non-polarized plug

ionized_gwAugust 10, 2012

Why are non-polarized, two-conductor, replacement plugs being sold? What kinds of devices/appliances are they used for?

Thank you for reporting this comment. Undo
Ron Natalie

Most AC devicez don't give a hoot about "polarity". They only know the potential between the two leg, and care not if one side is grounded or not.

Only things that have exposed metal (light fixtures, certain electronic equipment) that are not fully insulated from the current carrying conductors require the plug keying to keep the grounded side grounded.

    Bookmark   August 10, 2012 at 12:50PM
Thank you for reporting this comment. Undo
ionized_gw

Thanks

    Bookmark   August 13, 2012 at 12:44PM
Thank you for reporting this comment. Undo
lbpod

Thanks Ron, you splained it beautifully.
I'm just thankful that the Brick didn't
give us his ultimate wisdom, or we'ld
have been her till Christmas. Amen.

    Bookmark   August 13, 2012 at 1:47PM
Thank you for reporting this comment. Undo
ionized_gw

Please be nice,

    Bookmark   August 13, 2012 at 2:05PM
Thank you for reporting this comment. Undo
brickeyee

"Why are non-polarized, two-conductor, replacement plugs being sold? What kinds of devices/appliances are they used for?"

Replacing plugs on two conductor appliances without polarized plugs.

Or do you actually mean receptacles?

    Bookmark   August 13, 2012 at 4:10PM
Thank you for reporting this comment. Undo
bus_driver

Using a table lamp as an example, the screw shell is to be electrically connected to the grounded conductor, the Neutral. The ungrounded conductor, the Hot, is to be connected to the built-in switch which in turn sends power to the center bottom contact in the lamp socket. Properly wired and connected with a polarized plug, the lamp assembly would not pose a shock hazard to a child poking a finger into the empty socket if the switch is Off. With a non-polarized plug, it is a 50-50 chance that the screw shell will be energized whenever the lamp is plugged in, no matter whether the switch is On or Off. With a non-polarized plug, or a polarized plug incorrectly connected, a person changing the "bulb" could get shocked as soon as the bulb base touches the screw shell if a finger is also touching the bulb base. Or the aforementioned child could get shocked by direct or indirect contact with the screw shell. Polarized plugs must be installed correctly.
Polarized plugs have a great deal to do with safety for people.

    Bookmark   August 13, 2012 at 5:09PM
Thank you for reporting this comment. Undo
alan_s_thefirst

As a kid in Ontario, I'm sure we had two-pronged plugs with lamps with the metal screw shell. Polarised plugs/sockets hadn't come out yet, so I GUESS they had a ground pin - I don't remember getting shocked - except when I put my finger in a light socket!

    Bookmark   August 14, 2012 at 12:55AM
Thank you for reporting this comment. Undo
bus_driver

Evidently there is some confusion about the definition of screw shell. It is possible for the caring to research it on their own.
The screw shell of a lamp socket is the female threaded portion into which the threaded base of the lamp is inserted by turning.

Here is a link that might be useful: Here is help

    Bookmark   August 14, 2012 at 7:07AM
Thank you for reporting this comment. Undo
ionized_gw

The reason that I started this thread was because in a recent visit to my father I found that he wanted to replace the plug on his vacuum cleaner with a non-polarzed replacement. I noticed that the original plug was polarized and vetoed the plan.

I guess that I have not been paying much attention to the fact that there are lots of devices that do not have polarized plugs. I have been looking in the past few days and I see that there are many. A week ago, however, If you had asked me I would have said that there are very few if any. My misperception might stem from the fact that in the olden days nothing was polarized and more modern stuff is so I assumed that non-polarized plug equipment was being supplanted rather than a modern option. I can see why a non-polarized plug is desirable since you don't have to pay attention to how it goes into the outlet.

    Bookmark   August 14, 2012 at 9:35AM
Thank you for reporting this comment. Undo
brickeyee

Polarizing the plug and receptacle is a simple way to ensure portable lamps keep the shell on the grounded conductor without major wiring changes (like adding a grounding conductor).

