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Power cord for MacBook Pro

Posted on 2011-03-10
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Last Modified: 2012-05-11
I want to get another power cord for my MacBook pro.
The original is a 85W MagSafe Power Adapter, A1290.
I'm looking at reconditioned ones or clones since they are considerably cheaper.

2 questions:

They have 2 conductor plugs. My original has 3 conductor. Is the ground necessary?

The clone does not list A1290 in the compatible model numbers. They are both 85W, though, so they are compatible?

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Question by:allelopath
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6 Comments
 
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by:
dlethe earned 334 total points
ID: 35103915
An aluminum MBP is probably the worst computer on the planet NOT to be grounded.  The ground wire protects it from damage by static electricity. The entire case is a conductor.  Surely you are quite familiar with the shock you get after walking away and touching the macbook.   The ground wire spares the hard drive & motherboard this unpleasant experience.

Buy what you need to protect the system.  It is a worthwhile investment.
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LVL 47

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by:dlethe
dlethe earned 334 total points
ID: 35104084
Note also that grounding reduces RFI so your airport might not work as well, or other items in your location might get poor performance;  it is technically a risk of fire (If your house burns down and the macbook is the 'epicenter', then you will have an unpleasant conversation with your insurance company .. they might not have to pay due to your negligence)

You could even fry it by pugging in a connector like network cable or ethernet; or even opening it up to stick in a DVD.  Now is this a sure thing going to happen?  No, but is the risk enough for concern? Absolutely.  If I had a nonconductive notebook case, then personally I wouldn't worry about it, but if you have the aluminum unibody .. then risk is too high to just ignore it.
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Assisted Solution

by:mccrick
mccrick earned 166 total points
ID: 35105076
You absolutely do not need the three prongs if you MBP is built correctly. The ground is there for your safety primarily, so that you don't get shocked or electrocuted. Apple provide a two prong adaptor (with no ground) with every low voltage device they sell, computers, ipods, phones, etc. The cheaper knock-off is usually the way to go.

It doesn't really reduce the risk that your computer would start a fire. Just because a computer burns down your house, doesn't mean an insurance company won't pay your claim. If someone made the argument that the cheaper model was more likely to start a fire due to lower build quality or design, I might believe that.

See links here on MacBook Pros and electric shock, or google MacBook Pro electric shock to see what others have experienced.

http://forums.macrumors.com/showthread.php?t=409747

http://discussions.apple.com/thread.jspa?threadID=1229402

If you ever get shocks from your computer, I'm pretty sure that Apple would extend their warranty to fix it. They don't always do right by their customers, but I have found there products to be safe and I have seen them extend warranties to take care of safety issues. I'm not sure what they are doing about these "little tingles some people have experienced.

Bottom line: Cheap product should be compatible. But you are taking a small chance that you would have a very annoying problem on your hand, literally.

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Expert Comment

by:dlethe
ID: 35105923
If we are judging the answer by blog posts then here is one where people report fires when they lost the ground.
http://www.tampaforums.com/forums/free-4-all/no-neutral-ground-bad-125191/

You can find all sorts of posts from people who had fires via google.

But don't take my word for it.   Call somebody at your local fire station if you think it is safe.  Call any licensed electrician.  As for insurance, call your insurance agent and ask them if it is OK to do what you want to do, and are you going to be covered in case of a fire.  (Well, don't actually -- your rates might go up just by asking this question).

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Author Comment

by:allelopath
ID: 35109729
I don't not experience any shocks with my MBP
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LVL 47

Expert Comment

by:dlethe
ID: 35109905
"I don't not experience any shocks with my MBP"

And if you talk to a fireman or electrician, you will also find that the owners of the pile of smoking debris that was once their house said similar things about the electric drill, PC, whatever, in situations where fires were determined to have been caused by improperly grounded small appliances.

Bottom line, grounding is there to prevent shocks & fires when things fail.  Is it low risk?  Certainly.  Is it worth spending the money to do it right?  I bet your local fire chief can hook you up with somebody who learned the correct answer to the question the hard way.

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