What are the holes in the pins of electrical plugs for?

The electrical outlets we use every day typically have two small holes in the metal prongs . These holes, which may go unnoticed by many, are not there by chance. They serve a practical purpose related to the safety and efficiency of electrical contact , and their presence is especially common in type A and B plugs , common in countries like the United States and Canada.

The main purpose of these holes is to ensure a better fit within the outlet. Many plugs and sockets are designed with tabs or springs that fit into these holes , ensuring the plug doesn't easily come out, preventing accidental disconnections. This is especially useful for devices that remain plugged in for long periods or are subject to frequent movement.

In addition to improving grip, these holes can also be used during the manufacturing process . Some machines that assemble or inspect plugs use these holes as reference points for aligning or manipulating the pins during production or packaging. They have also been reported to allow the insertion of locking devices , for example in industrial or educational settings where unauthorized use of certain electrical appliances is desired.

Another interesting, though less common today, use is its role in the design of plugs with safety mechanisms . Some older plug models included mechanisms that prevented the flow of current if these holes were not detected, helping to prevent the use of inappropriate metal objects in the outlet.

When connecting a plug, make sure it fits smoothly and without forcing it. If you notice any wiggle or looseness, the outlet may be worn or damaged, which could cause poor electrical contact or even overheating. In this case, it's best to replace the plug or contact an electrician.

Avoid handling electrical plugs or sockets with wet or damp hands , and never insert foreign objects into socket holes. Although they may seem harmless, these tiny holes are an integral part of a system designed to operate safely and accurately.