Laptop Power Bricks and Grounding (Earthing)

[Justin]

I hope this is the right group for this question.

On my Apple MagSafe AC adapter, it can take 100 to 240v AC 50/60 cycles.
Pretty standard for laptops.
Apple's world travel kit includes ends for pretty much every country in
the world. But none appear to use grounding/earthing. I have a cord
that I use when I'm at home in the US with a three prong NEMA 5-15. On
the end that connects to the transformer/brick there are metal contacts
that contact the metal button thing on the adapter.

http://www.imagebam.com/image/cc9249124023824

in the picture above you can see the metal contacts on the three pronged
cord while the smaller travel plug has nothing but white plastic.

http://www.imagebam.com/image/039f56124023825

you can see it here and the round contact on the transformer itself.

Rather than carry around that cord, I'd rather carry just the adapter
and small plug.
I know grounding is for "safety." Safety from what? Getting
electrocuted? Static? Is there any more inherent danger to using the
ungrounded plug?

When I travel outside the US, the cord always comes with me in my
checked luggage. So if I run into an alien shaped outlet that doesn't
like Apple's design I can use my US grounded cord with a cheap little
plug adapter - of which I have plenty.

 

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These things are usually double insulated and there is nothing to
ground. I suspect the 5-15 is just to make you feel good about using
it.

I was wondering the same thing. I need a 12V 5A power brick for a box we're
building. They come in both "2-wire" and "3-wire" varieties. I verified the
3-wire sort doesn't have the output grounded, so the third wire doesn't
actually do anything. Still don't know if we need it.

 

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Does it have lower EMI?

I doubt it, but it's impossible to say without testing them, which is
scheduled for the end of the month. I'm bringing a couple, in case the one we
want to use (a three-wire) falls on its face.

Is the three wire cord easier to find than the two wire?

Both are readily available. Neither are the IEC style, though that's another
issue. I think they're called "C7" and "C8" (or "C5" and "C6", I think are
the mating ends - don't remember which is which).

What is the difference in price?

Same price, or close enough to make it moot.

Are there places that require a three wire cord for local codes?

That's the question. If so, do they ban all double-insulated gizmos?

 

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Some I've opened had a shield that was connected to the ground lead
to prevent interference to AM radios & TVs.

Hmm, maybe I'll choose the 3-wire, as the backup, then. I have three to
choose from and I think I'll have time to do the scans on two. Chamber time
comes in four-hour slots and it usually takes a couple of hours to do radiated
and conducted emissions tests.

The three conductor 'mickey mouse' ears?

Never heard them called that, but yup! That's a good description. ;-)

Then I would use the three wire units, if they pass the other tests.
If nothing else, the AC connector seems to be more rugged than the two
wire types.

That's a good point, too. Thanks. Availability is another factor. IIRC,
favoring the 2-wire (DigiKey stock). I'll have to check that, too.

Who knows? Some of those laws are passed to protect their retarded
relative's business dealings.

Agreed.

 

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You can pre test them on the bench with your scope. Some supplies
can radiate a couple volts of RF at six inches.

I doubt even they could advertise the alphabet soup certs they claim, were
that the case. ;-)

I needed some recently and had to buy them on Ebay. Less than $18
for 10 of them. I heard the term on some computer group.

They're only a couple of dollars at DigiKey.

You could use the two wire as a backup part by listing it as a
secondary component.

We can list whatever combinations we want. We're doing the listing. ;-) The
lab results are backup for the assertion of compliance.

 

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They only certified the pre-production unit.

Well... ;-)

Digikey wanted a credit card. E-bay takes paypal. It will be even
worse, if one group gets that law passed to require all debit card
transactions to be in multiples of $100.

Which group is that? Any pointers? I can't see the banks going for that one.

Very few companies can get around that. Microdyne never needed it
for their telemetry products, but their customers would have never
bought any products with problems.

It's not getting around anything (or perhaps I misunderstand you). FCC[*] is
self-certified. We've sold stuff without testing. Just don't get caught
selling an illegal radiator.

[*] It gets more difficult for the rest of the world. Some want bribes.

 

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http://money.cnn.com/2011/03/10/pf/debit_cards_limit/index.htm

Amazing! The government fucks up the economy once again.

 

[Justin]

Amazing! The government fucks up the economy once again.

Soooooo....
The consensus is that for Apple power bricks, stylish as they are, the
grounding is superficial; and it is safe for me to switch to the two
prong adapter and save some room in my backpack for two Accounting books
- namely Federal Tax and Auditing.

 

[[email protected]]

Soooooo....
The consensus is that for Apple power bricks, stylish as they are, the
grounding is superficial; and it is safe for me to switch to the two
prong adapter and save some room in my backpack for two Accounting books
- namely Federal Tax and Auditing.

Do you always make this much sense?

 

[[email protected]]

Well... ;-)

Then the bean cutters start deleting parts.

Which group is that? Any pointers? I can't see the banks going for that one.

Not the banks. I see that gfretwell already posted a link.

We can list whatever combinations we want. We're doing the listing. ;-) The
lab results are backup for the assertion of compliance.

Very few companies can get around that. Microdyne never needed it
for their telemetry products, but their customers would have never
bought any products with problems.

It's not getting around anything (or perhaps I misunderstand you). FCC[*] is
self-certified. We've sold stuff without testing. Just don't get caught
selling an illegal radiator.

At one time the FCC wouldn't let you sell RF gear without their
approval. I had a pile of product brochures from Pace for their
Landmaster radios that were stamped, 'Awaiting FCC Approval'. Since
most of Microdyne's equipment was customized for each customer, and
those customers were government agencies, they were exempt.

Our gear has radios (900 and 2400MHz) but they're certified separately and
have their own FCC IDs. We buy them with all the approvals, at least for the
US and the EU. Other countries want bribes the radio manufacturer hasn't paid
yet.

[*] It gets more difficult for the rest of the world. Some want bribes.

Or they arrest your employees and charge them with spying, like China
did to Microdyne when they were setting up an Intelsat earth station in
China.

There is that. I'm not planning a China trip. ;-)

 

[Justin]

Do you always make this much sense?

Only when I overdose on Ritalin.

 

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Only when I overdose on Ritalin.

That explains a lot.

 

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THIS POST WAS ANSWERED THOROUGHLY UPSTREAM.
YOU ARE ALL BEATING A DEAD HORSE.
YOUR GOVERNMENT CONSPIRACY MUMBO JUMBO DOESN'T HAVE YOU LOOKING VERY
BRIGHT EITHER KRACKrw

Roy Queerjano, you're not very bright (the understatement of the decade).

 

[[email protected]]

On Mar 22, 7:45 pm, "[email protected]"


YOUR DAMAGED BRAIN FAILS AS USUAL..
I AM NOT ROCKY QUEERJANO, YOU DRUG BUG.

Of course you're not Rocky Queerjano. You're *ROY* Queerjano, his even dumber
twin.

TAKE A HIKE.....YOU DIRTY LOW DOWN CONSPRACY JUNKY.

You lie, too.

 

[[email protected]]

They should have sent Roy to Japan to help pull the new power cables
into that damaged reactor.

The Saki Syndrome?