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I accidentally damaged the MagSafe power connector on my mac, so I went looking around for a replacement cord. I found an aftermarket 85W MagSafe power adapter on e-bay that was actually cheaper than what the cords were selling for. The item description said: Why should you not use this adapter with an actual computer? Good question. It is not grounded. That means that any accidental discharge of static electricity from you to your machine while plugged into this adapter may result in ESD (Electrostatic Discharge) damage to your computer I don’t understand that. Is this saying that my computer is more vulnerable to ESD when it is plugged in to the wall than when it is running off of battery? ESD comes from me, not the wall. Besides, my MacBook comes with a two prong plug that isn’t gounded. Maybe it has to do with the internal circuitry of the power adapter. My question is, is the ebay seller correct, or can I safely use the power adapter? Thanks
Good Question! Power Cords & Plugs: Apple sells your MacBook, MacBook Pro & MacBook Air with a grounded power cord. Early systems had just a two prong cord (here in North America). Yet, you could snap off the cord and place the supplied two prong foldable plug unit onto the brick (here in North America). So you had either one connection grounded and the other not! How confusing! FYI - In other countries you may not have this as an option as local electrical codes may dictate a grounded plug is needed in all cases. Within the brick and feeding into the system via the MagSafe connector the laptop power feed is isolated via a transformer and filter circuitry. So there is no direct connection to Ground. In any case you wouldn’t want a direct path to ground as you could then be at risk of electrical shock. In fact the current buzz on the bad 3rd party iPhone chargers in China and elsewhere is likely do to a bad connection inside the charger! ESD: The scoop on ESD is as long as you don’t open your system to replace the RAM or HD your laptop is not at any more at risk being plugged in or running off the internal battery. Also using a grounded cord Vs the two prong fold down option on the brick makes no difference as well (except maybe some EMI emission). If you do open your system to add more RAM or swap-out your HD (or do any other service internally) then you should follow good ESD protection practices. While many people claim they can fix things without doing this I’ve seen the damage by not doing it, as it can cause damage that overtime can cause the device to fail.
Yes, of course it is dangerous! Here’s why: the ground wire on any laptop’s power supply serves two important functions: First, as in all grounded appliances, it prevents you from being shocked, burned, or electrocuted in the event of an internal fault. This could be from liquid getting into it, a loose wire, a broken switch or circuit board, or any number of other things. When it comes to sensitive electronics like your computer, tablet, recording equipment, etc, the ground wire protects the device from being fried in the event of a power surge or heavy static electricity buildup. You may notice that soldering irons meant for integrated circuits always have a grounded plug, but most others don’t. Even the static from your body can be enough to damage some computer parts, and the presence of a ground wire prevents any charge from getting through. Apple has stupidly made the use of the ground wire an option on their power supplies. Although the Magsafe and most other appliances will function normally with the ground disconnected, it’s a foolish and unnecessary risk to take. Remember, it is impossible to get shocked from a properly grounded appliance, and a bad power supply is a lot cheaper to replace than a fried-out laptop. The “feeling of electricity” some people report when not using a grounded power block may be an annoyance, but it means there’s something wrong. High voltages (the kind you can feel) are potentially lethal and should not be leaking into your device! It means there’s something wrong with your power supply and is exactly the kind of danger the ground wire is designed to protect you from.
You’re already grounded once through the neutral wire in any home built after about 1970. You don’t need a second ground (third wire, or prong) 99.9% of the time in any modern home, in the US anyway. I don’t know about other countries. Of course this is assuming a residential setting, commercial is another story.
Be wary of any of the folding prong plugs.When opened up and . ready to insert they are not always making a good internal connection. I saw my battery charging progress decreasing instead of increasing and realized the prongs were not making a good internal connection. Open and close the prongs several times in succession every now and then to make sure there is good internal contact or get a new plug
iPhone and many small electronics use 2 prongs (on AC side) transformer, laptops use 3 prongs. Because a laptop draws much more current than a cell phone, while cell phone can use just a on-chip transformer; the laptop needs a lumped transformer with thick wired coils and a metal frame. The metal frame needs to be grounded, not to protect the machine, but you.
Apple has a product which has been on the market for years, produces an electrical current which consumers complain about after feeling ‘shocks’ current running through their hands, and nothing changes. Let us ask this question. Do any other laptops made by other companies have such complaints? If they did, would they get away with this? I sit on a chair in Europe with 220V using a MagSafe (official Apple Store purchase) ‘grounded’ plug which is part of the extension cord (came with offical Apple Store purchase). If I have only socks on or if I am not using the rubber mat I provided for my feet to be on, I get voltage, current, shocks. And this company gets away with it.
I’m in India using a Macbook Air 2013 with original charger from Apple. If I use an ungrounded outlet (living in a rather rustic ashram) or use the 2 prong US type clip on plug in ANY outlet then I always get a mild but annoying feeling of current when touching the aluminum body of the laptop. When I use the 3 prong cable with a properly grounded outlet the problem is never there. When I travel to USA using the 2 prong clip on plug has no such problem of feeling current. I assume that is due to the 110V rather than 240V current.
Alot of the answers here seem to be based on some fundamentally incorrect assumptions. First, most modern laptop power supplies typically do not have any kind of “transformer”, they are switched-mode power supplies. A transformer is not necessary, voltage is controlled by ICs. Neither is a ground wire, typically, since there is no contiguous connection between line voltage and the DC output that powers the device. I just disassembled one of these power supplies recently: no transformer. Also, no ground, because there’s nothing to “ground”. Some power supplies do have a three-prong cord, but it’s really for perception, there’s nothing to really ground in the supply circuit itself since there is no line current present on the output side. If you’re actually getting an A/C line voltage shock, then I’d say there’s something seriously defective about the power supply, or it’s cord, because YOU are grounding that current when you touch it. Perhaps a defective circuit board is leaking some current to one side of the output.
I have a brand new MacBook pro with an Apple power supply. The supplied UK plug does not connect to the earth. As a result you can feel unpleasant electric shocks when you touch the MacBook case. I’ve measured the voltage to earth and it is 110v AC (half the mains voltage). All UK MacBooks are supplied like this and I believe that it’s wrong and it is a mistake by Apple. The UK long lead plugs have an earth but the supplied plugs that clip onto the power supply do not. I complained in the apple Store but they just offered to sell me a long lead with earth for £19.00. This should be a free product recall especially on a £3,000.00 machine. How can apple get away with this? IT’S DANGEROUS…
You can now get a grounded duckhead adapter for Macbook chargers: https://www.amazon.com/dp/B0B452LS67 It will ground the computer’s case and eliminate any buzzing sensation.
