200 amps?

[lendog]

I have a question when you have a single phase 200 amp panel is each phase on the panel good for 100 amps and thats how you get 200, or is each phase good for 200 amps?

 

[iwire]

I have a question when you have a single phase 200 amp panel is each phase on the panel good for 100 amps and thats how you get 200, or is each phase good for 200 amps?

Each phase is capable of 200 amps.

But amps (current) is a poor way to describe how much power a panel is capable of providing.

If you are really interested in how much power a panel can provide you should be thinking in terms of watts or actually Kilowatts (KW).

I will use a 200 amp panel as an example.

A 200 amp 120/240 single phase panel in a home is capable of providing 48,000 watts (48 KW) of power.

A 200 amp 208Y/120 three phase panel is capable of providing 71,000 watts (71 KW) of power.

A 200 amp 480Y/277 three phase panel is capable of providing 166,000 watts (166 KW) of power.

As you can see three 200 amp panels can have greatly different power capabilities.

 

[Dexie123]

Each phase is capable of 200 amps.

But amps (current) is a poor way to describe how much power a panel is capable of providing.

If you are really interested in how much power a panel can provide you should be thinking in terms of watts or actually Kilowatts (KW).

I will use a 200 amp panel as an example.

A 200 amp 120/240 single phase panel in a home is capable of providing 48,000 watts (48 KW) of power.

A 200 amp 208Y/120 three phase panel is capable of providing 71,000 watts (71 KW) of power.

A 200 amp 480Y/277 three phase panel is capable of providing 166,000 watts (166 KW) of power.

As you can see three 200 amp panels can have greatly different power capabilities.

I'm with you Iwire but if you are saying "each phase" is capable then w'hy wouldn't you multiply, in say your first example, 240v * 400 to give you 96kw as apposed to 240v * 200 giving you 48kw?

 

[jaylectricity]

I'm with you Iwire but if you are saying "each phase" is capable then w'hy wouldn't you multiply, in say your first example, 240v * 400 to give you 96kw as apposed to 240v * 200 giving you 48kw?

There are three legs in the last panel...there are only two in the first panel. Plus I'm sure the fact that one leg is different than the rest comes into play. Someone can probably explain better but at least you get a relatively quick answer for now.

 

[jetlag]

each phase only 120v

each phase only 120v

I'm with you Iwire but if you are saying "each phase" is capable then w'hy wouldn't you multiply, in say your first example, 240v * 400 to give you 96kw as apposed to 240v * 200 giving you 48kw?

1 phase 120 v x 200 a = 24000 + 120v x 200 a = 24000 = total 48 kva
3 phase 120v x 200 a = 24000 x 3 ph = tota 72 kva

3 phase 440 277 = 277v x 200a = 55400 x3 =total 166 kva

 

[Dexie123]

Of course, how silly of me

 

[busman]

Is there really an "electrician" who doesn't know how many amps/phase in a residential 200A service. The OCPD should tell you that. Sounds like Harry-Home-Owner?

Sorry - just grumpy tonight.

Mark

 

[stickboy1375]

I don't know, but at least the OP asked....

 

[jaylectricity]

Is there really an "electrician" who doesn't know how many amps/phase in a residential 200A service. The OCPD should tell you that. Sounds like Harry-Home-Owner?

Sorry - just grumpy tonight.

Mark

What good would it do Harry-Home-Owner to know the answer to this question? Sounds like a guy just getting into the trade asking a question that he didn't feel comfortable asking his real life peers.

Take a chill pill, tonight will be over soon enough and then it will be MONDAY!

 

[cjnickjr]

Quote:
Originally Posted by Dexie123
I'm with you Iwire but if you are saying "each phase" is capable then w'hy wouldn't you multiply, in say your first example, 240v * 400 to give you 96kw as apposed to 240v * 200 giving you 48kw?

1 phase 120 v x 200 a = 24000 + 120v x 200 a = 24000 = total 48 kva
3 phase 120v x 200 a = 24000 x 3 ph = tota 72 kva

3 phase 440 277 = 277v x 200a = 55400 x3 =total 166 kva
Let me take a shot at this.
First, each phase is capable of 200A whether the current is line to line or line to neutral. You would'nt put a 200A load from A to Neutral and an additional 200A load from B to Neutal. Thats 400 amps, alot of fire and smoke.
Second, what would you calculate for a 3 phase Delta 240/120V panel?
(3phase 120V x 200A = 24000 x 3ph = total 72kva?) Although your other calculations came out as correct the formula used was not. The correct calculation in this case is 240V x 200A x 1.73 = 83KVA. Compare this to 208V x 200A x 1.73 = 72KVA

 

[LarryFine]

First, each phase is capable of 200A whether the current is line to line or line to neutral. You would'nt put a 200A load from A to Neutral and an additional 200A load from B to Neutal. Thats 400 amps, alot of fire and smoke.

No, you're wrong. 200a A to N is 200a @ 120v, or 24Kva; 200a B to N is 200a @ 120v, or 24Kva. Add the two together and you get 200a A to B, which is 48Kva.

Or, you can do 200a A to B, which is 48Kva. You can do one or the other, or a mix, such as 100a A to N and 100a B to N and 100a A to B all at the same time.

You can load A to N at 200a, and then as you add load to B to N, each amp added is an amp less on the neutral, until you have 200a on A and B, and zero amps on the neutral.

