Nor does my Lenovo one.
I get the feeling that Monkeh DGAS about any of that.
Might a power supply designed to use an earth connection emit more RF than the law allows? Would any certification of RFI compliance be nullified?
Unearthed adapters
- Thread starter ccam108
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Might a power supply designed to use an earth connection emit more RF than the law allows? Would any certification of RFI compliance be nullified?
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I happened to notice a bright yellow warning label next to the plug on a Dell laptop supply today. It shows a picture of a 3 pin plug, a socket (or adapter), and some text. One side has a foreign plug and (I assume) Chinese text; the other side shows a BS1363 plug and English text. The text says :
[n]WARNING[/b]: Be sure to insert the grounding pin (1) of power cord into grounding contact (earth symbol) of the electrical outlet or power strip. Improper insertion can result in electric shock, fire, or damage to your computer.
As it happens, this particular supply has an oddball connector rather than the more common 5A cloverleaf, the internals are unlikely to be significantly different to the rest of their supplies.
Personally, I think the warning is a tad OTT (fire ?), but clearly Dell believes that this supply should be earthed to be safe.
[n]WARNING[/b]: Be sure to insert the grounding pin (1) of power cord into grounding contact (earth symbol) of the electrical outlet or power strip. Improper insertion can result in electric shock, fire, or damage to your computer.
As it happens, this particular supply has an oddball connector rather than the more common 5A cloverleaf, the internals are unlikely to be significantly different to the rest of their supplies.
Personally, I think the warning is a tad OTT (fire ?), but clearly Dell believes that this supply should be earthed to be safe.
Just looking at the two I've got here:
Toshiba (with cloverleaf inlet) is not double-insulated.
Macbook (with figure-8 and odd earthing contact) is double-insulated.
The Macbook supply is the most interesting, as it came with two leads/adapters:
The corded one had an earth contact, but the adapter block doesn't for some strange reason.
Toshiba (with cloverleaf inlet) is not double-insulated.
Macbook (with figure-8 and odd earthing contact) is double-insulated.
The Macbook supply is the most interesting, as it came with two leads/adapters:
The corded one had an earth contact, but the adapter block doesn't for some strange reason.
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Yes, that is interesting - I generally use the cord with earth contact.
Also of interest, when I'm plugging in the speakers, if I touch the contacts on the jack plug and touch the case of the MacBook Pro then there's "quite a hum".
And at some point, I noticed I was getting what felt a bit like touching hot metal where my hands rested on the palm rest - I then realised it was an electrical "tingling" when I was using the unearthed "duckhead*" adapter.
I've just done a quick check - done it before but forgot the result.
With earthed lead, 0.0<something>V AC between computer case and case of another one on the same socket - tiny but still enough to create hum on amplified speakers. With duckhead, about 77V AC
Having been inside a couple of Apple PSUs (to repair cables and so on), I'm not surprised. There's a metal screen around the PSU connected to that non-standard earth 'button', and I can't remember whether the output negative is connected to it.EDIT: Just checked. There's about 1kΩ between earth button and output. And there's no double-insulated symbol.
I have been tempted to pop into the Apple Store some time I'm in Manchester, with a voltmeter, and ask how having a case at 77V AC complies with safety regs ? OK, the available current is tiny, but isn't there a voltage limit for exposed metalwork ?
Mind you, the way Apple behave, they'd probably claim it's a patented feature
* That's what they appear to call them in the US - the two prongs of their adapter look a bit like the bill of a duck, with the adapter as the ducks head.
I've had that before, it gradually got worse from being a small tingle to the point where it was uncomfortable verging on painful. Now I only ever use the earthed lead and not the duckhead. It's also subconsciously changed the way I type on it
Seems they haven't solved the issue with the newest MBP
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why do apple feel the need to redesign things that have worked perfectly well for years? this is why I dont buy apple products
Because of the need to be "revolutionary", not that I'd call (for example) "higher res screen" a revolution, more an evolution
But in many cases it's ... drum roll ... about money !
Keep changing the ports, and charge punters again for more adapters.
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always looks like overpriced tat for gullible people.
at a time everyone wants standardisation, apple make things that are designed not to work with other things
at a time everyone wants standardisation, apple make things that are designed not to work with other things
I too have noticed the tingling from Apple products. Not so much with my own Macbook but mainly in the store I would feel a vibration under my fingers if I lightly touched one of the aluminium-cased models.
There is definitely a DI symbol on the 60W charger I've got from a few months ago. It's not obvious - it's very near the top-left of all the writing on the bottom.
There is definitely a DI symbol on the 60W charger I've got from a few months ago. It's not obvious - it's very near the top-left of all the writing on the bottom.
Mine too, it's about the size of a grain of sand
Neither company replied.
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