Many other things are double insulated, and require neither a ground nor a polarized plug.

Since two prong lamps do not have a grounding conductor, the risk of touching a live shell is still not all that great.
You have to touch both a hot and a return connection at the same time to be shocked.

A long time ago the chassis of equipment was sometimes connected to the grounded conductor.
That meant if the plug was 'reversed' the chassis was electrically hot.
Old radios, and all sorts of small appliances did this.

    Bookmark   August 14, 2012 at 10:38AM
Thank you for reporting this comment. Undo
w0lley32

"Why are non-polarized, two-conductor, replacement plugs being sold?"

I once asked that question to the owner of my local hardware store because all the 2-prong plugs he had were non-polarized, and he told me that he once carried them, but had to ship them back to the supplier because they didn't sell and he had many nasty comments from clients about their being too complicated to use for nothing.

    Bookmark   August 14, 2012 at 4:42PM
Thank you for reporting this comment. Undo
bus_driver

"A long time ago the chassis of equipment was sometimes connected to the grounded conductor.
That meant if the plug was 'reversed' the chassis was electrically hot.
Old radios, and all sorts of small appliances did this."

Very true. When the "All American 5" tube-type radios were popular, if a knob was removed or lost, the protruding brass control shaft could easily be at line potential.

    Bookmark   August 14, 2012 at 5:14PM
Thank you for reporting this comment. Undo
brickeyee

"if a knob was removed or lost, the protruding brass control shaft could easily be at line potential. "

And now you know why they used plastic knobs.

    Bookmark   August 15, 2012 at 2:56PM
Thank you for reporting this comment. Undo
ionized_gw

"Very true. When the "All American 5" tube-type radios were popular, if a knob was removed or lost, the protruding brass control shaft could easily be at line potential."

Now that you mention it, I think I got a shock from a tube radio once.

    Bookmark   August 16, 2012 at 11:12PM
Thank you for reporting this comment. Undo
lbpod

Excuse me Brick, but most of those old radio knobs
were bakelite. And I suppose you'll come back with:
"Bakelite is a type of plastic". You win Brick,
you win.

    Bookmark   August 17, 2012 at 1:50PM
Thank you for reporting this comment. Undo
brickeyee

You appear to have a real problem.

Sorry to see it so plainly exhibited.

    Bookmark   August 17, 2012 at 4:15PM
Thank you for reporting this comment. Undo
bus_driver

I think the bakelite was mostly phased (pardon the pun) out before the era of the All American 5. Most of the knobs I saw were styrene, sometimes with a brass sleeve inside.

    Bookmark   August 17, 2012 at 6:26PM
Sign Up to comment
More Discussions
Humming Transformer
Last summer the POCO replaced the transformer on the...
mike_kaiser_gw
1 of 2 security light bulbs keep going out, do i need a new light?
I have a security light fixture in my carport that...
tlbean2004
Wireless light switch for switched outlet?
So we have no overhead lighting in any of our bedrooms,...
vikingshelmut
Wiring in a 1 1/2" thick wall cavity
I need to run 12/2 wire thru an existing thin wall....
baker1mich
Confused & need help please
I know just about zero when it comes to electricity....
bicyclegirl1
Sponsored Products
Dogwood Leaf Doormat
Home Decorators Collection
Green Novelty Lamps: 14.5 in. 20 oz. Classic Lava Lamp, Blue and Green 2124
$14.97 | Home Depot
Chocolate Home & Porch Indoor/Outdoor Rug
$21.99 | zulily
Patio Living Concepts Catalina Bisque Umbrella Table Outdoor Lamp with Canvas Li
Home Depot
C9 PW C85313RY Commercial LED Christmas Lights
EnvironmentalLights.com
Domain All-Weather Area Rug
Home Decorators Collection
Almond LED Step Light Non Dimmable
$56.00 | PLFixtures
Hand Held Fan Control
$54.00 | Bludot
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™