wall plug wiring

While looking at this wall plug, I noticed it has a designated side for white wire, and a designated side for black wire. In the past I never saw that on a plug and just put it on whichever side was handy.

Is there a valid reason for putting a specific color wire on a specific side? I personally wouldn't think so, but maybe an electrician would know a reason, or someone more knowledgeable.

Reply to
dangerous dan
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There's been a definite neutral and line side since the introduction of polarized plugs and three wire circuits. That goes back at least to the '60s if not earlier; I don't recall just when precisely.

Reply to
dpb

Turn off the circuit breaker for that outlet

Neutral (White) goes to silver screw

Hot (Black) goes to gold screw

Step by step available all over the internet; just Google it or go to

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Reply to
Unquestionably Confused

Plugs should be polarized for proper grounding of appliances plugged into the receptacle. You will also notice that plugs have one prong larger to mate with the wider slot of the receptacle to everything is properly polarized. Small prong is hot, wide is the neutral. Yes, your lamp will light either way but you toaster may shock you if not properly grounded.

If you look at lamp cords you will notice that one side looks a bit different than the other side, usually ribbed. That is so if you splice it or put a new end you can get it right. Smooth is the hot side, ribbed is neutral.

Reply to
Ed Pawlowski

  • the hot wire goes to the smaller slot in the socket. Less likely to have foreign objects stuck in the smaller slot. (Think kids with metal objects.)
  • With polarized plugs, the hot goes up to the switch. So when the device is turned off, the wires in the device are not powered.

Safety reasons, for sure.

Reply to
Stormin Mormon

Also worth knowing WHY, precisely. There is a good reason which does make sense.

Reply to
Stormin Mormon

Congrats, no N word, no stupid puns, nothing political...I bet you feel better too?

Reply to
bob_villain

I don't know of any appliance that relies on the neutral for actual grounding. Two wire devices are not grounded and AFAIK, they don't have the case connected to the neutral. Polarization is important because the appliance is designed to expect one wire to be the hot, the other the neutral. For example, with a simple floor lamp, the tab at the bottom goes to the hot side, the side of the socket to the neutral. If the light is left on while changing a bulb, it's easier to accidentally touch the side, not so easy to touch the tab at the bottom. With the side at neutral potential which is close to ground potential, if you touched the side of the socket while standing in water, you shouldn't get a shock, any voltage potential there should be minimal. With other appliances, similar applies. The switch to cut off power to the appliance is going to be on the side that is supposed to be hot for example. The appliance would still work plugged in the other way, but if you start to take it apart while it's plugged in, have the switch off, parts that you think would not be energized, will be.

Reply to
trader_4

Really ! ? Are you saying that the metal body of my toaster is "grounded" to the neutral wire of the power cord ? for safety. Imagine that someone forces the 2-prong polarized plug into the wall - - backwards ! John T.

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Reply to
hubops

No, that would not be the case. The "hot" wire would simply go to the switch. Any device with a grounded case would require a three prong plug with a ground wire.

I don't know what year polarized plugs and outlets became the standard but I do know the outlets in the house my parents had built in 1957 had them. (No ground prong provision though)

Reply to
philo

Do you mean the wall outlet, the receptacle? I think so. (Or the plug on the end of the cord?)

That's why they call you dangerous dan. They haven't always been labeled white and black but the screws were silver and brass colored and people who connected them were supposed to know which went to which. This goes back to the 50's and I think earlier. The practical light bulb only goes back to 1870.

Reply to
Micky

Trader4 explained it better than I did. Your toaster may be grounded with a third wire to ground or may be double insulated. My old toaster had an outside plastic housing but new toaster has a 3 wire plug and metal housing.

Reply to
Ed Pawlowski

Trader summed it up nicely. If you have the polarity swapped on your toaster, the switch is opening the neutral and when you stick the fork in there to get the bagel out, it will light you up.

Reply to
gfretwell

Well, that's why they call it a toaster.

Reply to
Micky

As was stated, outlets have had designated sides for decades.

Even though it's "alternating current", here's a good explanation I found online why it's best to properly put the wires where they belong.

Let's talk about cord plugs and their connection to light fixtures. As you may know, most light fixtures have only two wires, a "hot" wire and a neutral wire. Believe it or not, there is a right and wrong way to connect these two wires, even though the light will light either way, and here's why. If you ever followed the two wires up to the light socket, you'd see that one connects to the inner bottom contact portion of the light socket, where the bottom of the light bulb makes contact. That is intended for the "hot" connection wire. The other wire is connected to the screw portion of the bulb socket where the bulb screws down into the socket, we'll call this the side of the socket and bulb for visual purposes. Now let's just think about the dangers of hooking the "hot wire to the side connection of the socket. See anything wrong here yet? Now, visualize yourself unscrewing the bulb by grasping around the lower portion of the bulb where the metal screw part of the bulb is exposed. You unscrew the bulb a bit and then take a second grip of the bulb and "BAM"! You got shocked! It's all because the screw part of the bulb is now the "hot" connection and you became the path to ground.

Reply to
Meanie
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Also, there's a thin piece of paper between the screw contact and the outer shell of the socket. That paper could be torn and/or bent making the exposed part live.

Reply to
Mark Lloyd

In about 1945 our milk was delivered to the house. The milk bottle had a paper cover held in place by a wire. I was about five hears old, and knew there was electricity in the outlet, and wire conducted electricity. One morning I took the morning's milk wire and poked its two ends into an outlet. The wire exploded and burned my fingers. I think I had a "Near-Darwin" experience!

My parents built the house in 1942, and original outlets had silver and copper sides. There was no ground terminal, but the silver side had a wider slot. I think the silver-copper convention may go back to the introduction of that style AC connector.

Fred

Reply to
Fred McKenzie

Or you could put 100 watt bulbs in a ceiling fixture rated for 60w. with a glass globe around each bulb. After 20 years the plastic around the metal socket crumbles and all you have is the metal socket!!

Reply to
Micky

Ibelieve some of this goes back to the AM radio days, when tranformless radios first started appearing on store shelves.

one side was hot, the other side connected to the radios case, which worked fine with the transformer isolating the outside case.

no transformer no isolation ZAP:(

Reply to
bob haller

Always has been the differentiation, and for VERY good reason!!! One side is referenced to ground - the other side is 120 volts above ground potential. With polarized plugs or grounded outlets it is very important which is which.

Reply to
clare

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