If you drop it in the bath then the risks you face can't be mitigated by any SMPS design features.
Thoughts?
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All chargers are galvanically isolated by means of a transformer as required by EN60950.
Only the ones that conform. ESF (I think it was) found some that only contained a capacitor!
EDIT: and a rectifier, of course!
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Yes, true. But people should at least pay attention to what they are buying. If you buy a charger for a few pounds off eBay then you only have yourself to blame. (IMO)
That still provides isolation. Capacitive isolation rather than galvanic, but it's still safe as long as the capacitor has the right characteristics. (Possibly not legal though.)
This story is not about fake chargers or cheap imports, it's about droping a 240 Volt device into the bath.
More to the point it's about dropping a live extension socket into the bath.
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If the 230Vac charger or extension lead was dropped into the bath then it has nothing to do with charger 230 volt and a bath do not mix, but then why would they want to contact Apple, it has nothing to do with Apple product it's all about some one being rather silly. However this
is an extension lead, I would not be unduly worried if I saw some one using an extension lead of that type. If it is just the phone which dropped in the water or what we would consider as being SELV then looking at a completely different thing.
There has to be some special consideration I suppose as to who is using the device. I had my mother put an extension lead in a bucket of water because she saw a red neon and thought it was on fire, alzheimer's and poor eye sight combined caused her to do some thing we had not expected, it was after this I got house rewired so all is now RCD protected. As well as the old we also have the young and people who do not have the mental capacity to see the danger, near every item we buy today has some instruction as to not being suitable for people with a reduced mental capacity.
Yet when I went to do PAT testing in a school I was shocked to see no RCD protection on most sockets, the same applies to hospitals and nursing homes they rely on the teachers, and nursing staff to ensure the people do not hurt themselves, so not read an Iphone instruction, does it state an age it is suitable for? We do tend to give vulnerable people phones, and these people often can't read small print, so they should have instructions to say where they can be used, to say you should not use it in wet conditions would mean you can't use it when it's raining which would not work, it is an out door device so should be reasonable water proof, adverts now show the phones being dropped into water and retrieved still working so we are shown by adverts suitable for use in the bathroom.
We here stories about people in USA expecting their automatic cars to do far more automaticity than they can, instead of the automation being used as a safety back up, it was used to self drive the vehicle, so I suppose a large notice only charge in doors in dry conditions is a reasonable notice to put on the phone.
There has to be some special consideration I suppose as to who is using the device. I had my mother put an extension lead in a bucket of water because she saw a red neon and thought it was on fire, alzheimer's and poor eye sight combined caused her to do some thing we had not expected, it was after this I got house rewired so all is now RCD protected. As well as the old we also have the young and people who do not have the mental capacity to see the danger, near every item we buy today has some instruction as to not being suitable for people with a reduced mental capacity.
Yet when I went to do PAT testing in a school I was shocked to see no RCD protection on most sockets, the same applies to hospitals and nursing homes they rely on the teachers, and nursing staff to ensure the people do not hurt themselves, so not read an Iphone instruction, does it state an age it is suitable for? We do tend to give vulnerable people phones, and these people often can't read small print, so they should have instructions to say where they can be used, to say you should not use it in wet conditions would mean you can't use it when it's raining which would not work, it is an out door device so should be reasonable water proof, adverts now show the phones being dropped into water and retrieved still working so we are shown by adverts suitable for use in the bathroom.
We here stories about people in USA expecting their automatic cars to do far more automaticity than they can, instead of the automation being used as a safety back up, it was used to self drive the vehicle, so I suppose a large notice only charge in doors in dry conditions is a reasonable notice to put on the phone.
Hmm, I'm off to design a shaver socket with a built in USB charging port...
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I suppose there is no real reason why you should not have a SELV socket in a bathroom? It would need to be 12 volt or less, which would fit nicely with USB. I have just read BS7671:2008 and I can't see anything to stop it, unless something added to amendment 3?
So could you fit one of these
I have no wish to play on the phone in the bath, and I am unlikely to be asked to fit one for anyone else, so not really worth looking any further, but on the surface I see no real reason why one should not be fitted in a bathroom.
When echo said what he did I was sure somebody would already have done it, but I couldn't find any, which surprised me.
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Taken from EN 61558-2-15 which BS7671 directs to for bathroom isolating transformers, the transformer should have the following construction for appropriate isolation in a bathroom environment:
This type of construction doesn't lend itself well to the flyback transformer in a SMPSU because the proximity losses are huge with that kind of winding layout. If the general EN 61558-1 standard can be followed to ensure safety I don't see why a standard USB charger shouldn't be suitable, although having taken apart a lot of these devices, I wouldn't be happy with the creepage and clearances in a humid environment.
This type of construction doesn't lend itself well to the flyback transformer in a SMPSU because the proximity losses are huge with that kind of winding layout. If the general EN 61558-1 standard can be followed to ensure safety I don't see why a standard USB charger shouldn't be suitable, although having taken apart a lot of these devices, I wouldn't be happy with the creepage and clearances in a humid environment.
Separate bobbins on different legs of the core are the best at ensuring isolation between primary and secondary. A two section bobbin is the next best provide the bobbin material will not melt if the transformer overheats. Any transformer that has its primary and secondary windings layered on top of each other will provide isolation only while the transformer is in good condition.
Many of the low cost SMPS units have a high frequency isolation transformer with it's windings inter wound on the core with only the lacquer insulation on the wire separating mains from output.
Many of the low cost SMPS units have a high frequency isolation transformer with it's windings inter wound on the core with only the lacquer insulation on the wire separating mains from output.
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You would normally see 3 windings of transformer tape as a minimum between them, but it's done this way to keep losses low.
I know it's partly jesting but -
Aren't people attempting to solve problems which don't exist to by-pass stupidity?
Perhaps we could blame the 'no sockets' rule for an extension lead being used.
Even that doesn't excuse resting it on the chest.
Aren't people attempting to solve problems which don't exist to by-pass stupidity?
Perhaps we could blame the 'no sockets' rule for an extension lead being used.
Even that doesn't excuse resting it on the chest.
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