Load capacity of 200-amp panel (2024 Update)

[trader4]

I'm not counting electrons twice. Neither is Bud. I take 200 amps worth of 120Volt eqpt and plug it into outlets that are driven off of one hot leg of the 240Volt 200 amp service. I take 200 amps worth of 120volt eqpt and plug it into outlets that are driven off the second hot leg. I am now supporting 400 amps of 120volt loads. It doesn't get any more basic than that. I agree the current is flowing in series and is actually a 240Volt total load and the service is running 200 amps. That is what I have been saying all along when others were saying that you have conductors in parallel, a second conductor carrying more current, etc. But from any reasonable perspective, if I can plug 400 amps worth of 120volt eqpt into the house, then I am in fact driving those loads.

If the homeowner asked you how many amps worth of 120Volt eqpt is the max that the 200 amp service can support, what would your answer be?

[trader4]

Thanks for the kind words Smitty. :)

[trader4]

e quoted text -

By the way, are you the same Jimmie that posted this a while back?

"Assume you are using one leg at 200 amps, that is all the breaker will handle that is 120 volts X 200 amps or 24,000 watts. If you again max out the breaker with 200 amps flowing on both sides that is

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 "

So, now how come when I say the max 120v load that a 200 amp service can supply is 400 amps and then if and only if the load is perfectly balanced, you say NO?

If the homeowner asked you how many amps worth of 120Volt eqpt is the max that the 200 amp service can support, what would your answer be?-

[JIMMIE]

unting

that's 200

e quoted text -

200 AMPS, 200 amps x 240 volts also equals 48000 watts. I suggest you post this to one of the engineering groups. This is a classic question that has been in electical course for years. Ive been thru three such courses in the last 22 years and havent missed the question yet. One course was for power distribution, one was for HVAC and the other was for power generation.

And yes you are counting electrons twice. And your perspective is wrong because the loads are not across 120, there return path is not through the neutral. You have 2 120vac loads connected in series across 240 vac.

Jimmie

[Steve N.]

This thread will go for ever with no satisfying conclusion because of the talk about AMPS instead of Volt Amps or Watts.

[JIMMIE]

You can have 1000 watts with 1 volt and 1000 amps or you can have 1000 watts at 1000 volts and 1 amp. If you follow your logic the power distrubution boxes would be the same.

Jimmie

[AZ Nomad]

Panel capacity isn't measured in VA or watts. If the connections in a panel have enough resistance to cause significant power dissipation then you will very very quickly have burned out connections.

A panel can easily carry enough current for a 10KW load, but if there is so much as 0.05KW of power dissipation inside a connection in the panel, you'll quickly have a burned out connection.

[JIMMIE]

Where have you ever seen a panel rated in VA or WATTS?

Jimmie

[trader4]

ide quoted text -

Wrong.

And I have a degree in electrical engineering from MIT and I say you are nuts. The homeowner brings home twenty 20 amp 120 volt heaters. He connects half of them to outlets on one side of the service. He connects half of them to outlets on the other side of the service. He now is unquestionably supporting 400 amps of

120volt load. It doesnt' get any simpler than that. In fact, I think everyone in the entire thread except you would agree with the above. Sure it is because it works as a series circuit and appears at the service point as a 240volt, 200 amp load. Everyone knows that. But as far as the loads go, you do have 400 amps going through them, 120V * 400a =3D 48KVA of power

Accoridng to your answer above, what would the homeowner do? If he listened to your answer, the homeowner could only buy and connect ten of those 20 amp heaters, because he can only support 200 amps at

120volts.

And aren't you the same Jimmie that posted this back in the beginning of the thread?

"Assume you are using one leg at 200 amps, that is all the breaker will handle that is 120 volts X 200 amps or 24,000 watts. If you again max out the breaker with 200 amps flowing on both sides that is

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 "

Yet, now you say it aint' so.

The homeowner can bring home 400 amps worth of 120volt eqpt and plug it in and it works. Any place in the universe, that means the service is supporting 400 amps of 120volt load.

In fact, that is exactly what you said in your own post, which I showed above.

[trader4]

Yes, it sure is. Even more so when Jimmie is on both sides, essentially arguing against his own post.

The only issue I have with Doug is that he refuses to acknowledge that there is only a max 200 amp current flowing in the service cable. I freely answered ALL his questions, yet for some reason he won't give a straight answer to the simple question of how many amps max can ever be flowing in the service cable. And in trying to evade the question he dragged in voltage and power, which are seperate from the question of how many amps max are ever flowing in the service cable.

[bud--]

Yup.

Have fun with JIMMIE. Surprising how a simple question is so controversial.

