3-pole circuit breaker voltage rating on single phase

Consider a 3-pole circuit breaker with the pole sections side by side
so that pole 1 and pole 3 have pole 2 in the middle. This is a very
typical circuit breaker design for molded case breakers from companies
like Cutler-Hammer and Square-D. These typically have a voltage rating
giving a single number, and suitable for that voltage line to line and
relative to ground. For example a 480 volt rating would allow use in
a 480Y/277 volt WYE system, as well as a 480 volt corner grounded delta
system. These breakers typically have ampere ratings as high as 1200.
This would be in contrast to typical miniature branch breakers that have
a dual voltage rating, one for line to ground and the other for line to
line, such as 120/240 or 480/277.
Here's what I want to learn more about. Presumably these breakers
might not have any greater line to line voltage rating than line to
ground because they may be constructed with no extra insulation levels
between the poles. The insulation between poles could very well be
just the same as the insulation to the outside. This would contrast
with placing two or three single pole breakers side by side where you
would have double the insulation between poles, and some amount of
greater voltage capability between them (perhaps).
What I want to focus on in a 3-pole molded case breaker is the voltage
"endurance" capability (I'm avoiding the term "rating" here so as not
to be confused with formal standard ratings such as UL, or manufacturer
specifications that could incur legal liability) between the FAR poles,
e.g. between pole 1 and pole 3 of a three pole breaker. Is there any
reason there could not be an even higher voltage "endurance" between
these far poles, as long as the middle pole in between does not have a
relative voltage any greater than the formal rating?
Consider a 480 volt 3 pole breaker, such as Square-D model FAL34100
or others like it. It can be used on a 480 volt delta three phase
power system. But what about a single phase system where there are
two poles at 180 degrees phasing, with 480 volts relative to ground
on each, e.g. a 480-0-480 system, with the middle pole connected to
the grounded neutral wire of this system? Between pole 1 and pole 2
there would be 480 volts. Between pole 2 and pole 3 there would be
480 volts. But between pole 1 and pole 3 there would be 960 volts!
But these poles are well separated by the middle pole.
If that's a little high for you, then try a lower voltage breaker such
as the QDL32100 (rated for 240 volts, including 240 delta) being used
on a 240-0-240 single phase system connected as described, where it
would see 480 volts between pole 1 and pole 3.
In what way could a breaker like that NOT have a voltage "endurance"
capability of 960 volts between poles 1 and 3 when the middle pole is
connected to the grounded conductor that has no more than 480 volts
relative to either phase?
Please note that I am NOT asking about formal specification or rating.
I'm NOT asking of such a connection would be in compliance with any
electrical code, or if such a connection would be consistent with the
purpose it is safety listed for. I am asking about the physics of the
design, and any aspect of electricity that would make it not possible
for a breaker to generally be capable of doing this.
such systems are in common use.
Reply to
phil-news-nospam
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Reply to
operator jay
|> Consider a 3-pole circuit breaker with the pole sections side by side | | ... | |> -------------------------------------------------------------------------- | --- |> | Phil Howard KA9WGN |
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| |> -------------------------------------------------------------------------- | --- | | Not knowing about circuit breaker construction, I would consider that there | could be something conductive (or even 'less insulative') in the breaker | construction which would 'bridge' some of the separation between the 1st and | 3rd poles, without effecting the effective insulation between pole 1 and | pole 2 or between pole 2 and pole 3. Imagine there were a metal pin (about | the width of pole 2) that the breaker handle hinged on. Maybe a voltage | difference of 900V between pole 1 and pole 3 would be enough to wear down | insulation between 'pole 1 and hinge' and between 'hinge and pole 3'. For | example.
That is very plausible. But I don't care to spend $500 or more for one of these to bust it open to see what's in there (I'm sure someone will suggest that at some point).
Reply to
phil-news-nospam
|> ------------------------------------------------------------------------- -
|> ------------------------------------------------------------------------- - > | --- > | > | Not knowing about circuit breaker construction, I would consider that there > | could be something conductive (or even 'less insulative') in the breaker > | construction which would 'bridge' some of the separation between the 1st and > | 3rd poles, without effecting the effective insulation between pole 1 and > | pole 2 or between pole 2 and pole 3. Imagine there were a metal pin (about > | the width of pole 2) that the breaker handle hinged on. Maybe a voltage > | difference of 900V between pole 1 and pole 3 would be enough to wear down > | insulation between 'pole 1 and hinge' and between 'hinge and pole 3'. For > | example. > > That is very plausible. But I don't care to spend $500 or more for one of > these to bust it open to see what's in there (I'm sure someone will suggest > that at some point). > > -- > --------------------------------------------------------------------------
Reply to
operator jay
| I never thought about destructive testing. If you use ebay and the like, | maybe you could find something for $15 since it doesn't actually have to | work. Or if you happen to know some electrical contractors, maybe they | could bring you a 200A breaker they pulled out of a reno that they were | going to throw away.
