Can't tell live from neutral, but wants to build 220V circuits.

[nitro2k01]

But is that neutral bonded to ground at the service connection? If not it would be better named common rather then neutral.

No. AFAIK any metal chassis it's only and mandatorily connected to the earth ground.
You must take in consideration that only here in Italy and in South Africa we're so "smart" to use a socket that can be reversed. A MAN cabling would be a trouble.

we do not bond to ground neutral, because we have reversible plugs: with the wrong orientation of the plug in the socket, we would bring the live on the metal chassis of our devices.

I think you've misunderstood. See the above posts. Neutral and protective earth are not connected in the plug, but down in the distribution panel. PE normally doesn't carry current, and if you have a fault, the RCD will trip. The German schuko plug, probably used in half of Europe, is also reversible and works like this.

And even if this weren't the case, how would a wrongly inserted plug translate to any danger? Let's assume one of the conductors was connected to the ground in the distribution panel (neutral) and this conductor was connected to the center hole and one of the other hole. This is what they did in Soviet and it's not optimal, but it more or less works. The chassis would always be connected to the center pin which would always be connected to the "safe" wire in the outlet. Reversing the plug (which would have to have 3 wires.) would reverse the polarity of the voltage supply to the machine, but never connect the chassis to live.

[kolbep]

SeanB,
With the recent changes to SANS10142 (ADMT , you can have a loophole on Insulation Resistance tests , just get the customer to plug a Computer or Medical Device into the socket, then make use of the following loophole :

Insulation Resistance Testing:

NOTE 2 In the case of existing installations where the power may not be switched
off from certain circuits in order to carry out this test, the fact that the circuits are
subject to the supply voltage can be regarded as evident that the insulation
resistance is compliant. Amdt 8
----

But to anybody that wants to exploit a loophole like this, remember, it is your a*se if you pass the compliance, and a fire breaks out, or if somebody gets killed because you took a shortcut. And anyway, if you do the proper testing :
1) You can be sure that the Insulation Resistance is good, or
2) You have a business oppertunity to make money replacing the cables

and it will be passed so long as the wiring still meets minimum insulation levels ( good luck doing that with 50 year old DCC wire though, there you will rewire in all probability)

[rob77]

But is that neutral bonded to ground at the service connection? If not it would be better named common rather then neutral.

No. AFAIK any metal chassis it's only and mandatorily connected to the earth ground.
You must take in consideration that only here in Italy and in South Africa we're so "smart" to use a socket that can be reversed. A MAN cabling would be a trouble.

we do not bond to ground neutral, because we have reversible plugs: with the wrong orientation of the plug in the socket, we would bring the live on the metal chassis of our devices.

I think you've misunderstood. See the above posts. Neutral and protective earth are not connected in the plug, but down in the distribution panel. PE normally doesn't carry current, and if you have a fault, the RCD will trip. The German schuko plug, probably used in half of Europe, is also reversible and works like this.

And even if this weren't the case, how would a wrongly inserted plug translate to any danger? Let's assume one of the conductors was connected to the ground in the distribution panel (neutral) and this conductor was connected to the center hole and one of the other hole. This is what they did in Soviet and it's not optimal, but it more or less works. The chassis would always be connected to the center pin which would always be connected to the "safe" wire in the outlet. Reversing the plug (which would have to have 3 wires.) would reverse the polarity of the voltage supply to the machine, but never connect the chassis to live.

actually the CEE 7/5 socket is used in half of the Europe - it has 2 variants CEE 7/5 type F (German Schuko) and CEE 7/5 type E (French). but all the new plugs are made compatible with both type E and F sockets.
advantage of type E (French) is the fact the plug can't be inserted reversed like with type F (Schuko) socket.

[GeoffS]

In Australia, the neutral is connected to ground at the premises switchboard (service panel)
Earth is a large metal stake in the ground somewhere near the switchboard although in  older houses it may be connected to the water pipes.

[FrankenPC]

What's the exact difference between N and PE?  A slight difference in impedance characteristics?

