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Comment by hecticjeff | Hacker News Reader

Maybe this is why Apple still hasn’t properly grounded it’s MacBooks, that light buzz you get is a brain boost!

What's with that? I'm constantly getting minor shocks from my Macbook, often when the inside of my forearm or wrist touches a corner of the case. I thought it was a problem with my old one, but my new one does it too.

There is also a constant light vibration when you run your fingers lightly along the body. It's quite Shocking that this is apparently "normal". None of this happens when it's running on battery.

I was honestly questioning whether there was something wrong with the wiring in my house that was causing this (after having multiple MacBooks with the same issue), because the alternative that a company of Apple’s size had such a basic issue seemed so unlikely.

You or your neighbour probably have some cheap chinese device that puts out high frequency noice on the power line.

Either you get rid of that device or you buy something like this: https://www.google.com/search?q=apple+grounded+extention+cab...

Unless you're running some serious industrial level machinery, home devices have nothing to do with power line noise. It's cause by the air around the lines and the condition of the lines themselves.

I think you are talking about another type of power line noise.

I am pretty sure a bad switch mode power supply, can push out some nasty stuff.

Given that many (most, I'd bet, by far) people don't experience this while you've experienced it on several devices, I wouldn't give up on checking out the wiring in your house.

Are you using your Macbook with an ungrounded (two prong) plug or in an ungrounded outlet ? That's the typical cause of this behaviour (or a badly-grounded outlet, which is rare, fortunately).

The shocks you observe are caused by your body slightly grounding the conductive case. They are seen with any conductive case equipment used without grounding. Fortunately, they are not dangerous on doubly-insulated equipment like Macbooks.

Don't Apple wall warts have only two prongs? It doesn't matter if the outlet is grounded if the device doesn't use the ground pin.

You can get an extension cord for Apple (computer) chargers which also carry a ground signal. Highly recommended.

https://www.apple.com/shop/product/MK122LL/A/power-adapter-e...

Typical Apple, making you pay extra for something that should come standard.

It used to be standard. I don't know why they stopped including it. Well, actually I do know - $$$

There's a large ground under the removable power plug in iPad/Mac chargers.

It can also, possibly intentionally, be used as a bottle opener.

My new Macbook is ungrounded, my old one was grounded. I experience these shocks anywhere I plug in, not just in one home/office, although some places are worse than others.

Got our kids windows laptops this christmas, and they behave exactly like this when plugged in with the included USB type-c chargers!

> There is also a constant light vibration when you run your fingers lightly along the body. It's quite Shocking that this is apparently "normal". None of this happens when it's running on battery.

I always assumed that was just because the surface has a strange microscopic pattern. I don't have one now, but I believe it only happens in one direction.

The thing I'm talking about feels like a texture but it goes both ways and disappears when its unplugged.

It's due to non-isolated converters where an EMI filter is a part of the line side using X/Y capacitors to cross over. The device isn't solidly grounded but it's also not totally floating either. There's some leakage across it.

Thank you. This seems like the only reasonable explanation I've come across after a ton of reading around.

That is not the MacBook itself, it is the power adapter not having a ground pin.

The power adapter extension cord has a ground pin, you can use the extension cord if you want to ground the computer.

Because the transformer doesn't have a metal case and once the voltage is lowered at the transformer the danger of electrical shock is reduced (as in the effects of it) so there's no reason to ground the laptop chassis.

That is probably why it is considered legal to sell the product, yes.

The high frequency buzzing you feel in your hands as you place them on the computer when the incoming power is not a proper clean sinus wave is unpleasant. Stoping that buzzing would be a good reason to ground the adapter even if it not legally required.

> The high frequency buzzing you feel in your hands as you place them on the computer when the incoming power is not a proper clean sinus wave is unpleasant.

I’ve used countless MacBooks over the years across several countries and even on square wave UPS systems. I’ve never experienced anything like this. This is literally the first time I’m hearing about this phenomenon.

The way people are talking about Apple products as having some sort of weird grounding defect in this thread is honestly kind of baffling, given that they obviously have built a product that complies with all international regulations around the world.

They don’t have a grounding defect, they are simply not grounded.

You have to purchase an extra cable with a grounding pin for your power adapter to ground a MacBook.

This is just how ungrounded devices sometimes act when you are able to come into contact with the neutral via some current path. I have LED light bulbs that are like this, you feel a vibration when touching the exposed metal heatsink of the bulb, and some bulb fixtures have started to be manufactured with a ground wire on the chassis just to eliminate that.

I'm more interested in knowing what AC power is being sent down to the laptop in the first place, regardless of the voltage.

It passes through Y capacitor that's there for EMI filtering reasons.

There is a reason to fix it as the comments are showing it, but yes it's not really for safety reason. It's annoying, a shitty user experience and makes it feel like a lower quality product. Even if it's a minor thing some users are still bothered by it but probably not enough to the companies to care.

Grounding issues on metal chassis is so strange. Creates a buzzing layer under you skin. Quite surprising the first time.

omg I thought I was the only one. Had this problem persistently when I was at a guest house in the phillipines. I figured it couldn't be safe or good for my laptop but a guy's gotta get paid...

I have that issue when charging my iPad as well

*its

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