2-prong electrical devices

Can 2-prong electrical devices always be plugged into an outlet either way? If so, why is this?

Reply to
mike7411
Loading thread data ...

They can if the plug will fit. Some have one side of the plug bigger than the other . This means they can usually be plugged in only one way.

For AC it does not mater which side is used as the current is reversing 60 times a second. It does make a small safety differance sometimes incase of electrical problems.

Reply to
Ralph Mowery

Hey! I must have slow electricity, because mine only reverses 50 times a second. What's the skinny on that, Ralph? Also, do airplanes go faster because their electricity reverses 400 times a second?

Reply to
mike.j.harvey

People who use cheap audio amps made in the '60s know that flipping over the AC plug can reduce hum. (Fender amps had a switch that let you chose.) . .

Hot, neutral, ground.

formatting link

Reply to
JeffM

Slow electricity for slow countries. Yes the planes do fly faster because of 400 reverses per second.

Reply to
Ralph Mowery

"Ralph Mowery" wrote in news:ztVmg.71$ snipped-for-privacy@newsread1.news.pas.earthlink.net:

Agreed.

My mileage has varied on this. My Dad's tube amp has to be plugged in properly to prevent electric shock to the user. Yes, it still works fine with the plug reversed, but good luck turning it off!

It makes a BIG safety difference.

Puckdropper

--
Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm
Reply to
Puckdropper

On 25 Jun 2006 05:28:21 GMT, in message , Puckdropper scribed:

The hazard here is caused by the user becoming a path from the switch to ground. It sounds like the case on the amp is tied to one of the AC legs, so it is crucial that that leg be the neutral (unless the user could be certain that he or she has sufficient insulation from ground). The *best* way to handle this is to isolate the case and run a three-prong plug with the case grounded. The design of the amp might rule that out as an option.

Polarized AC plugs are making use of the NEC code that requires the neutral side to be tied to earth ground in the main household circuit breaker panel. Non-polarized plugs can be used for things like rectifiers, where the AC in will not normally be accessible by the user. Things like floor and table lamps have, in the past, used non-polarized plugs, but that leaves the way open for a shock hazard when changing a bulb on a live circuit. The three-prong plug is used when the device has a case that should be grounded, and carry no normal current.

Reply to
Alan B

I once did a sort of demo of this effect; I was a teenager, with some other teenagers in a big garage with a moist concrete floor, and we were all barefoot, and the guy was getting hum through his guitar amp. I said, "Oh, just turn the plug around." Which I did, and while standing on the moist concrete barefoot I reached out with a flourish and laid my hand across the guitar strings. BZZZZZZAW!!!! It seems the original hum wasn't from a backwards plug.

Cheers! Rich

Reply to
Rich Grise

When I was in the Air Force, they used to send guys out to check the box of dirt in the airplane's tail that they use for Earth ground. ;-)

Cheers! RIch

Reply to
Rich Grise

So, you are using 25 Hz electricity?

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
 Click to see the full signature
Reply to
Michael A. Terrell

OK - you got me fair and square on that one. Loose language. Although I'm in (good? not sure!) plentiful company, The Arizona Collaborative for Excellence in Preparation of Teachers says in their electrical safety course for teachers in that state:-

formatting link

[quote] The rate at which the current reverses direction is set by the power company, and in the U.S. is (unfortunately!) 60 times each second (60 cycles/second or 60 Her). Hence we refer to the electric power delivered to our homes as 120 volt, 60 Hz electric power. [/quote]

Wisconsin too...

formatting link

[quote] Electrical generators in power plants throughout the United States produce alternating current that reverses direction 60 times per second. [/quote]

But not in Virginia...

formatting link

[quote] However, the alternating current in the United States reverses 120 times a second in order to complete 60 full cycles each second. ... [/quote]

Is this a North-South thing?

Reply to
mike.j.harvey

Only of the zero volt base line. ;-) As for me, I was born in Kentucky, but grew up in Ohio. I have lived in Alabama, Alaska, and Florida, as well.

I have read and written too many technical papers to let errors like that continue unchallenged. My teachers always got upset when I raised my hand to point out an error in a textbook, or a lesson. Thanks for the links to the bad data. I love to point out bad websites to the authors. Some are very stubborn and refuse to correct their pages, while others quickly make the changes and thank you for politely pointing out their mistakes.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
 Click to see the full signature
Reply to
Michael A. Terrell

Maybe the seconds are longer/shorter depending on location. Or electricity is faster in the south than it is in the north?

Ed

Reply to
ehsjr

reverses 50 times a second, goes forwards 50 times a second, changes direction 100 times a second.

--
Bye.
   Jasen
 Click to see the full signature
Reply to
jasen

That is NOT what the message said, and you know it.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
 Click to see the full signature
Reply to
Michael A. Terrell

How does Jasen define "forwards"?

Surely, a single phase sinusoidal AC waveform has two peaks, and therefore reverses twice, in each cycle?

Reply to
mike.j.harvey

Read a few more of his posts in different threads and you'll find that he has an opinion on everything, but rarely gets anything right.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
 Click to see the full signature
Reply to
Michael A. Terrell

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.