Currently, I some of my light fixtures use nonpolarized plugs. I frequently designate a “live” side and a “neutral” side to those plugs since without those designations, I might accidentally reverse polarity. Does anybody else in North America besides me use nonpolarized plugs for lighting?

  Using non polorize plugs can be pretty dangerous  as 50 percent of times u plug them in reverse.   Well older table lamps and Christmas lights were like that.  But I rather use polerize plugs and cord.   As I dont want the Hazard to my self
 When I am messing with 120 volt.   Esp when u trouble shooting u want  be able to disconnect the hot lead first
Then I am safe from that point.  Keep in mind lots old american
 Preheat industral fixture came with no grounding either. 
  Id advise u that u keep up with modern  electrical codes for your safety and for others non lighting people.   It very easy
 To identifi lamp cords Neutral by a ridged side of lamp cord
 While other side is rounded.  Now grounding cords is get
 Least attention as 3rd prong tend get broken off.
 

If the polarized vs non polarized matters for your safety, then you are doing something wrong in the luminaire itself (or other appliance). (I am not about the "live shell on a medium lamp socket" issue now, so assume we are about Fluorescents, or in case of a lamp with screw base, you dont fiddle with the lamp when it is plugged in)

Let me explain why :

The only reason your safety would depend on the plug polarity, is if you might somewhere touch the Neutral conductor in the appliance - And you want to make sure that it really is Neutral and not Phase

And then, this is your real safety problem. The Neutral conductor is not touch safe and cannot be assumed to be. It can become live under different conditions, including :

 - Bad connection in the Neutral (The 120V will arrive from the Phase through the appliance)

 - Powering from a supply source with undefined Neutral, such as some generators, inverters, UPSes, IT system, etc... (The Neutral in such systems is undefined, the voltage between "Neutral" and Earth can be anything between 0..120V. In higher end systems like what's in some RV's, there are isolation monitoring signals present in there, which means you'll trip fault alarms if you touch the "Neutral")

 - Extreme overloads on the circuit, or just very long circuit (A voltage drop will appear on the Neutral wire)

 - Wall socket with reversed Phase and Neutral

 - Miswiring at any point in the circuit or lamp gear



The only proper solution is to treat the Neutral same as you would treat the Phase, and isolate it to the same level. Once you do that, the plug polarity does not matter for your safety anyway

For appliances with a switch, where you would prefer the switch to be on the Phase : The same applies. If all conductors, Phase and Neutral inside the appliance are isolated to the same level, then to you from outside it does not matter, that the appliance is "live inside" when the switch is off because it happened to be on the Neutral. The apppliance is off and is safe to touch from outside

Ash, your argument only works if ALL manufacturers adopt the same standards and put double-pole switches in all appliances.

And I will come back to screw-thread lampholders again; not all lampholders are built so that the shell cannot be touched when the lamp is inserted. Also, not all lampholders are designed so that the shell of the lamp is isolated until the lamp is fully screwed in. Some are, but many are not. So it is possible for the thread to be live when a switch in the phase wire is off if a non-polarised plug is inserted the wrong way. And the vast majority of people are stupid; they will insert lamps without unplugging the fixture, they will still fit single pole switches, they will do their utmost to qualify for the Darwin awards.

No amount of arguing is going to change that. Polarised plugs make life easier and safer, simple. Why are you so against them..?

Generally no, I dislike using unpolarized plugs as I prefer my lights to be connected the way it's intended too. I know in most cases a unpolarized plug will work either way but then I have to ensure that I either plug the plug in the right way or use things like double pole switches. Lampholders with a touch safe shell don't exist here so I can't use those either.

I also like to ground all of my metal cased lights for safety so that basically means I have to use a polarized plug. The only time I use a two prong plug is when I'm connecting something with a plastic body like a plastic traffic light.

PLEASE ! Nobody shoot me for this . I use a mix of newer and older X-mas lights , some with polarized plugs , and some without . The polarized ones cause me MAJOR hassles when hanging my lights . I will freely admit to filing down the wide blade so I can go about my decorating without having to fool with adapters and such. I am also NOT a fan of the fused plugs. I have a number of light sets that have had a standard plug installed in place of the fused one. 

Here the plugs are not polarized, but the ground is always connected so in most cases there's no problem, the problem comes when your house is not grounded or you use dodgy Chinese stuff with no ground connection. There is a problem with lamps though, when you connect it backwards the outer part of the screw expose the live. I don't really like polarized plugs, because as same as USB connectors they won't fit at the first try and that's quite irritating.

It's ok Tim, I won't shoot you, I don't much like guns    You might get a  though, if you really want one 

Your electrical systems are different to ours though, so I do understand why you don't like some plugs, the reason we have fused plugs is historical, due to the ring system we have. It's falling out of favour now, and few electricians still install them, but they're still very common and it'll take a long time for them to disappear completely, if they ever do.

But I do prefer polarised plugs, for the reasons I've stated. Manufacturers, especially those in certain far eastern countries, produce things to a price, not a quality or safety standard. I would prefer not to take the chance that a lampholder, for example, could be connected the wrong way round.

