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Inside of 120vac 'Safety' Plug?

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MrAl

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Hi,

Anyone see these so called 'safety' plugs?

The ones i have seen in the past have a small door that opens and there is a small fuse inside. The fuse can be replaced. Good idea.

The one i just encountered recently however has no door, but still says not to replace it because it is a 'safety' plug.

I am guessing that it just has a fuse inside, but thought i would ask around. I cant open it up because the device still works so i dont want to ruin it. I've seen some pictures on the web that show a fuse but it doesnt look like the exact same type.
This type looks like an ordinary plug only is a little bit longer from where the wire enters the plug body to where the prongs start. It only has two prongs and plugs into an ordinary two or three prong 120vac 60Hz outlet.
 

crutschow

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It may be a GFI (GFCI) plug to protect against electrocution by the user of the device.
They open circuit if the hot lead current is more than the neutral lead current by a few mA.
They're often found on hair dryers.
Does it have a reset button?
 

MrAl

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Hi,

Eric:
Oh yes that would be nice. I guess no way to test for this though.

Carl:
Well only two prongs as i stated in my first post.
 

MrAl

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Hello there,

Thanks for the link as that is informative too, but again, the plug ONLY has TWO prongs, NOT three. A ground fault interrupter must have three prongs not two, because it needs that third prong to sense a ground current fault. As far as i know, that's the way they all work, including the ones installed in the outlet receptacle boxes normally used in houses and buildings. They would then have three holes one for each prong, and the ground prong is shaped sort of like a "U" (a letter of the English alphabet). The particular plug i was talking about only has the two flat prongs so this third U shaped prong is absent.

I can provide a picture, but it's just a simple two prong plug a little longer than usual that's all. There's no way to open it up as it is molded as one piece or two pieces that are later sealed together using some permanent joining process.
 

KeepItSimpleStupid

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the plug ONLY has TWO prongs, NOT three. A ground fault interrupter must have three prongs not two, because it needs that third prong to sense a ground current fault.
MrAl, a GFCI only requires H and N. In fact they are allowed in 2 wire circuits if properly labeled "No Protective Ground"

Here http://docs-europe.electrocomponents.com/webdocs/1323/0900766b8132342c.pdf?#Page=7 on page #6, PDF page 7, is a GFCI circuit. Do you see a ground in there? I don't.

The subtraction is done with two coils wound together so they subtract. Another winding amplifies this.

Another coil senses a grounded neutral and it does this without a ground. In general the GFCI detects the wrong polarity too.

And if you don't believe me: https://www.nachi.org/forum/f19/gfcis-2-wire-circuits-38554/

There's a two prong one on my hair dryer with a test and reset button.
 
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crutschow

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Deleted redundant post.
 

ClydeCrashKop

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"If a ground fault were to happen on the hot side of the power line, there would of course be all kinds of spectacular spitzensparken, fussinmussin and smokineven going on. There'd certainly be no question about detecting that."

Ha Ha
 

MrAl

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MrAl, a GFCI only requires H and N. In fact they are allowed in 2 wire circuits if properly labeled "No Protective Ground"

Here http://docs-europe.electrocomponents.com/webdocs/1323/0900766b8132342c.pdf?#Page=7 on page #6, PDF page 7, is a GFCI circuit. Do you see a ground in there? I don't.

The subtraction is done with two coils wound together so they subtract. Another winding amplifies this.

Another coil senses a grounded neutral and it does this without a ground. In general the GFCI detects the wrong polarity too.

And if you don't believe me: https://www.nachi.org/forum/f19/gfcis-2-wire-circuits-38554/

There's a two prong one on my hair dryer with a test and reset button.
Hi again,


Yes i believe that is right, not sure what i was thinking there earlier. The device works on current not on voltage so it basically detects a leakage current by comparing current in and current out and they must be equal or someone is getting current through their body to earth ground :)
So it could be a GFCI.

Thanks for the additional links also.
 
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