Electric shock/mild vibrating sensation on MacBook Pro when charging

Every time I plug my MagSafe 2 power supply into an power outlet, this Mac's aluminum body gives me a mild vibrating sensation and sometimes an electric shock. After searching for info about my problem on many forums, they believe there's some problem with my grounding.

My country's electricity is about 220v. If I plug it into a 110v power outlet should it solve the problem?

I'm not an electrician so I don't really know what to do.

Solution 1:

I've had this problem with a 2005 Powerbook, 2008 Macbook Pro, and 2010 Macbook Pro. Every Mac I've owned, in other words.

Macbooks come with a selection of two plugs for the adapter. One of them is an ungrounded plug ("AC wall plug"). From tech specs, In the Box:

MagSafe 2 Power Adapter, AC wall plug, and power cord

This, coupled with the metal enclosure, means you get a tingling sensation. You provide the earthing.

Use the grounded power cord instead, even if it's inconvenient.

Solution 2:

This is known as "current leakage", and is usually caused by the device being grounded differently than your body is. Or the device being grounded differently than the metal desk, and your hand is the conductor between the device and the desk. See the Wikipedia entry for ground loop.

The voltage differential between the two grounding levels causes a little current to flow from one to the other. It's usually not a safety issue, but it is an annoyance.

This is basically the same thing as the "60 cycle hum" or "ground loop hum" you get on A/V equipment if one of your devices is grounded differently than another, and you're using an analog audio connection between them; the difference in ground levels causes current to flow from one box to the other over the analog audio connection, which sounds like a buzz at 60Hz, because 60Hz is the frequency at which Alternating Current alternates. (It may be 50Hz in your country.)

In some countries (US and possibly others), the AC connector that connects directly to your MacBook Pro's power brick is ungrounded, but the AC power cord is grounded. If you're using an ungrounded connection, switch to a grounded connection. Or vice-versa. See if it makes a difference. If trying out a grounded connection, make sure you have a proper working ground on the outlet you're connecting your power adapter to.

You basically want your MBP and everything else you or it could make a circuit with to be grounded the same way. If you have a metal desk that isn't grounded, consider getting a grounding cord for it as well.

Looking up resources for resolving ground loop problems in audio equipment may give you additional tips and suggestions for how to resolve this.

If that doesn't solve it, call Apple tech support and find out what your options are.