amprage

[stafelectric@yahoo.com]

What is the total amount of amp's, that can be loaded to a 200 amp lighting
panel per phase? Is this not the right calc 200 divided by 3 for a 3 phase app. 200 divided by 3 =66.6 amps per phase/3 times 66.6=200amps total on the panel board.

 

[Dennis Alwon]

Assuming the lighting panel has all continuous loads then you must load the panel to 80% or 160 amps per phase. If there is no continuous loads then you can load the panel 100% or 200 amps per phase.

 

[infinity]

You can have one 200 amp 3 phase load if the lights are not one for more than 3 continuous hours. If you have all single phase loads you can 200 amps on phase A, 200 amps on Phase B and 200 amps on Phase C. Again this would be for non-continuous loads.

 

[Buck Parrish]

Agreed , 200 is 200 ,
Most any demand factors will come before you size the panel.

 

[iwire]

What is the total amount of amp's, that can be loaded to a 200 amp lighting
panel per phase? Is this not the right calc 200 divided by 3 for a 3 phase app. 200 divided by 3 =66.6 amps per phase/3 times 66.6=200amps total on the panel board.

You really cannot think in terms of 'total amps with three phase', it just does not work that way.

You need to think in watts. (and even this is an over simplification)

A 200 amp 3 phase 120Y/208 panel can at most supply 41,601 watts of lighting.

200 x 208 x 1.73 = 41,601 watts

A 200 amp 3 phase 277Y480 panel can at most supply 166,080 watts of lighting.

200 x 480 x 1.73 = 166,080 watts.

 

[Hameedulla-Ekhlas]

Greeting all,
Dear friend be careful and never divide ampere by three. We can divide only kW or kVA by three equal in each phase A, B,C. When we calculate ampere it is always per phase. Because of the following reason.

Voltage = 380 volt
kVA = 500

I = kVA/(1.732*380) = 759.69 ampere per phase

You know the impedance, resistance and reactance are always per phase so when we find ampere it is only per phase ampere.

Hope it is done.

 

[realolman]

It seems to me it would be hard to say that lights would not be a continuous load, unless it was a very specific, known application.

Greetings Hameedulla-Ekhlas

 

[LarryFine]

As the other's have said, you don't say "amps per phase," even though it's kind of right. You specify the amps, the system voltage, and phase, which tells you the total power capacity, which is what is ultimately important.

When you say you have a 200 amp supply, the amount of power it can deliver depends on the voltage you're supplying it at, and on how many line conductors. 200a 3ph is more power than 200a 1ph at a given voltage.

So, to answer the OP's question literally, a 200a supply can deliver 200 amps on each line, or 200a total. (Continuous loads are limited to 80% of that.) Of course, your supply and load voltage ratings must be compatible.

 

[stars13bars2]

It seems to me it would be hard to say that lights would not be a continuous load, unless it was a very specific, known application.

It's not that hard to tell. Commercial = continuous and Residential = not continuous.

 

[skeshesh]

It's not that hard to tell. Commercial = continuous and Residential = not continuous.

Rule of thumb maybe, but not necessarily true. I don't know many people who dont have lights on for much longer than 3 hours a night in a residence.

On the "amp per phase" issue, follow the advice of others in thinking about power rather than current in this case. Understanding three phase power is not extremely complicated, but mastering it could be. I'm not saying you absolutely need a college education to do so, but make sure your an avid reader if you want to get both your grips around really understanding whats going on in those pesky wires.

 

[Hameedulla-Ekhlas]

Dear LarryFine,


Hope you are fine and good and per your statement " 200a 3ph is more power than 200a 1ph at a given voltage. " It means 200Amp 3ph differs from 200Amp 1ph


For three phase power we use line to line voltage
For one phase power we use line to neutral voltage

For three phase we first divide only kVA by three to three Bus bar, A, B, C

we know Apparant Power (S) = VI; it means one phase; for three phase
S(three phase) = 3S(single phase)

It also means that when we say three phase it means Power is three times of Single phase not ampere and also we never can say at a given voltage because we know line to line voltage is for three phase and line to neutral is for single phase.