PE is not supposed to have any elevated voltages on it. The neutral wire carries current and therefore will experience a voltage difference along its length. The earth wire must not carry any current in normal operation and therefore remains very close to ground potential.

Ah!  Ok.  It's literally THE potential path at all times VS PE which should only be intermittent under ideal conditions.  Makes sense.

[Lightages]

No. AFAIK any metal chassis it's only and mandatorily connected to the earth ground.
You must take in consideration that only here in Italy and in South Africa we're so "smart" to use a socket that can be reversed. A MAN cabling would be a trouble.

We use that same idiotic plug here in Chile too. The difference is that we also have a neutral! So you never know if you are plugged in the right way or not. I have taken to marking all my outlets and plugs to make sure they are the same. It is absolutely insane to use a system like we have here.

[deth502]

In Australia, the neutral is connected to ground at the premises switchboard (service panel)
Earth is a large metal stake in the ground somewhere near the switchboard although in  older houses it may be connected to the water pipes.

same in the us, only is many times connected to both ground rod and water pipe.

funny thing in the us, for the most part (99% of the time, there may be a few exceptions) every single phase mains line going into a residential or single phase commercial building has 3 wires. L1, L2, and the gnd/neutral. with again, nutral and ground for the household wiring connected in the box, HOWEVER, it is illegal to run a wire out of the service pannel without a separate gnd and neutral wires. even if your feeding a sub-panel, designed to take a 3 wire service cable, if it comes off of your main panel, it MUST have 4 wires.

[rob77]

In Australia, the neutral is connected to ground at the premises switchboard (service panel)
Earth is a large metal stake in the ground somewhere near the switchboard although in  older houses it may be connected to the water pipes.

same in the us, only is many times connected to both ground rod and water pipe.

funny thing in the us, for the most part (99% of the time, there may be a few exceptions) every single phase mains line going into a residential or single phase commercial building has 3 wires. L1, L2, and the gnd/neutral. with again, nutral and ground for the household wiring connected in the box, HOWEVER, it is illegal to run a wire out of the service pannel without a separate gnd and neutral wires. even if your feeding a sub-panel, designed to take a 3 wire service cable, if it comes off of your main panel, it MUST have 4 wires.

that's exactly because the ground wire MUST NOT carry current. imagine your sub-panel connected with a common neutral/ground - under load the ground in your sub-panel will be few volts above the ground in your service panel (voltage drop acros the wire) and it's not a regular ground anymore.
if you have dedicated ground wire , then the ground in your sub-panel will have the very same potential as the ground in the service panel.
the fact that there is a common ground/neutral in the service panel (or distribution panel or whatever you call it) is ok, because that point is connected to a "physical" ground - burried metal plate, pipes...etc..

[vk6zgo]

But is that neutral bonded to ground at the service connection? If not it would be better named common rather then neutral.

No. AFAIK any metal chassis it's only and mandatorily connected to the earth ground.
You must take in consideration that only here in Italy and in South Africa we're so "smart" to use a socket that can be reversed. A MAN cabling would be a trouble.

we do not bond to ground neutral, because we have reversible plugs: with the wrong orientation of the plug in the socket, we would bring the live on the metal chassis of our devices.

I think you've misunderstood. See the above posts. Neutral and protective earth are not connected in the plug, but down in the distribution panel. PE normally doesn't carry current, and if you have a fault, the RCD will trip. The German schuko plug, probably used in half of Europe, is also reversible and works like this.

And even if this weren't the case, how would a wrongly inserted plug translate to any danger? Let's assume one of the conductors was connected to the ground in the distribution panel (neutral) and this conductor was connected to the center hole and one of the other hole. This is what they did in Soviet and it's not optimal, but it more or less works. The chassis would always be connected to the center pin which would always be connected to the "safe" wire in the outlet. Reversing the plug (which would have to have 3 wires.) would reverse the polarity of the voltage supply to the machine, but never connect the chassis to live.

Yes,it is is no more dangerous than an Australian plug into a socket with the L & N inverted.
(Until the 1970s,the now standard orientation was only a recommendation,so there may be some inverted ones around,still).