The test might not prove anything. It might stand up fine to the extra voltage in the test, but in reality have a limited lifetime due to it.
Maybe it might be better if someone who designs such breakers were to consider what it would take to upgrade the design to handle twice the voltage between A and C.
Reply to
phil-news-nospam
You might want to look at the DC rating of these breakers. Some are rated by Square D to handle over 500VDC in UPS service, in which the DC system is ungrounded. Typically, the positive DC lead is broken through two adjacent breaker poles in series while the negative DC lead is broken through the third breaker pole. Merlin Gerin has an IEC rating of 1000VDC on their Masterpact brekaer. Regards, Chris Johnston
Reply to
Chris Johnston
Use for intended purpose only. Maybe you have read that somewhere in the NEC.
Consider a 3-pole circuit breaker with the pole sections side by side so that pole 1 and pole 3 have pole 2 in the middle. This is a very typical circuit breaker design for molded case breakers from companies like Cutler-Hammer and Square-D. These typically have a voltage rating giving a single number, and suitable for that voltage line to line and relative to ground. For example a 480 volt rating would allow use in a 480Y/277 volt WYE system, as well as a 480 volt corner grounded delta system. These breakers typically have ampere ratings as high as 1200. This would be in contrast to typical miniature branch breakers that have a dual voltage rating, one for line to ground and the other for line to line, such as 120/240 or 480/277.
Here's what I want to learn more about. Presumably these breakers might not have any greater line to line voltage rating than line to ground because they may be constructed with no extra insulation levels between the poles. The insulation between poles could very well be just the same as the insulation to the outside. This would contrast with placing two or three single pole breakers side by side where you would have double the insulation between poles, and some amount of greater voltage capability between them (perhaps).
What I want to focus on in a 3-pole molded case breaker is the voltage "endurance" capability (I'm avoiding the term "rating" here so as not to be confused with formal standard ratings such as UL, or manufacturer specifications that could incur legal liability) between the FAR poles, e.g. between pole 1 and pole 3 of a three pole breaker. Is there any reason there could not be an even higher voltage "endurance" between these far poles, as long as the middle pole in between does not have a relative voltage any greater than the formal rating?
Consider a 480 volt 3 pole breaker, such as Square-D model FAL34100 or others like it. It can be used on a 480 volt delta three phase power system. But what about a single phase system where there are two poles at 180 degrees phasing, with 480 volts relative to ground on each, e.g. a 480-0-480 system, with the middle pole connected to the grounded neutral wire of this system? Between pole 1 and pole 2 there would be 480 volts. Between pole 2 and pole 3 there would be 480 volts. But between pole 1 and pole 3 there would be 960 volts! But these poles are well separated by the middle pole.
If that's a little high for you, then try a lower voltage breaker such as the QDL32100 (rated for 240 volts, including 240 delta) being used on a 240-0-240 single phase system connected as described, where it would see 480 volts between pole 1 and pole 3.
In what way could a breaker like that NOT have a voltage "endurance" capability of 960 volts between poles 1 and 3 when the middle pole is connected to the grounded conductor that has no more than 480 volts relative to either phase?
Please note that I am NOT asking about formal specification or rating. I'm NOT asking of such a connection would be in compliance with any electrical code, or if such a connection would be consistent with the purpose it is safety listed for. I am asking about the physics of the design, and any aspect of electricity that would make it not possible for a breaker to generally be capable of doing this. such systems are in common use.
-- ----------------------------------------------------------------------------- | Phil Howard KA9WGN |
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Reply to
Brian
| Use for intended purpose only. Maybe you have read that somewhere in the NEC.
Ah, another person who hits reply without reading the posting. If you did read it, you could see I am not asking about what is legal or compliant. If you did read it, you would see that I am asking about theory. But just for you I'll try it with a different wording. Maybe being shorter you might read it.
Consider that your job is to design circuit breakers. A new product is to be offered in the form of a breaker that can handle a 240/480 volt single phase system, where both lines are 240 volts to ground. The product manager suggests taking an existing 3-phase 240 volt delta breaker that is rated for up to 240 volts, and making changes so that the two phases can be connected though pole A and pole C, with pole B being connected to neutral (and optionally even switching it). So how much work would be required to take a _typical_ breaker of that type (can handle 240 volt corner grounded delta) and make it handle 240/480 volt single phase.
Now, if you are a real designer of circuit breakers, you might be able to answer the question (aside from any trade secret issues that might exist). OTOH, if you don't know enough about inside these breakers to answer it, then there isn't anything you could contribute to answering this. But maybe you know enough about them to speculate.
