Correct. That's a requirement of the electrical code, but why that is, I can't say that I fully understand. All of the neutral wires connect to the neutral buss in the main panel, and that neutral buss gets connected to ground, whether it be a plumbing pipe or a ground rod pounded into the ground outside your house.
Notice each pair of your 6 wires is connected at the insulator so although there are 6 WIRES ther are only 3 THREE conductors
Please before you demonstrate your ignorance and confuse people who admit they dont know, go back to shcool. :-?
If you had any understanding of electricity you could understand that the GROUND is not part of the circuit. It is there to keep all the parts of the system at the same reference potential.
A 3 phase Delta system requires only 3 wires. A 3 phase Wye system has 4 wires to allow connection to the center point and one phase to get a lower voltage than that between any 2 phases but a symetrical 3 phase load of the correct voltage only needs
3 wires.The ground is only for safety and is, by code, connected to the neutral at each customer.
The USA system delivers only ONE 240 volt supply to houses and the neutral is really only a centre tap of that to get 120 volts for small appliances.
I know there are variations (too complicated to explain here) but the overall principle remains.
The ground wire plays no part in a proper fault free system. No current flows in around or thru the ground if all the conductors are installed to code. :-Z
John:
In here, we all learn from each other.
None of us knows everything, but all of us know some things. We collectively share what we know so that we're all better off for it. That's how we get along.
Thats OK and I respect it But we do not need people who do not know what they are talking about spreading rubbish.
Ask questions by all means but leave out talking about things unknown as though you are the expert.
In this particular thread there has been so much ignorance portrayed as fact I thought it needed some correction. :-?
Constructive criticism is always welcome in here.
"Danny D'Amico" wrote in message news:l6n8jv$hs3$ snipped-for-privacy@solani.org...
Your panel is ABABAB...AB from top to bottom, on both sides of the breaker panel (left/right). The example given in your .png showed AB....AB on the left, and BA....BA on the right. This is a lay-out that makes zero sense and would require some goofy bus work to accomplish. If you look at your breaker mounting points you will notice that every other bus tab, from top to bottom, is the same. So, the top two bus tabs, inline from left to right are phase A. The next row down will be phase B, inline from left to right. A 2-pole breaker will take up two spaces, top to bottom and will give you both an A and a B phase. A 2-pole breaker mounted to its right will pick up the same bus tabs as the first breaker, but, of course, it will be to the right of the first circuit breaker. Just look at the two breakers that currently exist at the top of your panel. They are end to end with their operators (handles) moving in opposite directions to achieve the same action. Yet, the wiring is the same for both breaker, top to bottom. Meaning that if you where to have black and red wires denoting phasing, the black would go on A, and the red would go on B. This is a universal construct in electrical work. Black is always A, Red is always B, and if three phase, blue would be C. A three phase Delta would replace the red with an orange, denoting the fact that the system is Delta, and that the B phase to ground is a high leg and is not 120v and is not to be used for 120v circuits.
Colors are important!
I worked in a 240 Delta panel once that was phase taped for a Wye connection. Black, Red, Blue. I needed to move a single pole breaker down one slot to install a 3 pole breaker. There was a single pole breaker at the top of the panel, on that side, so this put the breaker I had to move down onto the high leg. I did not notice this and since my boss just said hurry up, get it done, and lets get out of here, I did not check the voltage. Well, someone went into the bathroom and the fart fan ran really fast for about
10 seconds before it went up in a puff of smoke and the incandescent lamp was really bright, too. Until it blew up. Never take anything for granted for when you do so, you or someone else might get hurt.
It is called parallel conductors. Two smaller cables take the place of one large cable. Cost less, and carries a higher current since the cross section of the smaller conductors cools more readily in open air than one large conductor would. Both ends terminate, respectively, at a single point. There are rules for this, too, but that is another topic.
Most generators have at least one set of parallel conductors inside, and have, usually, three sets(or more) going to the distribution bus of the power plant. Depends on voltage, of course, and not all generators are the same, so there are differences.
This is correct. My issue with the example provided was that there were an A phase and a B phase shown, inline, left to right. I have yet to see a panel with this layout. Even with three phase panels, the layout is A, B, C. Top to bottom, identical on both sides of the panel. The only deviation that I have seen is when the bus tabs are used for the main breaker input, and this only causes the loss of two connection points in the panel. This is a very common practice in MCC distribution panels. So, 22 circuits... :-)
I meant to state load center, not distribution panel. Might as well quit before the brain keeps a fartin'.
