Why are modern pus polarized?

[Beamin]

This always baffles me since the only time it seems to mater is in old tube sets where you have a hot chassis depending on how its plugged in. But ironically many old tube sets have standard plug. We don't need safety because people knew better back then to touch electronics while they were on and if they didn't they learned quickly or died.

Would it matter in a motor?

[ebastler]

"pus"? 

[SL4P]

My pus comes out any ol’ way it likes.
Always has.
I don’t have any control over it 

[BravoV]

"pus"? 

Maybe she is bored , as usual.

[PA0PBZ]

Plugs? They are not (in my country).

[CJay]

In my country, where we care a bit about safety, the 'old tube sets' are a major reason why we have polarised plugs, people used to electrocute themselves.

Didn't stop people wiring plugs wrong though so the first check for every new repair job on an item where there was a rewireable plug was to open the plug and make sure it was fitted properly, safely and had an appropriate fuse.

There were a rather shocking (intended) number that were dangerous, wires stripped back too far so conductors were exposed, fuses wired out or wrapped in aluminium foil, 15 amp fuses for a device that only needed a 3 or even a 1 amp fuse, wires splice by twisting together and 'insulated' with sellotape, loose screw terminals, no strain relief, all sorts of horrors.

[Rerouter]

A well designed product should assume both wires may be live, However by standardising on 1 wire being active and one being tied to ground in most countries wiring systems, they can reduce the costs and complexity of the protective devices, e.g. only needing a fuse or circuit breaker on 1 wire instead of both

There are still countries that break both wires in there circuit breakers, however for the majority, its to reduce the risk of death, while keeping things cheap to implement.

[apis]

In EU there is a desire to standardise the plugs so we can use the same cord everywhere. The plugs we have now are a compromise to make something that is easy to integrate in all countries. Switching to polarised would have required everyone in EU to replace all their plugs and outlets (would have been a huge cost).

Would be nice if the entire world used the same plugs, line voltage and frequency, but it is just too expensive to change.

[Rerouter]

Well for mains plugs, a large number of consumer devices now have settled around the IEC mains plug, there is still a large number of small devices using the Figure 8, 2 pin plug, making it mostly universal, Even laptop chargers settled on the round 3 lobe varient.

The one thing that is always a pain is power bricks, If there was a pain free way to make them all start using IEC or an interchange connector, It would make things much easier to move from 1 country to the next.

[TerraHertz]

By "pus", did you mean "mains plugs"?  I don't think you can blame autocorrect for that one.

Anyway, edit the title to fix it, and then I'll tell you the one very good reason why they are polarized.

[Zero999]

I do like polarised mains connectors. Although a correctly designed appliance should be safe to use, irrespective of the polarity of the mains, in practise, many appliances are safer connected one way, than the other.

[ebastler]

I do like polarised mains connectors. Although a correctly designed appliance should be safe to use, irrespective of the polarity of the mains, in practise, many appliances are safer connected one way, than the other.

So you assume your appliances to be incorrectly designed, but trust their mains plugs to be correctly installed? Hmm...

[Beamin]

"pus"? 

Maybe she is bored , as usual.

 haha I'm never bored when on the forum! I have a broken keyboard that I'm dealing with:

 Iwould fixit ut tislap top is my only computer soI have todeal with it.

Every sentence I typecomesoutlike this and I have to go back andfix all the mistakes and sometimes miss thesubject line because it doesn't make the red lines.

Frustrating to read isn't it?

[CopperCone]

[ebastler]

Frustrating to read isn't it?

Yes, on more than one level.

[BravoV]

"pus"? 

Maybe she is bored , as usual.

 haha I'm never bored when on the forum! I have a broken keyboard that I'm dealing with:

 Iwould fixit ut tislap top is my only computer soI have todeal with it.

Every sentence I typecomesoutlike this and I have to go back andfix all the mistakes and sometimes miss thesubject line because it doesn't make the red lines.

Frustrating to read isn't it?

You are clearly bored, as even on this 2nd post of yours, you're more interested to my bait, instead of answering/clarifying 1st, to those generous & sincere people that have been wondering about your puss ...

[SG-1]

When I was in high school my parents were renting the lower level of a duplex.  It had a big natural gas floor furnace with a grounded metal grate. We also had table lamp in arms reach, the plug was not polarized.  It was inserted such that the hot conductor was energizing the screw shell.  If you stood on that grate with bare feet & touched the lamp to turn it on or off, it really hurt.

Did not know at the time to just flip the plug over !   

[JohnnyMalaria]

In my country, where we care a bit about safety, the 'old tube sets' are a major reason why we have polarised plugs, people used to electrocute themselves.

Didn't stop people wiring plugs wrong though so the first check for every new repair job on an item where there was a rewireable plug was to open the plug and make sure it was fitted properly, safely and had an appropriate fuse.

