Have you ever taken a close look at a European-style plug and noticed the small holes in its prongs? At first glance, they might seem useless — but they actually have an interesting backstory tied to electrical safety.
Picture this: you’re using an appliance like a washing machine, and suddenly you feel a jolt of electricity. What happened? Often, this kind of shock comes from a damaged internal wire that makes the appliance’s outer body live with electric current. To prevent accidents like these, engineers came up with an essential safety feature — grounding.
Grounding is the third connection point (besides live and neutral) that channels any stray current away from you and safely into the ground. If something inside the appliance malfunctions, the electricity follows this path instead of shocking you.
So, where do the holes come in?
In some European countries — like France — wall sockets are designed with a protruding grounding pin in the center. Plugs used in these systems have holes in the prongs to accommodate this pin. Here’s why it matters:
The grounding pin connects before the live and neutral pins when you insert the plug.
That way, the appliance is grounded before it’s powered — adding a crucial layer of safety.
Now let’s take Germany, for example. Their outlets don’t use a central grounding pin. Instead, the sockets have metal clips on the sides. Corresponding plugs feature side contacts that align with these clips. This setup does two things:
If the device develops a fault, any dangerous current is diverted through the side clips.
And if the plug gets pulled out, the live connection breaks first, while the ground disconnects last — again, making the process safer.
In some other places, including older or more basic systems, there are no pins or clips at all. So why do plugs still have holes?
Those holes are just leftover design features based on the broader European plug standards — a nod to compatibility, even if the local socket doesn’t take full advantage of them.
Have you ever noticed these holes before? Let us know what you thought they were for!
