Re: What will happen if a terrorist puts a current on the "ground" wire ?

| >| > | > Usually there are two wires a plus (+) and a minus (-). | | >| > | | >| > | In the U.S., one swings between + and - (the "hot" wire), | and the | >| > other sits at zero voltage (the "common" wire). That is | because | >| > residential two-phase wiring here is AC, and therefore | there is no | >| > positive wire nor negative wire. I expect that the | same holds in the | >| > Netherlands. | >| >

| >| > Nope. | >| > Europe uses 415V 3-phase and neutral 50 Hz. Domestic is single phase and | >| > neutral, 230V. There is no 110V 60 Hz here. | >| | >| Which is the same as US residential distribution, except for the voltage | >| and frequency. | >| | >Not quite. | >In Europe each home gets one phase and grounded neutral from a large | >communal transformer, but in the US each home gets two phases and | >neutral from a smaller individual transformer and the two phases are not | >clearly identified by a colour code as they are in Europe. | | In USA, homes generally get one phase of the 3 phases, not two. | Clearly false:

| Two 120V legs 180 degrees out of phase with each other comprise one | phase, not two.

Two phases out of 3 are 120 degrees apart, not 180.

Two 220V legs 120 degrees out of phase with each other comprise two phases, not one, even with a centre tap at 110V below one and above the other, and grounded.

| Just for giggles, there is such a thing (not common) as "2-phase". The | two phases there are 90 degrees apart. 2-phase and 3-phase can be | converted back and forth between each other with transformer arrangements.

Not for giggles, the starting winding of single phase motor is +/- 90 degrees from the running winding, depending on the desired direction. Usually a centrifugal switch is employed to disconnect the starting winding after the motor has started. There are such things (extremely common) as "2-phase" motors.

On Sun, 15 May 2011 18:08:20 +0100, Androcles rearranged some electrons to say:

You are mixing the definitions of split phase and 3 phase. They are different concepts.

I never stated that you could connect the two sides of a split phase together. They would be connected to a load. I stated only that they didn't need to be separately identified, becasue it doesn't matter which way you connect to the load terminals... as long as you connect the two hot leads to the load, the load will be powered by the full voltage of the phase, and not the split voltage. It is not required to identify them separately because the load will perform the same no matter which way they are connected.

I hope you are not an electrician or an electrical engineer (as I am) because you are hopelessly confused. I have worked on both US and European style distribution systems... it's clear you have not.

It depends on how well the loads are balanced. If the loads on the European three phase transformers aren't divided evenly, it's just as bad as if the primaries of the single phase distribution transformers in the US system aren't divided evenly among the three phases.

It works like that in the US as well. For a 120V circuit, black is hot and white is neutral. Don't connect the black to the white unless you like to see sparks. * About 95% of circuits in a US home will be like this.

For a 240 volt circuit with two hots and a neutral, the second hot is red. Do not connect the black and red unless you like sparks. Same for red and white.

For three phase (rare in homes), the three hots are black, red and blue.

They are, in the distribution panel and beyond.

• Special rules apply to switch loops so you don't have to have specially coded wires for switches.

| > Where I come from I can connect line to line as in red to red, yellow to | > yellow, blue to blue. I cannot connect line to neutral except through a | > load, that is single phase. I cannot connect red to yellow except | > through a load, they are 120 degrees out of phase. I'd like to see you | > connect the two hot wires of a split phase system. You are incorrect, | > since both conductors of a split phase system are actually 180 degrees | > out of phase, it is advisable to identify them separately. | | You are mixing the definitions of split phase and 3 phase.

You are incorrect. You are mincing words. Take a hint: Have a nice day.

Some US homes have 120/208 three phase Wye service. Most areas have four to six homes per transformer. Only in rural areas do you see a lot of single user transformers.

Bullshit. You know nothing about the US electrical system other that bits of crap you've found online. The loads are balanced between the phases, to minmize operating costs for the electric company.

Then you are talking a Delta configuration, not Wye.

It will be within a volt or so, as long as the neutral isn't open. They are boneded at the main braker box so the only imbalance will be due to the resistance of the netral wire between the load and the main panel.

Take a hint: You are a piss poor troll.

That's a 120V/240V "wild leg delta" configuration. It's rare now but was once used for small business with a small three phase load, with most usage single phase loads. You almost never see that for a residential service, except maybe for a very large house with a (3 phase) whole house A/C system, or a business in the home with a 3 phase load.

The typical US system has one single phase transformer, with its secondary center tapped. The center tap is grounded, and there is 120V between each end of the secondary and the neutral (center tap) and 240V between the two ends.

Go back to your incorrect diagram at

The two ends of a center tapped transformer are 180 degrees apart from each other w/respect to the center tap. For 120 degrees, you need 2 transformers from 2 phases, at minimum.

