What are they named and what is their function?

[Norm]

Ever notice the punched holes in the prongs of electrical plugs? Do these holes have a proper name? Why are they there and what are they supposed to do if anything?

NORM SAGE

[Jim Morrison]

Norm,

Their official name is called the Katen Kut-out. They were invented by our own Jim Katen, but he named them after his wife, Mrs. Katen.

I'll let him tell you what they're for.

[Les]

I thought they were peep sights.

[chrisprickett]

Originally posted by Norm

Ever notice the punched holes in the prongs of electrical plugs? Do these holes have a proper name? Why are they there and what are they supposed to do if anything?

NORM SAGE

There are several reasons:

Those holes mate with bumps inside the receptacle that keeps the plug from falling out and also improve the contact points. Some plugs just have spring action blades that serve the same purpose.

There are also some special outlets which allow you to lock the cord into the socket, by putting rods through the holes. This way, for example vending machines cannot be easiliy unplugged. Electrical devices can also be "factory-sealed" by the manufacturer using a plastic tie or a small padlock through one or both of the plug prong holes. A manufacturer might apply a plastic band through the hole and attach it to a tag that says: "You must do X or Y before plugging in this device". The user cannot plug in the device without removing the tag, so the user is sure to see the tag.

I'll be danged if I know what the holes are called.

[paul burrell]

I think a hole is called a hole [:-graduat.

[kurt]

Chris, that's interesting stuff. I had no idea.

[Jim Katen]

Originally posted by Jim Morrison

Norm,

Their official name is called the Katen Kut-out. They were invented by our own Jim Katen, but he named them after his wife, Mrs. Katen.

I'll let him tell you what they're for.

My understanding is that, at one time, long ago, the female had a little nub. When the male prong was inserted into the female slot, it contacted the female nub in such a way as to make for a strong, durable connection. Nowadays, however, the nub is not to be found and, so, the male prong hardly ever contacts it. Instead, the female relies on continuous and unrelenting pressure to keep the male in its place. The design of the male prong is, therefore, largely vestigial.

- Jim Katen, Oregon

[Jim Katen]

Originally posted by chrisprickett

Those holes mate with bumps inside the receptacle that keeps the plug from falling out and also improve the contact points. Some plugs just have spring action blades that serve the same purpose.

There are also some special outlets which allow you to lock the cord into the socket, by putting rods through the holes. This way, for example vending machines cannot be easiliy unplugged. Electrical devices can also be "factory-sealed" by the manufacturer using a plastic tie or a small padlock through one or both of the plug prong holes. A manufacturer might apply a plastic band through the hole and attach it to a tag that says: "You must do X or Y before plugging in this device". The user cannot plug in the device without removing the tag, so the user is sure to see the tag.

I'll be danged if I know what the holes are called.

I think Cecil does a fine job of explaining this one at Cecil's Storehouse of Human Knowledge.

http://www.straightdope.com/classics/a2_389.html

- Jim Katen, Oregon

[chrisprickett]

Here's where I got my info:

http://users.pandora.be/worldstandards/ ... .htm#plugs

Click on "plugs & sockets"