# Electrical plugs with holes in the prongs

**URL:** <https://boards.straightdope.com/t/electrical-plugs-with-holes-in-the-prongs/335288>\
**Category:** Cecil's Columns/Staff Reports\
**Created:** [December 12, 2005, 6:45pm UTC](https://boards.straightdope.com/t/electrical-plugs-with-holes-in-the-prongs/335288 "2005-12-12T18:45:52Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Robin\_Bather](https://avatars.discourse-cdn.com/v4/letter/r/c2a13f/32.png) [@Robin\_Bather](https://boards.straightdope.com/u/Robin_Bather)\
**Post date:** [December 12, 2005, 6:45pm UTC](https://boards.straightdope.com/t/electrical-plugs-with-holes-in-the-prongs/335288/1 "2005-12-12T18:45:52Z")

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I live in Mexico and although it is dangerous and forbidden by all electrical standards, it is very common to see workmen hook a bared wire through each of the holes in the prongs and then wrap electrical tape around the whole affair.  
You then have a very economical extension cord. :smack:  
I always thought that the holes were for this bad and non recommended practice.

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**Author:** ![Nekosoft](https://avatars.discourse-cdn.com/v4/letter/n/c2a13f/32.png) [@Nekosoft](https://boards.straightdope.com/u/Nekosoft)\
**Post date:** [December 12, 2005, 6:50pm UTC](https://boards.straightdope.com/t/electrical-plugs-with-holes-in-the-prongs/335288/2 "2005-12-12T18:50:03Z")

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Here’s a link to Cecil’s [column](http://www.straightdope.com/classics/a2_389.html), so that everyone’s on the same page.

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**Author:** ![j2browning](https://avatars.discourse-cdn.com/v4/letter/j/ccd318/32.png) [@j2browning](https://boards.straightdope.com/u/j2browning)\
**Post date:** [December 13, 2005, 7:57pm UTC](https://boards.straightdope.com/t/electrical-plugs-with-holes-in-the-prongs/335288/3 "2005-12-13T19:57:34Z")

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I’ve done that.

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**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\
**Post date:** [December 13, 2005, 8:04pm UTC](https://boards.straightdope.com/t/electrical-plugs-with-holes-in-the-prongs/335288/4 "2005-12-13T20:04:16Z")

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I was able to answer it in this thread.

> **[Holes in the prongs of plugs](https://boards.straightdope.com/sdmb/showthread.php?t=334577)**
>
> http://www.straightdope.com/classics/a2\_389.html For sure the UL guy is way off base. In order to use holes to improve cooling, the holes must be configured in a way that increases surface area. The formula for this is that the diameter of the hole...

Maybe Cecil could update the Article one day.  
I have know idea what the procedure on that would be.

> [@JRFRANCHI](#):
>
> All Brass scrap from everything we stamp is recycled and sold back to the Metal dealer. We get giant rolls of Brass Sheet metal cut anywhere from 1" to 8" wide.  
> The rolls are maybe 5’ across.
> 
> According to our resident long term stamping Engineer; the holes are used by the stamp press to align the stamping of the blades. These are large, very noisy automated machines.  
> So to answer the original question: The holes are part of the stamping operation itself and have no special electrical or mechanical design.
> 
> (I work in the office as I am a Programmer/Analyst and we share the same slab as the Stamping floor. When some of the stamp machines are going the whole building shakes)

Jim