It's a single phase from 1 transformer. Any two phases of a 3 phase star/ wye service will be 208 volts, not 120V. (the typical 3 phase service is *not* that at

Two phase electrical service with the two phases 90 degrees apart was once common in the early days of electricity. They soon figured out that three phase systems transmitted more power with the same amount of copper so two phase went away. A two phase motor was wired very similar to a single phase capacitor start motor, except there was no capacitor and no centrifugal switch, and the second winding was connected to the second phase.

On Sun, 15 May 2011 20:36:17 +0100, Androcles rearranged some electrons to say:

I get it. You're one of those trolls who, when shown he is wrong, tries to deflect the argument by changing to an unrelated or irrelavent topic.

You're wrong. You don't understand electrical distribution engineering, and the sooner you come to grips with that, the safer you will be. If you do your own electrical work, I hope your house doesn't catch on fire.

Then again, maybe I *do* hope your house catches on fire, troll.

That's a 120V/240V "wild leg delta" configuration. It's rare now but was once used for small business with a small three phase load, with most usage single phase loads. You almost never see that for a residential service, except maybe for a very large house with a (3 phase) whole house A/C system, or a business in the home with a 3 phase load.

The typical US system has one single phase transformer, with its secondary center tapped. The center tap is grounded, and there is 120V between each end of the secondary and the neutral (center tap) and 240V between the two ends.

Go back to your incorrect diagram at

The two ends of a center tapped transformer are 180 degrees apart from each other w/respect to the center tap. For 120 degrees, you need 2 transformers from 2 phases, at minimum.

It's a single phase from 1 transformer. Any two phases of a 3 phase star/ wye service will be 208 volts, not 120V. (the typical 3 phase service is *not* that at

Two phase electrical service with the two phases 90 degrees apart was once common in the early days of electricity. They soon figured out that three phase systems transmitted more power with the same amount of copper so two phase went away. A two phase motor was wired very similar to a single phase capacitor start motor, except there was no capacitor and no centrifugal switch, and the second winding was connected to the second phase.

------------------------------------------------------ Michael, you and I know what is considered single phase 3 wire in North America. In the parts of the world that do not use this "Edison" system, it is often called "2 phase". That is a cause for confusion between the sides of the pond. There is justification for this on the basis that an n phase system has 360/n degree phase separation (single phase is a degenerate case).

Don Kelly cross out to reply

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IT'S A SHAME DON KELLY..THE POST IS ABOUT A TERRORIST ATTEMPT ON AN EXISTING U.S. ELECTRICAL SYSTEM AND YOU FEEL YOU HAVE TO GIVE ALL THE FACTS ABOUT SAID SYSTEM.

ITS BEEN A WHILE SINCE PROTEUS AND WEBTV BOY, BUT I SEE YOU ARE STILL AS CARELESS AS EVER.

DO YOU THINK THIS IS A SAFE MEDIUM......? TELL US SOMETHING...WHEN YOURE NOT GIVING AWAY INTRINSCIC FACTS ABOUT U.S. SYSTEMS, DO YOU STILL TAKE COVER AND PROVOKE FLAMES AND ATTACKS ON THOSE THAT CALL YOUR ATTENTION TO THESE DETAILS.

THEN YOU AND THE REST SCOFF AT THE POSSIBILITY THAT THE ENTIRE SEPTEMBER ELEVEN CATASTROPHIC ATTACK ON THE NYC TT WAS NOT A CONTEST BESTED BY HURT PROBABLY CHEATED POOR MOUNTAIN FOLKS FOOLS ABROAD....I HAVE NO SYMPATHY FOR NIETHER...NYC MAY BE RECOVERING....BUT THE BURDEN IS STILL UPON THEM THAT BROUGHT SUCH EVIL UPON MEN THAT IN GOD TRUST...HATE IS AN UNSTABLE WEAPON.......PRAY FOR THEM. WE ALL LOST SOMEONE OR SOMETHING IN THOSE DAYS.

AND CURB YOUR ENTHUSIASM...STAY ON THE WALK.

TGITM PATECUM

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I would disagree. The input box requires a feed to ground stakes at the entrance, and to water ground, when can be on the other side of the house, since it must be before the water meter. This is how the electrician wired it after removing the water pipe ground which was an extension through the house pipes. When I lived there when I was young, I was getting charges taking a shower on ground level. The water meter shunt needed tightened.

My new house is wired the same way, which was upgraded, as in my old house. The water meter is at the other end of the house from service entrance.