I don't see the series argument as particularly interesting, but maybe again POV. In a slight tangent, if you have a 200A 3-phase 120/208V Y panel and load A-phase at 200A 120V, B-phase at 200A 120V, and C-phase at zero, you will have 400A connected 120V load and a 200A neutral current.

The same is true with a single phase panel fed by 2 legs of a 3-phase supply. I believe you can get that in large apartment complexes that have a 3-phase service.

And I hesitate to say it again, but I understood Doug to have said the same thing as in the previous 2 posts. I think he used "parallel" once, which I understood to mean "combined" (200+200), as applied to the 120V loads. I don't remember he ever other wise implied there was 400A in the neutral.

[bud--]

What a coincidence. I have a degree in electrical engineering from the (university of) Minnesota Institute of Technology too.

What a coincidence. I think he is nuts too.

Hey - that's not fair.

Why would you use such an underhanded tactic to ruin a perfectly good argument?

-- bud--

[JIMMIE]

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Doesnt matter if there is no current flow in the neutral, Quit trying to reason what you dont understand and build a mock up circuit if this really concerns you that much. I am growing very bored of talking to people who are more interested in defending their argument than actually trying to learn something. Any decent text that explains Kerchov's(sp?) Law as applied to AC circuits will give you the answer.

Jimmie

[Doug Miller]

[major snippage]

ROTFLMAO! This is *exactly* what I've been saying in this thread for the last week -- and you've been telling me I was wrong.

[Doug Miller]

In fact, I explicitly corrected at least one person who said there was. In at least two posts, I stated clearly that the neutral carries only the unbalanced current, and if the loads in the two legs are exactly balanced the current in the neutral is zero.

[Doug Miller]

"But as far as the loads go, you do have 400 amps going through them, 120V * 400a = 48KVA of power".

That's a quote from one of *your* posts.

Apparently, it *is* possible to have a current > 200 amps -- as long as it's you saying so, not me.

[JIMMIE]

Nope I made a mistake, I meant to point out that the OP could get the power he wanted but not at 400 amps. What I said was wrong. Im still trying to figure out what led me so say what I did . There are lot of numbers you can multiply times each other and get 48K you might as well pick any from the group if you use your logic. The panel is rated

200 amps @ 240 volts, not 400 amps@ 120 volts. Power has nothing to do with it. I could use the box to distribute 24VAC and it would still only be able to handle 200 amps. According to your logic it should handle 2000 amps, Hey that's 48KW said very much tongue in cheek..

Jimmie

[trader4]

You do not have a physical current of more than 200 amps flowing in the service cable. THAT is what I have been saying all along. That is very different from supporting a LOAD of 400 amps worth of 120volt equipment. And once again, let me point out that I have courteously answered every one of your questions, yet you will not answer the simple direct question I have asked you repeatedly. I even asked it again above, yet you choose to hide from it:

How many amps max are actually flowing in the service cable?

Answer:200

Do you agree, yes or no?

[trader4]

So expalin us the physics whereby I can get 48KVA at 120 volts without a current of 400 amps.

No, when you said a 200 amp service can support 400 amps worth of

120volt load you were correct. It's now that you;'ve reversed yourself that you are wrong.

That is correct because that is EXACTLY what you can do. Which is why I gave other examples. Let's take a heater consisting of a a .

3ohm resistance. The box says it's 60volts, 200 amps, 12Kwatts or KVA. Agree?

I take TWO of those and place them is series and connect them to one side of the service. I take another two and place them in series on the other side of the service. I now have 4 loads. Each one is running at 200 amps and 60volts. Agree?

I'm now supporting FOUR 200 amp, 60 volt loads. Across the service it looks like one 240volt, 200 amp load. Capishe?

No, according to my correct logic and math the current in the service is still 200 amps which is what the panel is rated for. However if I use voltage division, I can divide up that VOLTAGE across various loads any way I want. I gave you a clear example of that above.

Since you say otherwise, please to explain how a 240volt, 200 amp

48KVA service becomes only capable of supporting 200 amps of 120volt load. You even said if the homeowner asked you:

What is the maximum 120 volt load that I can hook up to this 200 amp,

240volt servce?

Your answer would be 200 amps.

My answer and I think virtually everyone else in this thread's answer is 400 amps, because in fact that is how much 120 volt load can be hooked up. With your answer, the homeowner goes out, looks at the rating labels on all the equipment and is limited to 200 amps,

120volt, 24KVA. Where is the rest of the poor guy's power?

[JayB]

Thanks all. I thought I replied back sooner but I don't see my reply anywhere.

I did get the answer to my questi> This came up elsewhere and I am just curious about what the answer is. >