But the box doesnt see them as 120 volt loads. It doesnt care.
Case 1 : if they are all connected to one leg of the 200 amp service all you can draw is 200 amps before the breaker pops with 0 current in the other leg. Yo uare only using 1/2 the box.24KW Case 2 Same as case 1 but for the other leg. Case 3 they are evenly distributed on each leg, when you do this the box no longer sees them as individual 120vac loads but sees them as
240vac load so now you have 240vac at 200amps or 48KW
AT no time were you allowed to excede 200 amps.
In case 1 the current path is 200 amps from L1 to the neutral wire. In case 2 the current path is from L2 to the neutral wire. In case 3 the current path is from L1 to L2. L1 and L2 ar across 240 vac not 120vac. In this case the 120 vac loads are in series forming
240 vac loads. 240vac x 200amps =3D your 48Kw There are no 120VAC loads as far as the panel is concerned.
No shit Sherlock. I never said anything inconsistent with that.
The operative word here is LOADS. It's plural because there are TWO
120volt loads, with a current of 200 amps flowing through EACH of them. If instead of TWO 120volt loads with 200 amps flowing through each of them, you can have only one 120volt 200 amp load, which is what you claim, then you just lost half your load capacity and the math does not add up.
You told the homeowner the service will only suipport 200 amps of
120volt load. Following your answer, he buys only 200 amps worth of
120volt eqpt and that is all he ever hooks up, drawing a max of
24KVA. You're comfortable with that answer?
Following the answer the rest of the folks in this thread know to be correct, he goes out and buys 400amps worth of 120volt eqpt, places half of it on one leg, half on the other, and he's got 48KVA. Our math adds up, yours does not. It's also not even debatable, because we all know in the real world that 200 amp service can in fact support
400 amps of 120 volt eqpt. Not a single person in this thread is arguing otherwise, except you.
And one more time, I have said the total current flowing in the service cable is a max of 200 amps.
Who cares as far as the panel is concerned? That is not the issue. The issue is how much current is flowing as far as each of the 120volt loads is concerned. The panel with 200 amps flowing can support a VARIETY OF VOLTAGE and loads. You can divide up the voltage across multiple loads any way you want. I gave you an example of how you could divide it up and get that 200 amps flowing across four 60 volt loads. You then are supporting 800 amps worth of 60 volt load.
800X60=3D48KVA and once again, we have all the power accounted for across all four loads.
Again, the simple question from the homeowner is:
What is the maximum 120volt load that I can support in my house with a
200 amp service. The answer is always the same, 400 amps. You still have not explained how the homeowner gets cheated out of half his power if he listens to your answer and only buys 200 amps worth of eqpt. Doesn't that bother you?
One more time:
------------------- 240Volts-------------- I I I I I I I---------.6ohms--------.6ohms-------- load 1 load 2
Simple, basic questions:
How much current is flowing in this circuit: 200 amps
What is the current flowing in load 1: 200 amps
What is the current flowing in load 2: 200 amps
What is the voltage across load 1: 120volts
What is the voltage across load 2: 120volts
What is the power in EACH of these loads? 120voltsX200 amps=3D 24KVA
How many amps of 120volt load is being supported? 400
How many amps worth of 120 volt heaters could I buy and hook up in this way? 400
What is the total power? 120voltsX400 amps=3D48KVA, or 240voltsX200 amps =3D48KVA.
Notice how the math ALL adds up. There is no missing power and the homeowner gets to hook up 400 amps worth of 120 volt eqpt. hust like in the real world. Following your answer the poor guy only hooks up 200 amps worth of 120volt eqpt. Where did the other half of his power and load disappear to?
You keep interchanging the meaning of current and power. They are not the same. At no time will there be more than 200 amps of current flowing in the box without tripping a breaker. It doesn't matter how you divide up the loads there will never be more than 200 amps flowing in the box without tripping a breaker. Your terminology saying 400 amps of LOAD is just wrong. But guess what I work with engineers that say it all the time. I know its wrong, they know its wrong but we all know what each other means. The OP made the same mistake and that is why I said he was asking the wrong question or was it the question wrongly.