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This doesn't look rare to me, it looks extremely common:

You almost never see that for a | residential service, except maybe for a very large house with a (3 | phase) whole house A/C system, or a business in the home with a 3 phase | load. | | The typical US system has one single phase transformer, with its secondary | center tapped. The center tap is grounded, and there is 120V between | each end of the secondary and the neutral (center tap) and 240V | between the two ends. | In other words two phases are across the horizontal leg with the centre tap and the other two legs are absent.

| Go back to your incorrect diagram at

The problem with discarding the L3 terminal as you suggest is that it is used with L1 or L2 further up the street to keep the load balanced, so the diagram should have shown two more grounded centre taps, N2 and N3, like this:

| >| Two 120V legs 180 degrees out of phase with each other comprise one | >| phase, not two. | | >Two phases out of 3 are 120 degrees apart, not 180. | | The two ends of a center tapped transformer are 180 degrees apart from | each other w/respect to the center tap.

They are indeed.

| For 120 degrees, you need 2 | transformers from 2 phases, at minimum.

The grounded centre tap has created two transformers from one, as you can clearly connect a 110 light bulb to either one. For 120 degrees you need the third phase.

| | >Two 220V legs 120 degrees out of phase with each other comprise two | >phases, not one, even with a centre tap at 110V below one and | >above the other, and grounded. | | It's a single phase from 1 transformer.

It's two phases 180 degrees apart from two transformers wound on a common iron core.

Any two phases of a 3 phase star/ | wye service will be 208 volts, not 120V. (the typical 3 phase service | is *not* that at

The typical US 3 phase service *IS* that at

What's that? Certainly not anything common in USA homes. Looks to me like L1 and L2 are 120V from N, making L3 208V from N. Line-to-line is

And, the transformer secondary winding from L1 to L2 is 1 phase not 2, and if acting alone it provides "split phase" power like what most USA homes get.

This is explained in

That is the more-Web-documented one of two schemes that gives a "high leg". (The other is "3 phase star" modified to have five 120V lines and a

That article says this is used in shop and industrial situations where

That's not 2-phase but, as explained by someone else in this thread, split-phase. It's one phase with its center tap grounded.

Meanwhile, where are you getting 110/220 rather than 120/240?

There is even such a thing as "3 phase star". That comes from three transformer secondaries having center taps connected to each other and to neutral. It's *not* called "6-phase". It is 3 split-phases.

My experience is that motors for 2-phase power are not common. I have only seen one so far. I have seen many 3-phase ones and many more induction motors made for single-phase power.

And, 2-phase motors take 2-phase power, which is not split-phase power.

Now it comes to my attention that 3-phase-wye is sometimes called "star".

I was mentioning as "star" an arrangement that has 6 lines 60 degrees apart, as in an asterisk. I am aware of that one, so I don't like to call the arrangement with 3 lines powered by 3 transformer secondaries whose other ends tie together at neutral as "star", but "wye".

Try this instead:

Now draw its schematic, since you don't like the one I chose.

In USA, homes generally get two phases of the 3 phases, not one.

I get a photo of 3 "pole pig" transformers on one pole. My experience is that most poles having "pole pigs" have only 1. Furthermore in my experience, the "distant 2nd place" for number of "pole pigs" on 1 pole is not 3, but 2.

And, if that was used to provide multiphase power, I see most likely in "open delta" arrangement of providing 3-phase power. Only 2 transformers are needed to power L1, L2 and L3 of the scheme in

"Open delta" is not the most efficient of copper, but sometimes has cost advantage of using 2 transformers rather than 3.

to me

YOU CAN STICK AN APENDAGE INTO IT AND BY THE STRENGTH OF THE TINGLE TELL THE VOLTAGE. JUST LIKE KIDS KNOW IF A 9VOLT BATTERY IS GOOD BY LICKING THE CONTACTS. BOOWAHAHA...KIDS., WHAT AN IMAGINATION.

TGITM PS: STOP GIVING WANNABE TERRORIST IDEAS, THEY HAVE ENOUGH PROBLEMS ALREADY. BOOOWAHAHAHAHAHA OHHHHOHOHOHOHOHO NO NI NO NO BOOWAHAHAHAHAHA

STOP STOP STOP! BREWAHAHAHAHAHAHA

PATECUM (:-/

USA homes generally get what in USA is called "split phase", which is one phase of 3, from a transformer secondary that is center-tap-grounded.

As in, being powered from only 1 "pole pig" transformer secondary, as in the L1-N-L2 one of the 3 shown in

Nearby "pole pigs" powered by the other 2 phases usually have their secondaries likewise center-tap-grounded to provide "split phase" power to homes 1 block away or whatever.

Combining all 3 phases at "home service entrance level" would be 3-phase "star", as in "asterisk as opposed to wye". As in able to power 2 208- volt "delta loads" apart from each other by any multiple of 60 degrees.