MacBook current leakage - vibration/tingling sensation

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Batman

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#324456 12-Apr-2026 18:44

I keep my MacBook plugged in when using it on the desk, set to 80%, to stop it from having too many discharge cycles.

After a while i will experience current leakage in the form of tingling and vibration sensation.

Internet says I need a 3 pin plug. But the plug that Apple provides is only 2 pins ...

Is this constant shocking a bad thing and should I just unplug it and accept the charge cycles?

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#3480263 12-Apr-2026 18:47

This has been a "thing" for at least two decades. You can get a 3-pin cord that connects to the existing power brick. There's a thing that it slides into that looks like it's just an alignment guide, but it's actually the ground pin.

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#3480274 12-Apr-2026 20:46

https://www.apple.com/nz/shop/product/mw2n3x/a/power-adapter-extension-cable

cddt

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#3480275 12-Apr-2026 21:06

My wife's Mac does this too, I hate the sensation.

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#3480284 12-Apr-2026 21:58

Aaron2222:

https://www.apple.com/nz/shop/product/mw2n3x/a/power-adapter-extension-cable

i see. pay $39 to not get gently electrocuted ... thanks.

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#3480311 13-Apr-2026 08:25

I hate this so much.

cddt

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#3480347 13-Apr-2026 10:05

Any cheaper options?

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#3480350 13-Apr-2026 10:16

That's just the power of Apple Silicon!

jamesrt

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#3480370 13-Apr-2026 11:15

You could TRY going down the CGA route and suggesting to Apple that being continuously electrocuted by their product perhaps suggests it's not "fit for purpose".

I don't like your chances, however.

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#3480372 13-Apr-2026 11:21

Normal, I'm told. Used to experience this with an Intel MacBook Pro, but never faced the issue with the Intel-era MacBook nor an M-series MacBook Air. It must be something specific to the MBP.

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#3480373 13-Apr-2026 11:22

jamesrt:

You could TRY going down the CGA route and suggesting to Apple that being continuously electrocuted by their product perhaps suggests it's not "fit for purpose".

I don't like your chances, however.

I'd suggest the chances are nearly 100% he would win that battle. Apple would send him a replacement cable long before they had to front a disputes tribunal hearing. Problem is the fee is as much as the cable so /me shrugs

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#3480375 13-Apr-2026 11:30

This is an utterly fascinating phenomenon I came across at work and even the owner of the business wasn't aware of it so we got in the electrician who'd never heard of it and they spent days testing this, testing that and basically it is 'as designed' and not a fault per se, but explicitly allowed by our with compliance and regulations. He'd been a leccy for 25 years and never heard of it/come across it.

So it's not a fault, but a universal experience you will encounter in practically every house across New Zealand.

You can test it yourself:

Plug in a 2-pronged AC to USB adaptor into the power socket.
And a 3-pronged AC to DC adaptor into neighbouring power socket.

You can measure 115V AC at up to 0-1amp*(!!) when bridging the two cable shields with a multimeter.

I measured this consistently across:
2x apple USBC adaptors, 1x 20W, 1x 140W for the unearthed adaptors.
2x AC to DC adaptors, 1x 135W and 1x 230W for the earthed adaptors.
2x USB C-C cables from the Apple adaptors.

This is what you're experiencing and why it tingles.

Would love an explanation but for now it's just 'one of those' modern mysteries.

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#3480376 13-Apr-2026 11:34

jamesrt:

You could TRY going down the CGA route and suggesting to Apple that being continuously electrocuted by their product perhaps suggests it's not "fit for purpose".

I don't like your chances, however.

Considering it's not a safety hazard (just annoying), and Apple are far from the only ones with this problem, I'd say your chances are approximately zero.

Your other option is to look for a 3rd-party grounded USB-C adapter, though that's not a guarantee either (I've used one that still had a bit of a tingle). And yes, it is stupid that Apple doesn't just provide grounded duckhead plugs.

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#3480381 13-Apr-2026 12:00

I experience the same tingling and vibrating feeling when I use my Microsoft Surface Pro4 with the 2 prong power adapter.
Just lived with this as I dont use it when its being charged.

Must try the 3 prong larger adapter and see if I get the same effect. ( Assume the earth pin will make this leak disappear)

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#3480390 13-Apr-2026 12:06

I notice it if I bridge the gap, with my hand between my Mac and my work laptop.

The little things make the biggest difference.

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#3480392 13-Apr-2026 12:14

I am not a sparky, however I believe that this is an issue across any and all switch mode power supplies that have only a phase and neutral connection on the mains input side, rectify mains voltage directly ahead of converting it to a lower DC output voltage, have no internal isolation and no proper earth connection to the power supply's chassis.

The output, despite being low voltage, is "floating" above mains earth as the low voltage negative connection is neither bonded nor referenced to mains earth, and thus there is a small (leakage?) current that we humans feel as a tingle when we touch any metal parts on the device being powered.

I have felt this when touching the antenna cable for TV's with said non-earthed switch mode power supplies. Powering the TV via a mains isolation transformer removes the problem, as the mains input is then isolated from ground, so no "tingle" is felt. I used to have a National Quintrix TV that had a live chassis with no earth connection. Both sides of the coaxial antenna cable were capacitively coupled to the chassis, but it was still possible to get a painful but relatively harmless zap when touching the antenna cable when the TV was on.

A TV installer told me that back in the old days when TV's had linear power supplies with a mains transformer that effectively isolated the low voltage side from the mains, and the chassis was grounded, the chance of a shock or tingle was low, whereas as newer TV's with switch mode power supplies came along, it was vital to ensure the TV was powered OFF and ideally the antenna cable disconnected before they climbed a ladder to have a look at an antenna, lest they touch it and get a shock off it while the TV was off and in standby mode.

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