This only really works if the same wires on the circuit are crossed at the breaker. Otherwise, reversed continuity would trip the breaker. This is hardly a "minor detail" even in France.

Pardon me if I might have confused my question, I am not suggesting a short from the active to the neutral, but the way the wiring might be done. For instance rewiring a plug on an earthed appliance to suit another type of outlet socket. What if the plug has the active wire screwed into the neutral, and the neautral into the active side of the plug. The AC current would stil flow through the appliance, but I am wondering if there would be any safety implications with doing this (if any at all) ?!?

Normally it is recommended to have the active wire going to the right pin on the plug (looking at the face of the plug), and the neutral going to the left pin. The earth goes to the third pin which is bellow the other pins on most styles of plugs.

Any thoughts on this ?

Cheers, Mike

As an example, with an Edison type light socket (ie. regular light bulb socket) the threads are supposed to be connected to the neutral and the hot is connected at the very bottom of the socket. There is a greater chance of you accidently touching the threads while you are replacing the light bulb, than slipping and sticking your finger right to the bottom of the socket. So, if the threads were hot, you'd get zapped.

That's just one example where the safety is compromised a little.

Think of it this way. Electiral power flows from wall outlet, through switch into device, does some work and then flows back into the wall outlet. Your now have a complete circuit.

Switch are designed to cut the hot wire. When the switch is opened, power from wall goes as far as switch and stops. It does not enter device and the device will not work. If you open up the device and poke around in it you won't get zapped because there is no current in it.

If the wires in switch is reversed and it is opened, the power goes through the switch into device but cannot go back to the wall (since the neutral is opened). The device will still not work just like before. But if you open up the device and touch the inside you'll get zapped. Because now the device is energized and the current is looking for a way to go back to ground, in this case through you.

This is the main reason for a polarized plug - the plug with one blade bigger than the other. It is to ensure the switch always cut the hot wire.

Let's start over. If I understand correctly, the standard current in France is 220 volts, 50 cycles. Now, let me discuss how 220 outlets are wired in the US. The supply line has four wires, red, black, white and ground. The red and black are hot. There are specific locations for the neutral and ground on the receptacle. Regarding the red and black, they go in the remaining two hot lugs and it doesn't really matter in which order they are attached. It does not effect the polarity. However, if I were to wire a neutral on a hot lug and a hot on the neutral lug, now I have reversed polarity and the breaker would immediately trip. So, if I understand your premise, the order of the wiring does not effect the operation of the appliance as long as you did not reverse the polarity.

texasredhead,

From what I understand, the 220 volts in France is the hot to neutral voltage, not hot to hot like it is in North America.
So the poster is enquiring about the effect of switching the hot and neutral wires in a recepticle. In North America, it is the equivalent of putting the white wire on the gold screw and the black wire on the silver screw in a standard 120V outlet.

And your description of the 220V outlet in the US is actually a description of a 120/240V outlet. 240V outlets don't require a neutral.

Swapping hot and neutral used to be a lot more dangerous.
Some appliances had one side connected directly to chassis.

It is not as much of a hazard anymore since this method is prohibited.

Many items now have 'soft' power switches that only control a relay (mechanical or electronic switch). Some portion of the equipment has line voltage applied all the time.

Since AC voltage reverses 60 times a second (50 in some places) the actual devices rarely care about the direction.
Many of the rules are in place to provide consitancy in installations and safety for anyone who needs to work on the equipment.

Long ago, in cheaper TV sets and radios which did not have power transformers, parts of the "chassis" were used as one conductor. The chassis was intended to be connected to neutral, usually by means of a polarized plug. If the chassis was for any reason connected to the ungrounded conductor (hot wire) and one of the control knobs was missing, the exposed brass shaft could well have line voltage awaiting anyone who touched that shaft. The radio or TV typically would work OK. Reversing conductors can have deadly consequences.

I'd like to state the question another way.

Ok, standard 110v outlet. One hot (black), one white
(neutral), one bare (ground). Black goes to the copper
screw, bare goes to the green grnd screw. White goes to
the other screw (I forget what color it is).

Let's say for some oddball reason I wire the outlet
with the white wire to the copper screw, and the black
wire to the other screw. Swapping the two wires.
I do know better, so please don't flame me for it :o)

If I plugged a lamp into this incorrectly wired outlet,
the lamp would still turn on and light up. (incandescent bulb).
But what about other things I could plug into this outlet.
I think the original poster is wanting to know the consequences.
And not for back in the day of common chassis grounds.
But in today's world of double insulated tools and such.