You know that:

Single phase voltage means line to neutral voltage
Three phase voltage means line to line voltage



S = 1.732 V * I --------(i)

V( line to line voltage )
v ( three phase ) = 380 volt
v ( line to neutral ) = 220 volt

V( line to line ) = 1.732 * V ( line to neutral.

As u have mentioned 200 3ph ampere and 200 1ph ampere are different

Now in equation (i) if you put 200 3ph or you replace the line voltage to neutral voltage and put same 200 1ph ampere the result are same but only there is a voltage difference not Ampere.




Hope it is done.

 

[Besoeker]

As the other's have said, you don't say "amps per phase," even though it's kind of right. You specify the amps, the system voltage, and phase, which tells you the total power capacity, which is what is ultimately important.

When you say you have a 200 amp supply, the amount of power it can deliver depends on the voltage you're supplying it at, and on how many line conductors. 200a 3ph is more power than 200a 1ph at a given voltage.

So, to answer the OP's question literally, a 200a supply can deliver 200 amps on each line, or 200a total. (Continuous loads are limited to 80% of that.) Of course, your supply and load voltage ratings must be compatible.

If it's a 200A supply, then surely it is a 200A supply regardless of voltage?

 

[realolman]

If it's a 200A supply, then surely it is a 200A supply regardless of voltage?

Yeah.. I don't understand the desire to make the distinction.

Each load is going to have a known current and voltage. You're going to have to divvy them up among the breakers in the panel accordingly.... and ultimately somebody's gonna read the current on each phase with a clamp on ampmeter

I can understand doing so when you're in the design stage with a specific wattage per sq. foot, but I don't see how thinking of it in terms of current instead of wattage at any point is going to cause you any big problem.

 

[LarryFine]

If it's a 200A supply, then surely it is a 200A supply regardless of voltage?

Yes, but I was trying to explain that a 3ph 240v supply can deliver more power than a 1ph 240v supply. I didn't realize we were talking to an engineer.

Many newbies ask something to the effect of: "if it's not 200 amps per phase, why do we bother with more phases?"

 

[Besoeker]

Yes, but I was trying to explain that a 3ph 240v supply can deliver more power than a 1ph 240v supply. I didn't realize we were talking to an engineer.

My apologies.
I shouldn't have intruded.

 

[iwire]

It's not that hard to tell. Commercial = continuous and Residential = not continuous.

I hardly think so.

 

[Hameedulla-Ekhlas]

Dear LarryFine,
Could you please give me a little more explaination on the below line

"if it's not 200 amps per phase, why do we bother with more phases?"

 

[LarryFine]

Dear LarryFine,
Could you please give me a little more explaination on the below line

"if it's not 200 amps per phase, why do we bother with more phases?"

I'll try.

Often, we get questions like this from people who don't understand that a 200a supply, for example, is capable of delivering up to 200a on each line conductor, and that that's also a "total" of 200a.

I'm attempting to make the point that we can deliver more power (in the volt-amp sense) by using a 3ph supply instead of 1ph, by using a higher system voltage, and/or both, of course.

The reason 200a "per phase" is only 200a "total" is because we have more than one line capable of delivering that 200a, so there is more than, say, (200a x 120v) 24kva available.

Look at the OP's question again, and then think about my response. If he believed that a 3ph 200a supply could only deliver 66.6a per phase, he'd think that a 1ph 200a supply could deliver 100a per phase.

My point is that using a 3ph supply can deliver more power than using a 1ph supply of the same voltage. Or, despite that 200a "per phase" is only 200a in total, it's still more power than 200a on just one line.

 

[Hameedulla-Ekhlas]

Yes, dear friend I am completely agree with you at this point