If you exist in the U.S. , you ’re almost in spades familiar with the holes in the prong of electrical wad . Many , if not most , American plugs have them . So what precisely are they for ?
The answer see back to the early 20th one C , when Harvey Hubbell Jr. patented a routine of electrical plugs ( starting with the first - ever detachableelectric plugin 1904 ) . Some of Hubbell ’s designs featured prong withindentsthat aligned with piffling bumps inside electrical sockets . When you inserted a plug into a socket , the indent - and - bump organization aid guarantee the prong in place . The indentation finally gave way to hollow , which , according to HowStuffWorks , functioned the same way .
But that ’s only part of the story . AsvariousYouTubershavedemonstrated , modernistic vent typically no longer have the bumps — they use detrition and force per unit area to keep plugs from falling out of the wall . These sidereal day , the yap serve other purposes . Some manufacturer , like those in the video below , insert a rod cell through all the hole in a seam of prong to lock them in place while they incase them in plastic .
prophylactic messages can also be threaded through the holes , effectively guarantee that consumers see the warning before using the attached gimmick . Manufacturers can even tighten a diminutive whorl or zip - tie through one or both holes as a entail offactory - waterproofing . Another popular hypothesis is that the holes deliver alloy , which help cut costs over sentence .
According to officialregulationslaid out by the American National Standards Institute ( ANSI ) and the National Electrical Manufacturers Association ( NEMA ) , the fix are “ optional ” and “ intended for manufacture purposes only . ” But if you desire to put a tiny padlock through a plug hole to keep your kids from powering up sure gadget , NEMA probably wo n’t beware .
