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How can I avoid my MacBook Pro giving me minor shocks?

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Re: How can I avoid my MacBook Pro giving me minor shocks?

#101

Post by zyx321 »

xenadu02 wrote: post #63
kosma wrote: post #43

Earlier quoted context omitted.

> In the US the NEC requires this. If you bother to look inside your breaker panel you will find the neutral and ground wires are literally screwed down to the same bus bar. It could be different in US, but in modern European installations the PE and N bars are separate; older installations use common PEN; and even older ones don't even have PE. Each of the wiring schemes requires different approach and poses differe…

> It could be different in US, but in modern European installations the PE and N bars are separate In the US a single PE+N wire feeds into the building. All building wiring is separated as in Europe. They are tied together in only one location, usually wherever the main switch is. Just like Europe, really old installs in the US don't have ground (PE). Some are retrofitted with ground like my house in SF. One thing pe…

In separate PE+N systems, the feeds join at a single master GFCI (typically one per distribution panel)

Re: How can I avoid my MacBook Pro giving me minor shocks?

#102

Post by derefr »

londons_explore wrote: post #97

This problem is common. You can solve it by opening up the power supply and ripping out the bright blue Y capacitor inside. It looks like a slim M&M with 2 legs. Both apple official and 3rd party power supplies will have one. Do not damage the capacitor without removing it - that could lead to an electric shock. You can remove it by cutting it off with pliers or wire cutters. The power supply will work fine afterward…

> might emit a bit of radio interference, although generally not too much

It might not cause the FCC to knock down your door, but what will it do to the laptop's own wireless and Bluetooth connectivity?

Re: How can I avoid my MacBook Pro giving me minor shocks?

#103

Post by phee »

stouset wrote: post #79
jordwest wrote: post #18

What's fascinating to me about this phenomenon is that you can actually feel the 60Hz AC by running your hand across the lid. It feels as if the surface is slightly bumpy, but the width of the bumps changes as you adjust the speed your finger moves. Unplug from mains, and the surface becomes smooth. As the answer notes, this only happens when using the two-prong adapter without earthing. It also seems to be more noti…

I'm deeply curious about this! Is it possible to recreate the situation at home, or does this require something miswired with the mains power supply or power adapter, or an older MacBook Pro?

connect the two prong adapter, take your shoes and socks off, feet on the ground... feel the vibe! the best shocks you get at the edges or at the pointy edges in that groove to lift the display up.

Re: How can I avoid my MacBook Pro giving me minor shocks?

#104

Post by LaurentVB »

Too wrote: post #96
Teever wrote: post #88

Earlier quoted context omitted.

What? That's crazy looking! Why not just put the third prong in there if it's wired up to handle a screw? What's the point?

Just guessing here but I think it's to allow easy grounding of old appliances and other equipment that might risk contact with electricity but are not grounded by default. Metal frame desk as example.

Very clever actually.

Re: How can I avoid my MacBook Pro giving me minor shocks?

#105

Post by ti32x »

Also worth noting: some of the cheap knockoff magsafe adaptors available on ebay have an earthing "pin" inside the adaptor (the mushroom thing) which is actually just coated in a metallic coloured covering/paint.

This doesn't actually provide contact to the existing ground pin, so you have this issue.

Re: How can I avoid my MacBook Pro giving me minor shocks?

#107

Post by creshal »

Hydraulix989 wrote: post #87
sduff wrote: post #83

Earlier quoted context omitted.

Why would you still buy from the same manufacturer that denied bad (and potentially deadly) design?

Like I said, it was otherwise, an excellent vacuum. Any how, I know about Lenovo's Superfish and recently its attempts to block Linux installs, but I am still a die-hard Thinkpad user because these are very large organizations where all it takes is one single person's oversight to cause a mistake.

They didn't "attempt to block Linux", they just shipped hardware without a Linux driver.

And later released a workaround to make the hardware work in a slower, more power consuming backwards compatibility mode so Intel can continue not properly supporting the hardware in Linux.

But sure, it was totally "Lenovo blocking Linux".

Re: How can I avoid my MacBook Pro giving me minor shocks?

#109

Post by cr3ative »

londons_explore wrote: post #97

This problem is common. You can solve it by opening up the power supply and ripping out the bright blue Y capacitor inside. It looks like a slim M&M with 2 legs. Both apple official and 3rd party power supplies will have one. Do not damage the capacitor without removing it - that could lead to an electric shock. You can remove it by cutting it off with pliers or wire cutters. The power supply will work fine afterward…

Care to explain what this does?

Re: How can I avoid my MacBook Pro giving me minor shocks?

#110

Post by Animats »

Doesn't anybody have a DVM around? If you can feel a stray voltage, measure it, and find the source.

As someone else pointed out, get an outlet tester.[1] They're about $7. You may have an open ground, or reversed hot/neutral. Once you've eliminated that, suspect the power supply.

Make sure you have a UL-listed power supply. If you're getting stray AC voltage on the output side of a UL-listed supply, report it to UL. Here's the form.[2] There's no excuse for that.

[1] https://www.amazon.com/Amprobe-ST-101B-Socket-Tester/dp/B008... [2] http://www.ul.com/customer-resources/market-surveillance-dep...

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