I tried to clarify what he meant and when I got through it sounded like I was saying there were 400 amps of current flowing, my bad. I was merely trying to indicate he could still power the load he wanted and it didnt take 400 amps to do it.
Jimmie
Jimmie
Im sorry you dont get it. I suggest you get some good books on electrical engineering and try to learn more than the mechanics.
No, there is not a single physical current of 400 amps flowing. I've said repeatedly that you only have 200 amps of mx current flowing through the service. That applies to the panel as well.
Now that is simply untrue. Nowhere above have I ever interchanged current and power. But they do need to obey the laws of physics, which in ALL of the above they do. All of the current and all of the power are accounted for and there is 400 amps of current flowing across 120volt loads that accounts for the full 48KVA of power in the service. Capishe?
No shit Sherlock.
No shit Sherlock.
240 volts x 200 amps or 48000 watts. Thats the same as 120 X 400 amps. I think the OP wanted to know if he could get a total of 400 amps at
120VAC. Lets rephrase that to could he power 400 1 amp 120 VAC loads from this box under residential conditions. The answer is yes "
Then you apparently changed your mind. When called out on it, you then said " I don't know why I said that, but I was wrong." Now, apparently you knew all along why you said it, it was no mystery.
It wasn't a wrong question. It was a very reasonable question that any homeowner could ask an electrician or electrical engineer. "How many amps of 120volt load is the max that I could hook up to a 200 amp, 240volt service." You've got at least two electrical engineers here and we both say that the answer to the question of how many amps of 120volt load a 200 amp 240v service can supply is 400. You also have about 5 other people who have weighed in and they say 400. The only lonely voice coninuing to say 200 here is you.
And now comes the weaseling. It didn't "sound like it." You did say exaclty that, it's reposted again for you above.
I
If it doesn't take 400 amps to power a 48KVA load at 120volts, then please explain how your math adds up. You claim I'm "interchanging" current and power. In fact, I am not and my math adds up. What is the voltage across the load? 120volts What is the current flowing through the 120 volt loads? 400 amps. What is the power?
48KVA. See how it all works out?
Now let's do it your way. 120volts X 200 amps=3D24KVA. Where is the other half of the missing power? I've asked that previously and gotten no answer other than the lame "you're confusing power with current." I've supplied the straightforward math for the simple circuit I drew above, where is yours?
Here's the other simple question I'm waiting for an answer to. I tell the homeowner he can power a max of 400 amps of 120 volt eqpt. He goes out and buys four 12KW heaters. The box on each one says
120volts, 100 amps, 12KW. That is how these loads are labeled, are they not? He plugs two in on one side of the hot, two in on the other side of the hot. He now has 400 amps of 120 volt loads powered.
Following your answer, he instead comes home with only two 12KW heaters and only gets to use half the available service power. Why is he only getting half his load if he listens to you? Doesn't that bother you?
In simple terms, for some strange reason, you want to ignore a current passing through a second load and generating power. You don't count current twice in a circuit in a way that would violate Kirchoff's Law. But you do count it twice if it flows through two seperate loads, powering each of them. That is the only way physics explains the power.
Since you want to drag education into it, I've stated my credentials. I have a BS in Electrical Engineering from the Massachusettes Institute of Technology. I spent 16 years in various capacities, many of them engineering, with Intel. Bud, who also says you are nuts, has an Electrical Engineering degree from the Univ of Minnesota Institute of Technology. And precisely what are your qualifications?
No they are NOT 'out of phase' the two 240 'ends' are the opposite ends of a single phase 240v winding of the distribution transformer! they are often incorrectly referred to as 'phases. but are actually Leg A and leg B. And when on of them is +ve the other leg is -ve with respect to it. The neutral is the centre tap of that distribution transformer winding.
Yeah, that's pretty much what I expected, no fact, no answers to the several simple direct questions that are the core of the issue, just emotion.
