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schalliol

macrumors regular
Original poster
May 7, 2002
229
50
Carmel, IN
Hi Everyone, I've noticed the tingling feeling many have reported when using my MacBook Pro, and I've read that this is because the power adapter isn't grounded. I do have the longer cable, but where I'm plugging it in, I really just want something that's compact. Is anyone aware of a US grounded not long snap on plug or cable? Thanks!
 
Even if you put a three prong cable onto the adapter, it won't be grounded because there is no ground on the adapter.
 
The adapter itself is grounded.
That's what this metal ring is for.

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But the short plug that comes with the adapter has no grounding. Even though it has 3 prongs for the US models because it's not connected internally. The extension cable you can buy from Apple has that.
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You can check that if you look inside the rail of the plug. if there's no metal contact inside the rail, then the grounding pin is not connected and is just to hold the plug in the socket.
 
Thanks. Yes, this is why I’m looking for a short way to ground it for U.S. use. Does anyone know of a way to do that in the USA except with the long Apple cable?
 
If you want to do some MacGyver-ing, you could go out and purchase a 3 pronged replacement male plug like this male plug then cut your Apple cable to the desired length, then attach the male grounded plug. It may not look as elegant as the standard cable (especially since the white colored version seems to be not stocked locally) but you won't get that tingly feeling.

I wonder if the problem is that there is a short inside your MacBook Pro. Products aren't designed to require a ground to function properly. The fact that the tingling sensation is present with the snap on 2 prong plug but not with the grounded cable means that there is a failure in insulation in the circuitry within your MacBook pro. There could be a wire or small cable with frayed insulation making contact with the metal case.

Putting the device on an AC adapter with a 3 pronged cable just removes one of the symptoms of the problem, but does not cure the problem. It would be good to figure out the underlying problem rather than mask it.
 
I wonder if the problem is that there is a short inside your MacBook Pro. Products aren't designed to require a ground to function properly. The fact that the tingling sensation is present with the snap on 2 prong plug but not with the grounded cable means that there is a failure in insulation in the circuitry within your MacBook pro. There could be a wire or small cable with frayed insulation making contact with the metal case.
No offense but you're on the wrong track.

In home wiring, current flows on both hot and neutral. Thus, it is common to have a non-zero voltage on the neutral wire due to internal resistance on the way back to the panel.

Thus when a device is connected just to two prongs (Hot & Neutral), it can float at a slight voltage relative to ground. Sometimes enough to give a slight tingle.

Adding a ground connection avoid that.
 
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In the US the neutral wire and the ground wire connect to the same bus in the breaker box. You might try reversing the plug to see if that cures the problem. Do you get that tingling sensation anywhere else? If so, you should have the house grounding system checked. There could be a break or high resistance between the breaker box ground connection and actual earth ground allowing another circuit to back feed into your outlet. This is potentially dangerous.
 
I think the issue might actually be one of static electricity that needs somewhere to go. I've looked up this issue and found it's really common. The Power Adapter can handle this but it just needs a ground. The issue is that the Apple power adapter connection is unusual. If someone has a three pronged US plug attachment, that's all I really need. It's probably not worth it to MacGyver a full new cable, but I did think about simply adding a ground wire to the metal ring. That's not ideal, but that might be the only option.
 
I think the issue might actually be one of static electricity that needs somewhere to go. I've looked up this issue and found it's really common. The Power Adapter can handle this but it just needs a ground. The issue is that the Apple power adapter connection is unusual. If someone has a three pronged US plug attachment, that's all I really need. It's probably not worth it to MacGyver a full new cable, but I did think about simply adding a ground wire to the metal ring. That's not ideal, but that might be the only option.
Are you feeling tingling or a shock? If it is indeed STATIC electricity one would expect a shock like when one contacts an object on a dry day and the built up charge is discharged. The tingling is due to leakage current--does a dc current leak cause a tingling sensation or is it only ac current leak that causes it?

Can you feel the tingling when on battery only? Does the tingling go away with the 3 pronged cord attached to the power adapter?

If you don't feel tingling when on battery power or with the 3 pronged power cord attached, could the problem actually be with the power adapter? Did you notice the tingling when the MBP was brand new or with a different power adapter?

If you don't want to shorten the power cord, you could always loop 4-5 feet of the cord and velcro or rubber band the loops so you only have a 1-2 foot long snake from the wall to the power adapter.
 
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No offense but you're on the wrong track.

In home wiring, current flows on both hot and neutral. Thus, it is common to have a non-zero voltage on the neutral wire due to internal resistance on the way back to the panel.

Thus when a device is connected just to two prongs (Hot & Neutral), it can float at a slight voltage relative to ground. Sometimes enough to give a slight tingle.

Adding a ground connection avoid that.
No offense taken, my user ID is self explanatory. I am wondering since the OP is feeling tingling when touching the MBP and the MBP should be getting DC power from the power adapter and runs on DC power, what is the source of the tingling sensation. The wall adapter does function from 110-220 AC, but is there a variation in the output side? Is the tingling due to dc or ac current leakage?
 
It’s a really good set of questions. I don’t know if it’s leakage or static, but if I’m wearing headphones plugged into a USB amp and am sitting with a blanket I can get crazy sounds if I move a lot. I think grounding would be a good idea regardless. Maybe if I can find a good way to ground, we’ll be able to tell what it is. Hmm...
 
It’s a really good set of questions. I don’t know if it’s leakage or static, but if I’m wearing headphones plugged into a USB amp and am sitting with a blanket I can get crazy sounds if I move a lot. I think grounding would be a good idea regardless. Maybe if I can find a good way to ground, we’ll be able to tell what it is. Hmm...
All macs (and also USB-C iPads) have this tingling feeling when touching them and they're not grounded properly. It's due to current leakage (not sure whether AC or DC though).

Since 2016, Apple doesn't ship the extension cored (which has proper grounding) with Macs but only the short plug that is not grounded in most countries.

Using the extension cord, or a Thunderbolt 3 dock with power delivery that is properly grounded, will eliminate that feeling.

AFAIK, that current leakage is not dangerous, but it's annoying to most people.
 
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Has anyone seen a grounded clip on plug for US power? I’m kind of amazed the only way is with the long cable. Maybe third-party?
 
No answer to OP's question, but on my desk I use the grounded cord and no tingling, when I'm travelling (remember that?) I use a 29W Apple USB-C charger and I always get the tinglies. It's quite bad that Apple quit shipping that extension cord with a ground connection with their laptops. That cable and plug was a neat solution to the problems and different use cases with portability, cable length and of course, grounding.
 
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Has anyone seen a grounded clip on plug for US power? I’m kind of amazed the only way is with the long cable. Maybe third-party?
Haven't found one, and I also will get the same thing with a non-Apple two-prong USBC power source.

Only ever notice it if I'm also touching something that is properly grounded, so it's never really been an issue for me.

It'd be pretty simple and inexpensive to just trim the Apple extension cord and put a new plug on. Pay attention to hot/neutral wires though.
 
OP:

If you want to be "grounded", use the long cable that Apple provides for that.

It's that simple.
(nothing follows...)
 
OP:

If you want to be "grounded", use the long cable that Apple provides for that.

It's that simple.
(nothing follows...)
Read the first post. I know you can do it with the long cable, I'm searching for a short way to do that per the title. For reference, I have this power adapter in a floor box, and it's just too full to put the long cable in.
 
Read the first post. I know you can do it with the long cable, I'm searching for a short way to do that per the title. For reference, I have this power adapter in a floor box, and it's just too full to put the long cable in.

Clip the long cable to length and put this on the end of the wire. Done.

 
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