Is this what the original question was about?

Pooh Bear

Poohbear,

A light is a good example - the older style table lamps etc often had metal lamp holders, weren't the outside with the threads, directly connected with the screw part of the lamp? That'd be a perfect example of the danger of reversed connections, or any lamp holder where the thread is exposed, since the button on the end of the bulb is supposed to be active, were this reversed, the threaded part would be active and exposed to the touch.

You're right, though, in many cases it'd go unnoticed with double insulated tools etc.

My FIL and I rewired a travel trailer he bought, it was built in the 70's. The one outlet it had in it, was wired in reverse. Since I'd been working on it and had replaced the supply plug to the trailer, I was worried I'd messed it up, but the wires on the outlet were clearly the wrong way. Unless the previous owner had messed around with it, it'd been that way since day one, and, presumably had fried no-one.

Still, I'd never allow a fault like that to remain, it's just too dangerous. You or I might know this or that outlet was wrong, but the next guy might.

My BIL had an extension cord I went to plug in and was lucky I didn't grab the other end, because, for some silly reason. he'd wired it with a plug either end!

The neutral screw on a receptacle is stainless. Regarding the travel trailer, the receptacle only worked if it was plugged into an external source presumably wired correctly. Older receptacles did not have the larger slot for the neutral so it would seem that if an appliance such as a coffee maker was plugged into this cross wired receptacle it would probably work as the coffee maker might not care which direction the current was flowing.

"My BIL had an extension cord I went to plug in and was lucky I didn't grab the other end, because, for some silly reason. he'd wired it with a plug either end!"

I'm sorry, but that's just plain STUPID to wire up an extension cord with 2 male ends.

"But in today's world of double insulated tools and such."

Many double insulated tools do not even have polarized plugs.
To be double insulated requires neither the hot nor neutral to be able to come into contact with the user.
Everything that could be energized requires covering with an insulation material.

Double insulated tools are n ot reqruied to have a grounding plug either. This cuts both ways however.
If you drill or saw into a live wire the tool can become energized through the bit or blade, and without the safety ground present the OCD will not trip.
The grip of the drill will protect you from the tool wiring, but the chuck could still be energized from an external source.

Light bulbs (incandescent) and heater elements are pure
resistance loads. Hot-Neutral direction doesn't matter.
Can anyone name a type of load that does matter.
What could be plugged into the afforementioned theoretical
receptacle that the "polarity" would matter.

I'm still having a hard time grasping the term "double insulated".
Why would the circuit ever have any reason to come in
contact with the case. I wouldn't want to touch that tool.
"Single insulated" I can understand.
But what's double about it. I think it's marketing hooey.

Some potential Darwin Award candidates will put a male end
on both ends of an extension cord to hook a generator to a house.
Plug one end of the cord into the generator,
plug the other end into a receptacle in the house.
As code challenged as I am, even I don't recommend doing this.

Pooh Bear (aka Fluff for Brains)

I'm still having a hard time grasping the term "double insulated".

An appliance which is double insulated has the whole of the inside contained in plastic, underneath an outer casing.
If anything goes wrong with the appliance, no live conductor can touch the outer casing because of the insulating plastic.

Why would the circuit ever have any reason to come in
contact with the case.

Basically, if something shorts out in the appliance and causes a wire to come loose.

The majority of my power tool inventory is from Sears, with aluminum housing. Old stuff, parts often unavailable. But they are NOT double insulated. The insulation on the conductors inside is all that stands between that housing and the full line voltage. That is single insulation, although that term was never officially applied to those tools. The housing on some is grounded by the green conductor in the cord and the third prong on the male plug. But some of them predate the grounding plugs. Retrofit is possible.
With double insulated, any conductor has not only the insulation on that conductor but also the non-conductive housing (inner or outer) surrounding those conductors. I hope this adequately explains the double insulated concept.

That explains it for me very nicely.
Thanks. Learned something new today.

Pooh Bear

Thanks for the lively and interesting discussion ! It seems I've gotten my answer from what were a few comments regarding consistency of work. Without any more specific examples, the "lamp" example with the Philips (or bayonet) receptacle was the most simple and obvious problem of causing grave danger to persons changing a simple light-bulb. It actually reminded me of an old lamp with the bakelite receptacle cracked (as bakelite has a tendency to do after many years) and the outer thread of the bulb receptacle became partly exposed. I grabbed the receptacle to change the bulb without hesitation, as one would out of pure habit, touching the exposed metal at the same time. If the hot and neutral on the socket outlet had been wrongly wired I would have surely been zapped and possibly killed by such a simple action - all because somebody decide it wasn't relevant whether the hot and neutral wires became swapped over when changing the outlet over or something ... This offcourse never happened, but it's a realistic scenario.