Here's just a couple more question for you big boy. What is the total power that a 200 amp 240volt service can deliver to a resistance load of heaters? Everyone else that I've seen post here agrees that it is
48KW. Do you agree?
So, I hook up those four 12Kwatt heaters from my example to my 200 amp service. I place two on each side. I now have a balanced 120volt load, 24KW on each side, the total power is 48KW. With me so far? The voltage on each and every one ofl the loads is 120volts. So, if
400 total of amps is NOT flowing through the LOADS, then how do I get
48KW out of the service? Or is it your position that I can only get
24KW out of the service?
Those are the kinds of simple questions any first year EE student can answer. My math adds up, we have yet to see yours.
Sorry for that comment, I had to go take some insulin.
I ran this buy the engineering staff at work and they agreed with me. Then I realized a few minutes ago that we ARE talking about a residential environment, I deal with industrial installations, mostly testing and installations of UPS's and generators. The point I was trying to make to the OP is that there will never be 400 amps in the box. There will never be 400 amps flowing anywhere.
It appeared to me and the engineering staff that claims were being made that there would be 400 amps of current flowing at 120VAC. This is what I disagreed with. Part of the reason for my argument is that while this MAY be a question a typical home owner could ask I did not view it as such as such, it is also a classical "gotcha question". Usually the question is just tossed out in a classroom for discussion to get people thinking but a few instructors will put it on a test. The guys at work saw it the same way.
I agree that asking if the box will will support 400 1 amp 120 vac loads is a question a home owner may ask and the answer is YES in theory and I have said so. If this was a real homeowner type question the answer would be NO. He would be risking overloading the box.
The only point is that I am making is that there will never be 400 amps of current flowing in the box.The LINE Input will not "see" the load as 400 1 amp 120 VAC loads it will only "see" it as a 200 amp 240 vac load. If you add up all the currents through each individual current paths there will never be more than 200amps. The way I see it
2 120 vac 1 amp loads in series is is going to be one path. There is no node or legitimate sum of nodes where 400 amps is flowing in the box.
A home owner may see it as 400 1 amp 120vac loads but that is not the reality of what is happening in the panel. I think our disagreement is merely a matter of perception of the problem and a matter of perception of each others answers. We both know what we are talking about.
As far as my education, I eventually got my Electronic Engineering degree at University of Miami after attending 3 different universities spread out over 8 years while in the USAF. When I got out of the AF in the early 80s I discovered there wasnt much call for an electronic engineer.The jobs that were open had a very short life expectancy, most engineers were being hired for special projects with little hope of being retained after the project was finished. I then went back to Georgia Tech for a little over a year for my electrical degree. Never finished it up, A very good long term job came along and I made the choice to take it. .
i was the poster talking about my neighbor with the griswald christmas light display.
i have sad news to report. jerry my neigbor was a smoker, he died from lung cancer. it was a slow cruel way to go, including a unsucccessful attempt at suicide.
Don't do what? A 200 amp panel will support 240V at 200 amps or 400 amps at 120V.
200 amps. is 200 if is 120 or 240, You can not change Amperage Voltage yes Amperage "NO" for 240 Volt max. is 200 amps./leg Each "leg" of 120 Volt, will give max. 200 amps. assuming that neutral is rated for 400 amps.
Sigh. Do we have to go through this all over again? A service rated at 240V, 200A will support a load of 240V, 200A or a balanced load of 120V, 400A. Yes the current in the service conductors never exceeds 200A, but if you have 200A flowing through one leg through 200A of 120V loads, through another 200A of 120V loads, and then back out the other leg, it's handling 400A of 120V loads.
Sigh. Do we have to go through this all over again? A service rated at 240V, 200A will support a load of 240V, 200A or a balanced load of 120V, 400A. Yes the current in the service conductors never exceeds 200A, but if you have 200A flowing through one leg through 200A of 120V loads, through another 200A of 120V loads, and then back out the other leg, it's handling 400A of 120V loads.
Dear Sir you look at it your way and I will look at it my way. have nice day
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