In a "Single Insulated" device,it is the Earth (PE) which  is connected to the frame/chassis,not the Neutral,so inversion of L & N should have no effect.

The only exception is in the old "Transformerless" Radios & TVs used many years ago in some countries,where one side of the Mains was connected to the device chassis.
A reversal of L& N would make the chassis "hot" with respect to any earthed object,creating a shock hazard.
When new,these devices were heavily insulated to protect the user,but old ones may have lost some of this protection.

"Double Insulated" devices  do not care about L & N orientation,as their insulation is integral to the construction of the device & does not distinguish between the two Mains connections.

[ejeffrey]

In the US there is no 'neutral' on the 220 VAC circuits, just L1, L2, and a safety ground. In the EU (and any where else) do they actually connect one side of the 220 to ground at the service panel?

In the US the neutral is the center tap of the distribution  transformer which is also grounded.

Yes, the U.S. homes it's a 240 vac 'split-phase' service, but the grounded (at the service panel) neutral is not routed to the 240vac load circuits, just the 120vac load circuits get the neutral and one of the 'L' phases run to them, along with a safety ground wire.

 Again my questions was do other countries that only use 240vac load circuits, is one side grounded at the service panel?

Yes.  In parts of the world where 220-240 VAC is the standard outlet voltage one leg is neutral and the other is hot.  They don't have an equivalent of the US domestic split phase distribution, at least not for general use.

[vk6zgo]

In the USA,Amateur Radio Operators are the most likely people to have plugin equipment for 240v,as legal limit Linear Amplifiers draw too much current from the 120v supply,limiting the output to less than allowed by the FCC.
As far as I can see,most other use of the "split-phase" system is for washing maxhines,stoves,etc,all of which are either hard wired,or use a different,special socket.

[miguelvp]

Some washers, dryers, A/C units operate at 240 in the US, I have a 240 plug on the living room but never used it. It's next to a window so it probably was for an air conditioner.

It's a Nema 6-20 plug

[G7PSK]

Not sure if this is in all US states but the few that I have visited the overhead pole distribution system uses the same neutral/earth wire for both the LT and HT. This I guess is fine as long as all earth's are OK but I could see a situation perhaps due to drought where some of the earth's/grounds are not as good as the should be and therefore a somewhat elevated potential on the neutral earth line.No doubt this is where someone shoots me down in flames, but by using the same line for both sides of the transformer it effectively becomes an auto transformer, non isolated.

[rob77]

In the US there is no 'neutral' on the 220 VAC circuits, just L1, L2, and a safety ground. In the EU (and any where else) do they actually connect one side of the 220 to ground at the service panel?

In the US the neutral is the center tap of the distribution  transformer which is also grounded.

Yes, the U.S. homes it's a 240 vac 'split-phase' service, but the grounded (at the service panel) neutral is not routed to the 240vac load circuits, just the 120vac load circuits get the neutral and one of the 'L' phases run to them, along with a safety ground wire.

 Again my questions was do other countries that only use 240vac load circuits, is one side grounded at the service panel?

Yes.  In parts of the world where 220-240 VAC is the standard outlet voltage one leg is neutral and the other is hot.  They don't have an equivalent of the US domestic split phase distribution, at least not for general use.

actually we have it for general use , it's  400V 3 phase using a 4 pin plug (or newer 5 pin plugs). you will not find that one in apartments, but a lot  of houses have it to power some "heavy gear".

[Kremmen]

Yes, commonly used for e.g. freshwater pumps (wells), semi fixed power tools etc. I have in my hobby shop a 3 phase table saw, lathe, cnc mill, plasma cutter and other stuff. In the woodshed there is a bigger circular saw for cutting firewood to length and so on. All buildings have at least one 3 phase outlet on the outside wall, garage and woodshed a few inside as well. On numerous occasions it has been very practical to plug in a heavy 3 phase extension cord and a worksite outlet box on the other end. That way you can share several 1 phase outlets between the phases and run several heavy tools at the same time without worrying about overloading the circuit protectors.