# Plug prong holes help moulding and once secured plugs in older sockets

- URL: https://talkfuse.com/story/the-reason-most-electrical-plug-prongs-have-holes-in-them/
- Published: 2026-10-31T22:30:00+00:00
- Updated: 2026-10-31T22:47:50+00:00
- Original publisher: Engadget
- Original article: https://www.engadget.com/2300248/reason-most-electrical-plug-prongs-have-holes/
- Topics: Gadgets

## Key points

- Prong holes help position blades during manufacturing.
- Older sockets used them with retaining detents.
- Solid prongs can work in suitable sockets.

## Summary

The holes in electrical plug prongs are mainly a manufacturing aid today, helping hold the metal blades in position while plastic is moulded around them. They matter because they explain a familiar design feature that is often mistakenly thought to help modern sockets grip plugs.

The holes once worked with raised features, called detents, inside older sockets to retain plugs. Underwriters Laboratories later set requirements for sockets to hold plugs without those features, and manufacturers largely dropped the detents because they could make plugs harder to remove. Plugs with solid blades can still work in suitable sockets, while plugs with holes remain compatible with older designs; a plug that slips out may indicate a worn socket.

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Summarised by TalkFuse (https://talkfuse.com/). Quote the original publisher for the reporting and link this page for the summary and discussion.