Yeah this is just a static buildup on the surface of the metal enclosure. Completely normal and will happen with any metal product, if you look at any electrical cable you'll notice a metal shield around it (USB-C for instance), this is the grounding plate. On a MBP, this connects straight to the case, and by extension yourself. All you're feeling is a few electrons building up a positive charge which gives a tingling or vibration sense when touched. Absolutely not an electric shock, you'd know if was. Also not a static shock (Which can still be fatal).
The 3pin plug directly attached to the power brick is not grounded, in-fact most UK electrical products do not make use of the ground pin. This is because most countries in the world do not make use of ground, so anything imported usually just has a dummy ground pin. In the case of alleviating this however, you can use the extension cable. This provides greater surface area for the electrons to spread along meaning there are fewer building up on the case and exhibiting this phenomena.
If you are at all concerned, there is no electrical connection between the charging circuit and the case. + - connections are made inside, the ground is there purely to remove the stray electrons that build up. It's just physics really, if you rub two surfaces together at speed it creates friction, which creates small amounts of static electricity. In this case fast moving electrons passing by a static object is the same thing.
Don't worry, use an extension cable. There is no such thing as an extension cable with a ground pin, as the charging circuit itself does not have this connection, so there are no wires to connect to ground or anything externally. I'm sure you could find one online that has a metal pin in place, but it won't actually be connected to anything. Note the part that connects to the power bring only accepts 2 terminals...
The 3pin plug directly attached to the power brick is not grounded, in-fact most UK electrical products do not make use of the ground pin. This is because most countries in the world do not make use of ground, so anything imported usually just has a dummy ground pin. In the case of alleviating this however, you can use the extension cable. This provides greater surface area for the electrons to spread along meaning there are fewer building up on the case and exhibiting this phenomena.
If you are at all concerned, there is no electrical connection between the charging circuit and the case. + - connections are made inside, the ground is there purely to remove the stray electrons that build up. It's just physics really, if you rub two surfaces together at speed it creates friction, which creates small amounts of static electricity. In this case fast moving electrons passing by a static object is the same thing.
Don't worry, use an extension cable. There is no such thing as an extension cable with a ground pin, as the charging circuit itself does not have this connection, so there are no wires to connect to ground or anything externally. I'm sure you could find one online that has a metal pin in place, but it won't actually be connected to anything. Note the part that connects to the power bring only accepts 2 terminals...