There were a rather shocking (intended) number that were dangerous, wires stripped back too far so conductors were exposed, fuses wired out or wrapped in aluminium foil, 15 amp fuses for a device that only needed a 3 or even a 1 amp fuse, wires splice by twisting together and 'insulated' with sellotape, loose screw terminals, no strain relief, all sorts of horrors.

But the plugs that go into the wall rather than the appliance are impossible to put in the wrong way because of the earth pin (real or fake) needed to open the gates for the other pins to go in. An exception: when I was ten and used to stick a screwdriver into the earth hole to open the gates...I forget why.

I have to say that even though I lived in the US for nearly half my life, I still find the electrical system scary as hell. Plugs can hang halfway out the socket exposing the prongs. They get bent easily. Indeed, they so feeble you can squeeze them together. The only "good" thing is that if you can't be arsed to get up and walk to the plug to remove it, you can just give the cord a damn good tug

[TerraHertz]

I have a broken keyboard that I'm dealing with:

 Iwould fixit ut tislap top is my only computer soI have todeal with it.

Every sentence I typecomesoutlike this and I have to go back andfix all the mistakes and sometimes miss thesubject line because it doesn't make the red lines.

So, intermittent space bar, L, G, B and H? (I'm surprised the T is working.)
I can believe 'only one computer' (barely), but no spare USB keyboard? Still? That really stretches credulity.

Frustrating to read isn't it?

Yeah, and not just the typos.
watch?v=zXT_IOt81Xs

[james_s]

I have to say that even though I lived in the US for nearly half my life, I still find the electrical system scary as hell. Plugs can hang halfway out the socket exposing the prongs. They get bent easily. Indeed, they so feeble you can squeeze them together. The only "good" thing is that if you can't be arsed to get up and walk to the plug to remove it, you can just give the cord a damn good tug

The plugs aren't the best design in the world, but they do work reasonably well and you can get good quality plugs with sturdy prongs if you're willing to spend a bit of money. The really good ones are hospital grade, you'd just about have to be He-Man to bend the prongs together on one of those. Yes you can have a situation where there are exposed prongs, but electrocution from that is quite rare. Most electrical injuries come from kids poking conductive objects into receptacles or light sockets, or people working on stuff they shouldn't be working on.

Now the NEC requires tamper resistant receptacles that have shutters, I suppose they'd be good in a house with small children but I don't like them personally. It's hard to get some plugs in, it's hard to probe them with a multimeter, and they cost a lot while mostly being cheaply built.

[Zero999]

I do like polarised mains connectors. Although a correctly designed appliance should be safe to use, irrespective of the polarity of the mains, in practise, many appliances are safer connected one way, than the other.

So you assume your appliances to be incorrectly designed, but trust their mains plugs to be correctly installed? Hmm...

No I didn't assume the appliances are incorrectly designed. An appliance can be designed to conform with all the relevant standards, yet still be safer when connected one way round, than the other. For example, in a class 2 appliance, it's normal for only one conductor to be switched and it will be safer if it's the phase conductor, rather than the neutral. The appliance is safe and conforms to the standards, but it would be safer when connected in one polarity, rather than the other.

[apis]

I have to admit I like the UK plugs. Polarised with a little fuse holder, and you have to unplug the cable to access the fuse.

The European earthed plugs does allow for a polarised socket (thanks to the hole in the earthing connector), although the sockets we have are not polarised.

In theory there is no reason we couldn't gradually upgrade to polarised (fused?) sockets though. I wonder if someone was thinking that when they designed that plug?

[Twoflower]

The hole is used by the french sockets. They have a pin sticking out and no side contacts. So they rely on that contact.

[Kleinstein]

The plug shown is a kind of compromise. The more common outlets (e.g. those used in Germany) use the outer contacts for PE and can thus be used both ways around and swap L and N.  The older French / Italian system used the extra pin for PE and were thus polarized - at least in theory.
So it is more like a way back that they can use these plugs in both types of outlets. Still I see no tendency for other countries to change to the polarized outlets.

The US plugs are rather scary: I remember a case where a piece of steel wire fell in top of the plug in the outlet, just in the small gap at make a good contact and short.  There were similar ones in Germany - but those got phased out by about 1930 for a good reason.

[Zero999]

I have to admit I like the UK plugs. Polarised with a little fuse holder, and you have to unplug the cable to access the fuse.

The European earthed plugs does allow for a polarised socket (thanks to the hole in the earthing connector), although the sockets we have are not polarised.

In theory there is no reason we couldn't gradually upgrade to polarised (fused?) sockets though. I wonder if someone was thinking that when they designed that plug?

The only disadvantage with UK mains plugs, is they can be painful when one stands on one barefoot.