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

[Stonent]

I was learning about Triacs today and the example was how to use a battery to control AC "mains" current using one.  They even specifically say to make sure the battery is sharing a terminal with the neutral side only and not the other way around.



 

Why do people even consider trying to get anywhere near working with household current if they don't know how to tell live from neutral?

[mcinque]

Well, I think because they don't minimally know what kind of effects their actions could have... Probably they ignore what they have on mains: "it's just a couple of volts and amps more than a car battery" 

[Bored@Work]

 :palm:

Why do people even consider trying to get anywhere near working with household current if they don't know how to tell live from neutral?

Why do you spend time reading such stuff? I mean, just at first glance you see that it is not worth reading. Stupid manga superpower figure. Use of "..". And the third strike, use of "???". NEXT.

[Hypernova]

Just relax, sit back and let Darwin work his magic.

[rob77]

Just relax, sit back and let Darwin work his magic.

+1 probably we'll be reading a nice story about it on the 2014 Darwin awards  web

but joking apart... those kids are just stupid    they are arrogant and they just ignore the danger. i hope those kids will not kill or injure themself during the "experiments" with mains.. but i hope they will experience a decent bang and magic smoke which will teach them to have a decent amount of respect.

[snipersquad100]

I wonder if people release magic smoke like caps.

[rob77]

I wonder if people release magic smoke like caps.

sure they do it's all about the amount of beans they consume fortunately that magic smoke is transparent

[Kjelt]

You can argue the other way round, any circuit where it is vital that phase and neutral are known and it is unsafe when connected the other way round is just piss poor design with so many countries having a symmetrical poweroutlet system where you can not be sure what the phase and neutral are without measuring and marking it.

[retrolefty]

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?

[fubar.gr]

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.

[retrolefty]

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?

[Zero999]

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

Most 240VAC countries distribute the low voltage power as 415V three phase with most domestic consumers only get neutral and 240V phase.

[mtdoc]

In the US, 240V residential power uses 3 wires:  L1, L2 and Neutral.  The neutral is usually bonded to ground (earth) at the service entrance.  240V between L1 and L2.  120V between L1 or L2 and Neutral.

[mcinque]

In the EU (and any where else) do they actually connect one side of the 220 to ground at the service panel?

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.

[Bored@Work]

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?

The American split-phase system is rather unknown. It is actually a single phase system. Depending on who you ask, either the three phase TN-C-S or the  three phase TN-S system is the most common in Europe.

In both cases you get three phases L1, L2, L3 plus separate N and separate PE at your house distribution panel. The difference is that for TN-S the N and PE are only connected at the power source (transformer) and from there on carried separately. While for TN-C-S the N and PE are one combined wire (PEN) coming from the power source. At some point during the transmission (e.g. late at the service cut out) PEN is split into a separate N and PE.

PE is earthed at a central point in the house, where also the water and gas piping is connected to.

[retrolefty]

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

Most 240VAC countries distribute the low voltage power as 415V three phase with most domestic consumers only get neutral and 240V phase.

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

[retrolefty]

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?

The American split-phase system is rather unknown. It is actually a single phase system. Depending on who you ask, either the three phase TN-C-S or the  three phase TN-S system is the most common in Europe.

In both cases you get three phases L1, L2, L3 plus separate N and separate PE at your house distribution panel. The difference is that for TN-S the N and PE are only connected at the power source (transformer) and from there on carried separately. While for TN-C-S the N and PE are one combined wire (PEN) coming from the power source. At some point during the transmission (e.g. late at the service cut out) PEN is split into a separate N and PE.

PE is earthed at a central point in the house, where also the water and gas piping is connected to.

Schematic drawings of these different systems (including U.S.) might make it all clearer?

[mcinque]

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.

[fs]

Schematic drawings of these different systems (including U.S.) might make it all clearer?

https://en.wikipedia.org/wiki/Earthing_system

[retrolefty]

Schematic drawings of these different systems (including U.S.) might make it all clearer?

https://en.wikipedia.org/wiki/Earthing_system

Thanks you for that.

[SeanB]

That socket is a recent addition, and is typically only used for double isolated equipment, like phone chargers and other 2 pin devices. You only get the earthed version in a wall outlet version that also includes the regular 16A 3 pin outlet as well, and I have never seen an extension cord for that that is not integral to equipment or is only for double insulated equipment. As well it is mandatory on all installations to have earth leakage protection on all socket outlets, irrespective of age. You can have a house with fuse wire on the board and a small box with the earth leakage breaker next to it, 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) and you still have the original 5A and 15A outlet sockets and nothing added over the years. Any new stuff has to comply with current standards.

[IanB]

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

Every country has different systems. In the UK a 240 V socket in a house has L, N and E connections. Live has 240 V on it relative to Earth. Neutral and Earth are bonded where the supply enters the house and Earth is bonded to all water pipes and gas pipes and other exposed metal fixtures. There is a low impedance return path from L to E such that a short circuit between them will blow a fuse or trip a breaker.

[FrankenPC]

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?

The American split-phase system is rather unknown. It is actually a single phase system. Depending on who you ask, either the three phase TN-C-S or the  three phase TN-S system is the most common in Europe.

In both cases you get three phases L1, L2, L3 plus separate N and separate PE at your house distribution panel. The difference is that for TN-S the N and PE are only connected at the power source (transformer) and from there on carried separately. While for TN-C-S the N and PE are one combined wire (PEN) coming from the power source. At some point during the transmission (e.g. late at the service cut out) PEN is split into a separate N and PE.

PE is earthed at a central point in the house, where also the water and gas piping is connected to.

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

[IanB]

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.

[retrolefty]

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?

The American split-phase system is rather unknown. It is actually a single phase system. Depending on who you ask, either the three phase TN-C-S or the  three phase TN-S system is the most common in Europe.

In both cases you get three phases L1, L2, L3 plus separate N and separate PE at your house distribution panel. The difference is that for TN-S the N and PE are only connected at the power source (transformer) and from there on carried separately. While for TN-C-S the N and PE are one combined wire (PEN) coming from the power source. At some point during the transmission (e.g. late at the service cut out) PEN is split into a separate N and PE.

PE is earthed at a central point in the house, where also the water and gas piping is connected to.

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

 The important difference is that neutral is a current carrying conductor, where as PE does not carry any current until a fault condition arises.