Why does my laptop give me small but sometimes painful zaps? Are they dangerous?

Feeling tiny zaps or a buzzing feeling while using your MacBook or another metal-bodied laptop? You’re not alone.

Do you get tiny electric zaps from your laptop when using it? Do you feel a strange buzzing feeling when touching the metal case?

If the answer is yes, then your next logical questions are likely to be "what's causing this?" and "is it dangerous?"

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I've been getting these tiny shocks from metal-bodied laptops for years. When I first felt them, I was understandably distressed, but while they are uncomfortable, they're not dangerous, and there are things that you can do to reduce the problem.

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So, what's causing the problem?

Put in simple terms, what you're feeling is a slight electrical discharge coming from the power supply, traveling along the cable, and grounding through the case. It's a tiny amount of current -- in the microamps range -- and not harmful or dangerous in any way.

It's just a thing that switched-mode power supplies do. 

To throw more variables into the mix, first off, not all chargers do it. Oddly, the way Apple has built radio frequency (RF) noise suppression into their chargers appears to make them more susceptible to delivering zaps.

The zaps can vary too. Sometimes you don't feel them, sometimes they're tingles, other times they feel quite nasty.

And there are loads of other variables.

For example, the surface the laptop is on, what you are on, where on your body the laptop makes contact (the skin is thin on the underside of the arms and wrists, and back of your hands, so you feel the zaps here more than, say, your hands), and how much of your body makes contact with the metal body (small contact areas concentrate the zap).

Different laptops are also a factor. Personally, I find MacBooks and MacBook Pros to be the worst. Different chargers are another factor.

Weather also makes a difference, with warm, dry air making the problem worse because the charge can't dissipate so easily and your skin sweats more, so there's better conduction.

Also, if you're someone who drives a laptop in a t-shirt, you're more likely to feel the tingles and zaps than someone who wears long sleeves.

And some people just don't feel this at all.

I've seen all sorts of solutions to this. In the US, UK, and EU, you could use an earthed adapter for MacBooks. For other chargers and other countries, this becomes more complicated, and you might have to consult an electrician for help.

I've also seen people put a thin plastic film on the metal parts of their laptops to insulate them.

Or you could just not use the laptop when it's plugged in. Not the best solution, but it works.

Have you been affected by this problem? Do you have a solution or tip, or do you just live with it? Let me know!

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