the phone jerked out of your hand when your reach the limit of the cord.
Hitting the ground isn't good for them.

[aabbaDE]

Thanks Twoy.
I checked the manual and although it was a cursory check I figured such a thing would BE IN UPPERCASE at least, but couldn't find any reference to it at all.

[Aozenee]

and chuckling @ Grant's remark ... I bet that's happened before today.

[rxnixoncom]

There was some urban myth going around a few years ago about some guy who was killed while talking on his phone while it was on charge. I can't remember the details, it might have been a lightning strike or it might have been complete rubbish

[BebopVT]

I bet some people have been killed while talking on the mobile phone.

[popsicesHoupe]

There was some urban myth going around a few years ago about some guy who was killed while talking on his phone while it was on charge. I can't remember the details, it might have been a lightning strike or it might have been complete rubbish

A lightning strike on a landline while you're using it could easilly kill you.
One coming through the mains & a charger then through a mobile phone; it's possible. But like a whale turning into a vase of flowers, not very likely.

[topcasinobonua]

I bet some people have been killed while talking on the mobile phone.

I can't find the article, but there was a recent report about the year on year indcrease in pedestrians being injured & killed. Walking & texting with your brain disconnected appears to be about as healthy as driving while blind drunk.

[Kemapreedasse]

Using a cell phone while charging poses a serious threat of electrocution:

http://www.snopes.com/horrors/techno/cellcharge.asp

Fortunately we don't have cell phones in Australia, we have mobile phones.

I'm not sure about prisons though, there may be cell phones there.

[SypeKifef]

Using a cell phone while charging poses a serious threat of electrocution:

http://www.snopes.com/horrors/techno/cellcharge.asp

Fortunately we don't have cell phones in Australia, we have mobile phones.

I'm not sure about prisons though, there may be cell phones there.

[mtvlover571]

A lightning strike on a landline while you're using it could easily kill you.
One coming through the mains & a charger then through a mobile phone; it's possible. But like a whale turning into a vase of flowers, not very likely.

Yes. it was actually being aware of the landline issue that made me ask; there's always the possibility I have missed something.

[chinesemedicine]

I can't find the article, but there was a recent report about the year on year increase in pedestrians being injured & killed. Walking & texting with your brain disconnected appears to be about as healthy as driving while blind drunk.

Yes.
A great illustration irl, that involved only embarrassment was on youtube of a young woman texting and inadvertently walking into a fountain in a shopping mall.

[DongoSab]

Anyhow, thanks for the answers.

I'll pass them along.

[Thydaysuh]

The charger has a certain isolation voltage maximum between mains and the output of the charger. Could only guess what the requirements may be, which'd be somewhat different to what it may be in practice, and regarding the latter there are different types of insulation failure or flashover.

In the case of a lightning storm the risk is generally low, but depends on what of the mains power is from overhead lines. The effectiveness of any surge diverters or suppressors on the line too, and the effectiveness of the earthing system are involved.

[minowz]

Just a guess but reckon the insulation/isolation would have to be able to sustain at least the peak voltages associated with three phase mains power, from different sources + some for spikes.

Depending on what parts of the circuit, the insulation properties may vary from 500V-3KV as may be relevant to the question. There are of course layout proximity considerations, and temperature and humidity considerations in design layout.

A lot of it comes down to the insulation/isolation between transformer windings and the optocoupler [if used]. Possibly in some designs no transformer is used, can't be sure. Doubtful though, as is probably a requirement. In some applications have seen multiple series capacitors used for isolation, but that may not be practical in charger designs.

http://www.onsemi.com/pub_link/Collateral/DN06009-D.PDF

[EnvellFen]

Most serious overvoltage consideration probably assume the neutral mains is grounded via some building grounding system, so the front-end mains input then DC high voltage would have any components like in the example C1, C2A, C2B exceeding their maximum voltage and dialectric puncturing. It has no dedicated protection components at this point in the example, but the rectifier filter/low pass filter capacitors will have dielectric breakdown and punch through at some voltage above their ratings.

After this point in the schematic T1 [transformer] and U2 [optocoupler] are the real protection. They separate/isolate the mains and higher voltage DC on the left from the low voltage on the right for charging the battery. T1 steps the voltage down and provides isolation. U2 sends some sample of what's happening on the low voltage on the right side back to the left higher voltage side - feedback for regulating voltage, maybe current sensing, limiting, possibly no-load standby.

Chip U1 on the bottom left is the power switcher, which uses the feedback mentioned above to probably control duty cycle or pulse width. If you look at the arrows in the optocoupler U2 you can see the direction of the feedback from output back to the high voltage side. Optocouplers are an encapsulated LED emmiter and receiver in which case the spacing/barrier between the two provides isolation. You can build them for greater separations of course. Like when you operate your TV remote control you could say you are opto-isolated ;-).

http://en.wikipedia.org/wiki/Opto-isolator

Not sure all common plug-pack mobile phone chargers have optocouplers. Given its such low power there are probably alternatives.

The danger is somewhat dependent on what other loads are connected into the same circuit and same switchboard [assuming single phase supply]. All the other things connected offer possible diversion points for any spike.

Generally the closer any lightning hit is to the building you're plugged into the greater the possible danger. For some humour will throw in that if you unplugged everything else in your house but kept your mobile phone connected this'd be likely worse than having other stuff plugged in ;-).

[lalffibra]

A lightning strike on a landline while you're using it could easilly kill you.
One coming through the mains & a charger then through a mobile phone; it's possible. But like a whale turning into a vase of flowers, not very likely.

Why is there such a difference in the likelihood of being killed between using a landline and using a mobile phone on charge?

(Sorry transition to formula, I didn't understand your posts on the subject )

[beepbeet]

Why is there such a difference in the likelihood of being killed between using a landline and using a mobile phone on charge?

When you get a lightning strike on (or extremely close) to the phone line, the only place for it to go to ground is through the phone line. If you happen to be holding the phone, then you become part of the path back to earth.
When it hits on (or near) a power line, there are many more paths back to earth, and with the low voltage section of the charger being electrically isolated from the mains side, and the outside of the phone isolated from the electronics inside, the likely hood if the strike going through you is really, reall, really small.[/QUOTE]

I used to know a Tesltra tech who did a call out to a house that was hit my lightning at Humpty Doo about 20-25 years ago. The lightning hit the shed, ran along the clothes line between the shed & the house, and then went through the house electrics. There was a burnmark down the wall & a large black mark where the phone used to be attacthed to the wall. Almost all the light fittings were either burnt out or blown off of the roof/wall. That was a rather exceptional strike, but it gives you an idea of the energy involved.

[ThisIsOK]

Telstra use arrestors with independent earth stake where the cable outside connects to the internal house phone wiring [junction box], well in the country they do. GDTs mostly have seen.

Still your phone wiring can be fried off the wall with a very near lightning hit, as happened at the wife's house when she was young, in fact as was told the SWER transformer on the pole outside the house was destroyed also. Think it popped oil out the top, which ETSA were glad to know of as saved them spending a day isolating the short on the distribution system.

http://en.wikipedia.org/wiki/Surge_protector