 

[Twoskinsoneman]

No, you're wrong. 200a A to N is 200a @ 120v, or 24Kva; 200a B to N is 200a @ 120v, or 24Kva. Add the two together and you get 200a A to B, which is 48Kva.

Or, you can do 200a A to B, which is 48Kva. You can do one or the other, or a mix, such as 100a A to N and 100a B to N and 100a A to B all at the same time.

You can load A to N at 200a, and then as you add load to B to N, each amp added is an amp less on the neutral, until you have 200a on A and B, and zero amps on the neutral.

IMO This explanation is exactly right.

 

[lendog]

thanks for the help, sorry

 

[iwire]

Let me take a shot at this.
First, each phase is capable of 200A whether the current is line to line or line to neutral.

Yes, that is true but line to line vs line to neutral does make a difference when figuring power in watts or KW.

You would'nt put a 200A load from A to Neutral and an additional 200A load from B to Neutal. Thats 400 amps, alot of fire and smoke.

Yes you could do exactly that and there would be no fire, no smoke, no code violation.

Lets say do that, I have a 120/240 200 amp single phase panel. I connect 200 amps of 120 volt loads 'A to Neutral' and another 200 amps of 120 loads 'B to Neutral'.

What do you expect the load on the neutral to be?

400 Amps?

200 Amps?

0 Amps?

With both legs A and B loaded simultaneously at 200 amps the load on the neutral will be 0 amps

Second, what would you calculate for a 3 phase Delta 240/120V panel?
(3phase 120V x 200A = 24000 x 3ph = total 72kva?) Although your other calculations came out as correct the formula used was not. The correct calculation in this case is 240V x 200A x 1.73 = 83KVA. Compare this to 208V x 200A x 1.73 = 72KVA

Not following you at all here and why bring in another type of system?

I am also curious how you got 3 legs of 120 volt from a delta panel?

As far as which formula is correct there are many different ways of arriving at the correct answer, just because it is not the formula you use does not make it incorrect.



I also agree with Larry's post here..

No, you're wrong. 200a A to N is 200a @ 120v, or 24Kva; 200a B to N is 200a @ 120v, or 24Kva. Add the two together and you get 200a A to B, which is 48Kva.

Or, you can do 200a A to B, which is 48Kva. You can do one or the other, or a mix, such as 100a A to N and 100a B to N and 100a A to B all at the same time.

You can load A to N at 200a, and then as you add load to B to N, each amp added is an amp less on the neutral, until you have 200a on A and B, and zero amps on the neutral

 

[busman]

What good would it do Harry-Home-Owner to know the answer to this question? Sounds like a guy just getting into the trade asking a question that he didn't feel comfortable asking his real life peers.

Take a chill pill, tonight will be over soon enough and then it will be MONDAY!

OK - now it's Monday morning. Sorry - at least I knew enough to apologize yesterday as soon as I typed it. It just seemed like a fairly basic question from a new member on the first post with a profile that says "electrician".

I was grumpy because I spent most of the weekend doing the low-belly-crawl thru bad yellow insulation in a 120 degree attic to clean up behind a HHO who didn't use boxes (just attach light, recpt, etc. to plaster); didn't use wirenuts (just make two hooks and tape with duct tape); didn't know they made 3-wire cables so just taped single conductors to 2-wire cables. Needless to say, this eventually started a fire. Was just having a low tolerance day. I would post the photos, if I could ever figure out how.

Mark

 

[jaylectricity]

OK - now it's Monday morning. Sorry - at least I knew enough to apologize yesterday as soon as I typed it. It just seemed like a fairly basic question from a new member on the first post with a profile that says "electrician".

I was grumpy because I spent most of the weekend doing the low-belly-crawl thru bad yellow insulation in a 120 degree attic to clean up behind a HHO who didn't use boxes (just attach light, recpt, etc. to plaster); didn't use wirenuts (just make two hooks and tape with duct tape); didn't know they made 3-wire cables so just taped single conductors to 2-wire cables. Needless to say, this eventually started a fire. Was just having a low tolerance day. I would post the photos, if I could ever figure out how.

Mark

Ick, I hear ya man. I was just joshin you so don't get me wrong or anything.

As far as pictures go if they are on the internet all you have to do is click the little box that looks like a mountain range and copy and paste the address of the pic in between the two sets of brackets.

Have a good day, I'll check back tonight to see if you figured out the picture thing.

 

[jetlag]

maybe this will help

maybe this will help

You can multiple 120v (line to neutral) times the amps for each leg on a 208 3 phase system and add all 3 together for total VA . It will give the same answer as multiply 208 times amps times 1.73 Try it. for 200a is 72 kva

but on 3 ph delta there is a high leg 173 v . so there are two legs 120 v times the amps and one leg 173 v times the amps . add all together is the same as 240 times amps times 1.73 for 200 a is 83kva

 

[LarryFine]

I would post the photos, if I could ever figure out how.

Mark, if you like, email me the photos and I'll put them on my server and post links.

By the way, I hope (a) that wasn't your house and (b) you charged a LOT!

 

[busman]

OK - here goes:

Moderator Edit: You pictures posted fine but at 2500 x 2000 are way to large for posting on the forum so I had to remove them. Please edit the photos so that no dimension is more than 600 and set the dpi at around 70. Once they are edited feel free to repost them. With them so large they are difficult to see and our dial up users will be waiting ages for them to finish down loading.

Thanks Bob

 

[busman]

Bob,

Thanks for the help. Still learning. I'll try to re-post tonight. Anybody have tips on an application to reduce the resolution?

Mark