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AC Mains Connectors: Who Knew?

Dan Romanchik
12/29/2014 00:05 AM EST

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KeepItSimpleStupid
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Re: Mains connectors
KeepItSimpleStupid   1/15/2015 3:44:41 PM
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I wish that the NEMA 3-15P always had a wide plug for neutral.  Some wall-wart case manufactureres like Polycase, don't even offer polorized wall wart type boxes.

I got a Chinese LiiIon wall wart type box and the prongs rotate, but they barely have enough thickness to engage.

Stadards are not working.

zeeglen
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Re: Deficient Standards
zeeglen   1/1/2015 1:17:52 PM
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@ cookiejar ...and the two plies have to be separated in order to again mate reliably with another socket.

Interesting observation, I remember years ago those 2-ply male prongs (North America) and spreading them open with a small flat screwdriver to get them to work again.  But now that you mention it, seems that all newer male contacts are solid and can no longer be reworked.  Maybe this is to encourage replacement of the female wall outlet when worn.

David Ashton
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Re: Mains connectors
David Ashton   12/31/2014 11:37:06 PM
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@DocD.....personally, I have faith in Africans to find ways round the rules themselves.  In Zimbabwe it is called "Bush Mechanics".  Wherever poor people cannot afford electricity, they will find ways round it, and yes it is dangerous.

Even in Australia I have seen two table knives bound together with wire to replace a mains fuse that was pulled - and removed - for non payment.  How they got the knives into the fuse holder I don't know - as it was the main fuse it could not be switched off.  

 

cookiejar
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Deficient Standards
cookiejar   12/31/2014 10:29:20 PM
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I've noticed that some115VAC male plugs have solid prongs, while others have two ply springy ones.  I've also noticed that some A.C. receptacles have stiff solid contacts, while others have springy ones.


As long as one end is springy, the other can be solid or springy for reliable connections.  If both ends have solid contacts, I've often had trouble making contact.  If stuck, I've resorted to putting a twist in the solid male contact to make the connection function.  Sometimes the springy male contacts get flattened together by stiff female contacts and the two plies have to be separated in order to again mate reliably with another socket.


So in my experience, the so called standards have failed miseably to ensure reliable connections, which I would assume would be one of the purposes of standards.  It makes me wonder how many fires and casualties have been caused by such slack standards.

docdivakar
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Re: Mains connectors
docdivakar   12/30/2014 4:17:38 PM
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@David Ashton Re: "...But I thought that was the Zimbabwean way..." true, but that is after Indian merchants landed in many African countries and taught them a thing or two! Seriously, messing with AC outlets is quite dangerous and there have been many deaths over the years due to electrocution in India. You will be flabbergasted to know how many people toss hooked wires across AC lines to tap power illegally in India!

MP Divakar

Wnderer
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Use properly rated plugs
Wnderer   12/30/2014 12:06:44 PM
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Some years back I dealt with an issue where some of the cheaper 320's were not making good contact. This led to periodic arcing and heating which slowly carbonized the plastic until it turned into a resistor and caught fire. I believe the rating agencies have dealt with the problem so properly rated cables will not have this problem anymore. Don't fool around with AC power connectors.

David Ashton
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Re: Mains connectors
David Ashton   12/30/2014 2:23:57 AM
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@Prabakhar But I thought that was the Zimbabwean way.....  :-)

prabhakar_deosthali
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Re: Mains connectors
prabhakar_deosthali   12/30/2014 2:09:18 AM
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Want to know the Indian way of making a socket universal?

 

Just do not use any plug.  Directly insert wires into the socket and seal them with a tape. 

No hassles of bending or any sort of finding what comaptible plug to put.

 

Off course that was the old way ! 

Now things have improved and we get universal adapters while travelling overseas !

David Ashton
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Re: Mains connectors
David Ashton   12/29/2014 9:35:42 PM
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@Bert... " in a pinch, you can actually bend the flat prongs of Aussie plugs to fit in US sockets. (I never tried, and wouldn't recomment it!)"

I have tried that the other way round (ie bending US plugs to fit Aussie sockets) and no, I wouldn't recommend it either :-)

Have not been to Nigeria but have been to some other countries in the region (Ghana, Ivory Coast, Senegal) and I'm not surprised....I saw some VERY dodgy installations in those places, and in my old home of Zimbabwe.    In contrast, Australia is so highly regulated that everything has to be done properly.  Which leads to overkill, sometimes....

 Oh and BTW the photos are just off the net, though carefully selected for EET columns so they don't go off the edge... :-)

Bert22306
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Re: Mains connectors
Bert22306   12/29/2014 8:12:46 PM
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Nice photos, David. When we lived in Nigeria, we had a possible four different types of connectors in the house, for normal loads. And then others for the heavy kitchen loads. The oldest had only two cylindrical contacts, Euro style. The newest were those huge British types, with rectangular prongs.

In some European countries, the springy part of the connector is in the wall socket, and the plug's prongs are solid (e.g. Germany, similar in that respect to US). In other countries, Italy and France for instance, the prongs of the plugs have a slit in them. They are meant to squeeze into the socket holes.

The US design, and the Australian ones which are quite similar, are nice because they offer lots of contact area for the size. So they can be rated for 15 amps, and even 20 amps, while still being very small. Someone told me that in a pinch, you can actually bend the flat prongs of Aussie plugs to fit in US sockets. (I never tried, and wouldn't recomment it!)

One comment I had was that the two-pronged US plugs, nowadays, are almost always polarized, unless they are part of a "wall wart" transformer. The article does say that the NEMA 1-15-P prongs are of different widths often, but not why. The wider prong is meant to be used for the neutral contact always, in two-pronged plugs. So for example, in a properly wired table lamp, the threads of the Edison socket would always be wired to the neutral, so you shouldn't get a shock if you hot swap a light bulb and accidentally touch the threads. It's practically impossible to buy extension cords in the US, that don't have polarized plugs, and by the same token, wall sockets that aren't correspondingly polarized.

These are some of things I obsessed about as I was growing up.

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