I agree with 99% of the above, except the last sentence. You will have some very small portion of the current flowing through the ground. Take for example the simple case of the neutral and ground of a 240/120V service being tied together at the house and at the transformer. Those are two paths for current to flow, just like two resistors in parallel. The vast majority of the current will flow in the neutral conductor because of it's low resistance. Some small amount, however will flow in the ground path, with it's higher resistance.
So it's 2-phase?
From Professor Cardell's web page at
"There are two wires running out of the transformer and three wires running to the house. The two from the transformer are insulated, and the third one is bare. The bare wire is the ground wire. The two insulated wires each carry 120 volts, but they are 180 degrees out of phase so the difference between them is 240 volts."
What needs to happen in here is for people to realize that talk about three phase delta and wye circuits may be interesting, but it's noise in here. We DIY'ers recognize that there is three phase power available for equipment that uses it, but it's not something that we need to know about, interesting though it may be. And, while I appreciate the input from the professional electricians in here, we all know that our brains are excellent housekeepers and that what we don't use will soon be thrown out to make room for stuff we will use. Three phase power, and how to wire it is something my brain is just itching to throw out. It needs the space for stuff it will use, like how to fix a fridge or spread drywall joint compound smoother.
nestork has brought this to us :
You are of course correct but lots of people who know very little or just enough to confuse themselves keep dragging PHASE into discussions about houshold electrics. The normal houshold supply in the USA is ONE phase with a centre tap grounded to produce 120 volts above ground and 120 volts below ground or 240 volts between the ENDS :/
I guess the IEEE and it's power engineer members must be among those knowing very little or just enough to confuse, because they clearly speak in terms of two phases being present.
From a paper presented at a recent IEEE power engineering conference:
"Distribution engineers have treated the standard "singlephase" distributio n transformer connection as single phase because from the primary side of t he transformer these connections are single phase and in the case of standa rd rural distribution single phase line to ground. However, with the advent of detailed circuit modeling we are beginning to see distribution modeling and analysis being accomplished past the transformer to the secondary. Whi ch now brings into focus the reality that standard 120/240 secondary system s are not single phase line to ground systems, instead they are three wire systems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the secon dary phases are separated by 180 degrees instead of three phases separated by 120 degrees. "
It could not be any more direct and to the point.
Further, the standard 120/240 secondary is different from the two phase primary system in that the secondary phases are separated by 180 degrees instead of three phases separated by 120 degrees.
What all of this means is that analysis software and methods must now deal with an electrical system requiring a different set of algorithms than those used to model and analyze the primary system. This paper will describe the modeling and analysis of the SINGLE-PHASE center tap transformer serving 120 Volt and 240 Volt SINGLE PHASE loads from a three-wire secondary.
It is interesting that you snipped the last Paragraph which says SINGLE PHASE twice.
How clear is that? :-?
John, we all understand that, but since the two 120 VAC sine waves coming into the house are 180 degrees out of phase with each other, it's natural to think of it as two phase power. Maybe it's not, but thinking of it that way helps us understand our house's electrical panel and the wiring coming out of it, and that's really the goal for most DIY'ers.
This "ground stake" is right below the panel, driven into the ground:
I *knew* they were all hot wires! You have to notice the smiley sign at the end the sentence.
I've previously said that there is three phase (120 degrees out of phase) transmission and distribution, so, it's clear that I knew they were hots.
I happened to go to lunch with friends in San Jose and I saw the 6 wires, and I thought of this discussion, so I snapped a picture of the 6 wires, to show the team.
I do agree with you wholeheartedly. The GROUND is the conductor back to the power plant (theoretically anyway). Clearly the wires I snapped are three phase wires, and clearly the six wires are all are hot.
The insulators were gorgeous but the distant picture cropped doesn't show how beautifully they shone with iridescent greenishblue colors.
Hi Nestork & John,
The problem is my fault. I was making a joke, but, even with the smiley, nobody got the joke.
I always tell my grandkids that if nobody gets the joke, then it's the fault of the jokester.
So, while the 6 wires did look pretty, we all know they were all hot wires. I didn't think anyone would think otherwise, so, that's why I snapped the picture and posted it.
It was just to point out that you *can* have six wires; but, they're all hot in this case!
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