Holes in appliance plug prongs?

OK - I found it myself, since nobody swooped in!

I got this from:

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

Type A and B plugs have two flat prongs with a hole near the tip. These holes aren't there without a reason. [I knew it!(M)] If you were to take apart a type A or B socket and look at the contact wipers that the prongs slide into, you would find that in some cases they have have bumps on them. These bumps fit into the holes so that the outlet can grip the plug's prongs more firmly. This prevents the plug from slipping out of the socket due to the weight of the plug and cord. It also improves the contact between the plug and the outlet. Some sockets, however, don't have those bumps but just two spring-action blades that grip the sides of the plug pin, in which case the holes aren't necessary.

And there you have it

Nicely asked, and answered!

What a great post. You asked a clear question with enough information the someone could provide a reasonably accurate answer but more importantly you showed that not only were you capable of search for the answer but DID! To add to the quality of the thread you came back and shared the information you found. I am sincere when I say that a this is a great post.

Thanks to both you and Steve. It just seemed logical!

Mike

ashman back; I just did a contract job that got thinging...Hummmmm! Could the holes be there perhaps as locator hole for a fixture during later injection molding of the surrounding plastic components? Or to define the correct pin is on the correct side of the plug. ( I'll explain for those that may not have 120VAC as household power ). In North Americal the plug is polorized. A hot lead 110-120VAC and a Neutral lead, ( which is actually tied to ground but not the path of least resistance. Where-as in the UK a two prong plug carries two hot leads of differing phase angles resulting in a 220 across ). So, those holes could, and I don't really know be locator pins. ash

In SA we don't use that plugs. The first thing you do is to cut the cable and fit a 3 prong 35Amp plug. (Why 35amp i dont know - a child can get his finger in the hole with ease.)

People however found a nice use for the holes. The two wires of a piece of flex is stripped, pushed trough the holes and twisted tight. The other end of the flex can then be inserted in the 35Amp plug. Instant connection!

Just thought of something: one could attach a small padlock so as to prevent the plug being inserted in a socket! Now, what about that for 'parental controls'?

Thats wut I alwayz thot they wr for.

I think you should stick to responce 1-3. I'm not sure were SA is as I didn't check the profile but the kids there must have 14 AWG fingers or Big mother-**** plugs. The rest of them just seem to extend away from reality. Besides wouldn't you just love to think for a moment that it was some wacked out electrical engineer that put it in the spec just to confuse the heck out of us! It wasn't me, yet! & I'm not the Ashman. Even thou I goeth now.

SA = South Africa

The line and neutral are 1/4" and the earth is 5/16"

A safety gadget is fitted to newer models but people insert a pencil into the earth to keep it open. I suppose any system can be abused.

These days a typical outlet plug must at least be fitted with some adaptors to facilitate all the different standards.

You will say that it is not your problem and it is true but at least have pity on us.

In the UK we don't have holes in the plug prongs...

But we do have lockable 'plugs' which fit in the sockets to stop there use or abuse etc...

John.