I was hoping there might have been something more specific with today's modern gear but it looks like double insulation etc has now made it safer for such potential accidents (if they should occur). The reality is probably that one can never guarantee what type of gear (and how old) might be plugged into an outlet socket, and for consistency's sake it seems like a good idea to just stay smart and stick with the rules of keeping all wiring colours and recommended connections matched as per instructions rather than making assumptions or just being slack about any DIY electrical work, especially in older holmes or gear ... with regards to having an extension cord with two male plugs on each end, now that's just plain dumb regardless of voltage, country or sexual orientation ... Thanks.

Cheers, Mike

One aspect not mentioned is electromagnetic fields, it seems about once a decade there's some news hype of EMFs causing disease. I remeber in the 70s seeing people worried about the EMFs from electric blankets when not running. I remember it was a marketing point(ploy) for the blanket manufacturers to wire them with polarity to so no line voltages were present in the blanket when it was off to prevent EMFs (besides the other obivous safety advantages). So if you reversed polarity of your plug your electric blanket would be creating EMFs, even when off.

"If the hot and neutral on the socket outlet had been wrongly wired I would have surely been zapped and possibly killed by such a simple action."

Not very likely really. You still need to complete the circuit from hot to ground or neutral to be shocked.
If you are not touching something that is grounded you can touch a hot and nithing wil happen.
Ensuring you have not missed ANY path to ground is the problem in a non-controlled environment.
Remember that even a metal lamp shaft is not normally grounded.

Most dangerous situation I have seen as a result of reversed wiring:

Someone reversed hot and neutral at a junction box in a two-wire (no ground) system, then proceeded to wire in grounded receptacles using a bootleg ground at each (jumper from neutral screw to ground screw). This of course made the ground hot and energized the metal case of any grounded appliance plugged in. Surprisingly, I have seen this on two separate occasions in the last 10 years.

My code 1 teacher last semester described that exact situation. Combine 2 wiring errors like reversed polarity and bootleg ground and wind up with a deadly installation. That would be a lot of fun in a basement with a concrete floor or a grounded appliance while touching the metal plumbing. Glad a lot of inspectors are carrying along a suretest receptacle tester that can catch shotty workers flipping a house and bootlegging the receptacles.

In a similar situation to that mentioned by normel, when portable power tools started to be equipped with three conductor cords and grounding plugs, several folks in my area decided that since the neutral is grounded anyway, proper grounding could be achieved by installing a grounding jumper inside the tool from the metal tool housing to the white conductor of the supply cord. The plug was left as is, unpolarized. Almost like Russian roulette with a cartridge in every other chamber. Being imaginative to the point of ignoring basic electrical safety rules is very unwise.

One question hasn't been answered yet.

What device could I possibly plug into this theoretical
outlet that the "polarity" would matter.
I'm not asking from a safety standpoint, but rather would
it hurt the device or cause it not to function.

I recently wired an electric motor. The directions
showed L1 went to hot and L2 went to neutral. The motor
frame was grounded. I wired it to these specs.
What would happen if I plugged it into the
afformentioned incorrectly wired outlet.

Just curious.

Pooh Bear

One aspect not mentioned is electromagnetic fields, it seems about once a decade there's some news hype of EMFs causing disease.

You're more likely to die from worrying about EMF than from any real ill effects. But to make people feel more secure, most electric blankets and similar appliances now have paired wires so that the fields cancel out.

the blanket manufacturers ... wire them with polarity to so no line voltages were present in the blanket when it was off to prevent EMFs ...

Sorry, this makes no sense at all. If the blanket is off, no current is flowing, no EM field is produced.

"I recently wired an electric motor. The directions
showed L1 went to hot and L2 went to neutral. The motor
frame was grounded. I wired it to these specs.
What would happen if I plugged it into the
afformentioned incorrectly wired outlet."

It would run exactly the same.

Thanks for that info.
I had to put a plug on the end of the motor cord
and I made sure L1 went to hot.
Didn't know if it made any difference,
but figured it was best to go with what the directions said.

Thanks.

Pooh Bear