What I really don't understand is why polarized plugs are installed on series wired X-mas light sets. Regardless of the way they're plugged in , every thing in the string is still live! I've been shocked more times by those things than any parallel string !

Here the plugs are not polarized, but the ground is always connected so in most cases there's no problem, the problem comes when your house is not grounded or you use dodgy Chinese stuff with no ground connection. There is a problem with lamps though, when you connect it backwards the outer part of the screw expose the live. I don't really like polarized plugs, because as same as USB connectors they won't fit at the first try and that's quite irritating.

Usually USB plugs have the little symbol either pointing towards you or facing up, so a quick glance is all you need to get it right.

What I really don't understand is why polarized plugs are installed on series wired X-mas light sets. Regardless of the way they're plugged in , every thing in the string is still live! I've been shocked more times by those things than any parallel string !

Well here, we don't have 2-pin plugs, except perhaps for shavers and toothbrushes. All appliances, whether they have an earth/ground connection or not, are fitted with a 3-pin 13A plug, with the appropriately rated fuse. The earth pin in these cases is often either unconnected or made of plastic. Thus it is impossible to get it wrong when plugging in, as the earth pin is larger and always at the top (or bottom if you're upside down like an Australian  )

[ Waits for backlash from the southern hemisphere  ]

What I really don't understand is why polarized plugs are installed on series wired X-mas light sets. Regardless of the way they're plugged in , every thing in the string is still live! I've been shocked more times by those things than any parallel string !

From what I understand, only the parallel strings have polarized plugs with integral fuses while the series strings have nonpolarized plugs.

Double pole switches have nothing to do with polarized plugs. The problem you see and try to avoid is, what happens when the switch is OFF, it is on the Neutral, so the appliance is not "working" but all its internals are live

The answer is that this is not a problem - The internals of the appliance are enclosed inside, and are isolated from anything the user may touch on the outside. So they can be left live



The E26 socket shell contact is one thing that cares about polarity for safety, but :

1. This design has its safety issues even with a polarized plug in place - For example, when the N wire gets disconnected, the screw shell becomes live (thorugh the lamp filament). Since it is in a lamp that has a plug, all safety issues are solved by unplugging it when screwing with the lamp - but then it is safe no matter what plug it uses.... So taking things into proportions, only so much of the overall safety of the luminaire actually depends on the plug polarity of all things

2. What about Fluorescent desk lamps ?

I am pointing out that the reliance on plug polarity for safety (and as result, the emphasis of importance of plug polarity for safety), is just a band aid measure to cover up some serious design problems : Grounding things to Neutral (very dangerous, yet as far as i understand, was the case with some old US washers/dryers), User accessible parts in the appliance connected to Neutral (E26, ....), etc

An appliance which comes with non polarized plug, guarantees that its maker have made no assumptions that any current carrying part of it is ever safe to touch, and took care to isolate all of them adequately

A polarized plug in itself does not make the appliance more dangerous, instead, it's the requirement for a polarized plug (for safety reasons), that rises doubt in the correctness of the design of the specific appliance



Things made down to a price - That implies quite a lot of potential for safety problems all over the place. They are very unlikely to be resolved by observing correct plug polarity, simply because 99% of safety problems of cheap appliances have nothing to do with polarity whatsoever, and 1% is not what somehow makes a bad appliance safe

Take as example your lamp with the E26 with exposed threads : Would you poke fingers in there, even when knowing that the plug is polarized and inserted correctly ?



Grounding is an important safety feature when metal case is involved

In most countries the presence of ground in a plug makes it polarized, however, those features (ground and polarized-ness) are not essentially related. Some examples to the contrary include :

Schuko (Germany and many other countries) and 10A/16A Italian plugs (Thats what you have Binarix, right ?) : Grounded yet not polarized

French standard (France and many other countries) : The plug itself can be inserted only one way, but there is no standard whatsoever on how it is wired (there is no designated pin for Phase or Neutral, you just wire it whatever way you want). The wall sockets are also wired whatever way one wants to



In series Christmas lights, the polarity makes no difference whatsoever, so its quite logical that the plugs will be non polarized :

The lamp nearest the Phase is live on both ends (it is 120V on one end and 112V on the other for 8V lamps, not really a difference....), so have to be adequately isolated on both ends. (So if it would be a screw base lamp, both its shell and center contact would be live in normal operation)

The other lamps are all identical, so they too have to be adequately isolated on both ends

Then the entire string is adequately isolated on both ends anyway....

And that's before we even count in lamp EOL scenarios, when the string will be live at full 120V from Phase up to the bad lamp

@ Ash here most common mintjre lamps in xmas set would use 2.5-3.5 volt in a sting of 50 lamps it  ive been zapped many
Times over  by those sets. 


@ worldwidehidlamps u must not bought modern strings of
 Xmas mini light lately as it hace polerize plugs. 

Funky Bulb is correct ! The new mini light strings DO have polarized fuse plugs ! As far as I've seen , anything new that doesn't have a grounded plug has a polarized plug .