I suspect the possibility is that the breaker would handle it with no changes needed, and this is simply has never been tested for that voltage because of the lack of market, and lack of a listing program at UL for that voltage level.
Reply to
phil-news-nospam
Breaker on the neutral?!? WTF! Since when does anyone need to have surge protection on the neutral? Do you remember Ohms Law?
| Use for intended purpose only. Maybe you have read that somewhere in the NEC.
Ah, another person who hits reply without reading the posting. If you did read it, you could see I am not asking about what is legal or compliant. If you did read it, you would see that I am asking about theory. But just for you I'll try it with a different wording. Maybe being shorter you might read it.
Consider that your job is to design circuit breakers. A new product is to be offered in the form of a breaker that can handle a 240/480 volt single phase system, where both lines are 240 volts to ground. The product manager suggests taking an existing 3-phase 240 volt delta breaker that is rated for up to 240 volts, and making changes so that the two phases can be connected though pole A and pole C, with pole B being connected to neutral (and optionally even switching it). So how much work would be required to take a _typical_ breaker of that type (can handle 240 volt corner grounded delta) and make it handle 240/480 volt single phase.
Now, if you are a real designer of circuit breakers, you might be able to answer the question (aside from any trade secret issues that might exist). OTOH, if you don't know enough about inside these breakers to answer it, then there isn't anything you could contribute to answering this. But maybe you know enough about them to speculate.
I suspect the possibility is that the breaker would handle it with no changes needed, and this is simply has never been tested for that voltage because of the lack of market, and lack of a listing program at UL for that voltage level.
-- ----------------------------------------------------------------------------- | Phil Howard KA9WGN |
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Reply to
Brian
| Breaker on the neutral?!? WTF! Since when does anyone need to have surge protection on the | neutral? Do you remember Ohms Law?
I know Ohms law. How do _you_ think Ohms law applies in this case?
It is done in many places for good reason. It can be done in others for any reason. As long as the breaker or disconnect can ensure that the neutral never opens before all others are open, and never closes after any others are closed, it can be done.
However, in the scenario I describe, it is not necessary to actually break the neutral connection. Instead, you have a solid neutral bar as you would with a 2-pole breaker, but with the 3-pole breaker you connect both in and out lugs of the middle (B) pole to the neutral bar, along with the supply and load wires (4 total, and maybe even the ground bond if this is the service entrance).
The idea is to hold the mechanism of the middle pole at a reference voltage, rather than let it float between the 2 hot poles.
| | | | Use for intended purpose only. Maybe you have read that somewhere in the NEC. | | Ah, another person who hits reply without reading the posting. | If you did read it, you could see I am not asking about what is | legal or compliant. If you did read it, you would see that I | am asking about theory. But just for you I'll try it with a | different wording. Maybe being shorter you might read it. | | Consider that your job is to design circuit breakers. A new | product is to be offered in the form of a breaker that can | handle a 240/480 volt single phase system, where both lines | are 240 volts to ground. The product manager suggests taking | an existing 3-phase 240 volt delta breaker that is rated for | up to 240 volts, and making changes so that the two phases | can be connected though pole A and pole C, with pole B being | connected to neutral (and optionally even switching it). So | how much work would be required to take a _typical_ breaker | of that type (can handle 240 volt corner grounded delta) and | make it handle 240/480 volt single phase. | | Now, if you are a real designer of circuit breakers, you might | be able to answer the question (aside from any trade secret issues | that might exist). OTOH, if you don't know enough about inside | these breakers to answer it, then there isn't anything you could | contribute to answering this. But maybe you know enough about | them to speculate. | | I suspect the possibility is that the breaker would handle it | with no changes needed, and this is simply has never been tested | for that voltage because of the lack of market, and lack of a | listing program at UL for that voltage level. | | -- | ----------------------------------------------------------------------------- | | Phil Howard KA9WGN |
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| | | (first name) at ipal.net |
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Reply to
phil-news-nospam
with all due repect }:-p this post is rediculous.
use the proper breaker for the proper circuit type.
disconnecting the common or neutral side of the circuit is not all that safe in any circumstance, seeming the load side may have capacitive loads that will need a discharge path in the event of a :-prt malfucntion.
=AEoy
Reply to
Roy Q.T.
| with all due repect }:-p | this post is rediculous. | | use the proper breaker for the proper circuit type.
Roy ... even you are misreading what I'm asking. Wow. What does it take to get people to answer the question I actually ask, rather than the one they wish I had asked?
I'm asking about what it is in a circuit breaker that would make a 3-pole breaker not be able to handle twice the voltage between A and C as it can handle between A and B as well as B and C? Or what changes would need to be made to the typical 3-pole breaker to do this?
Here's another way to phrase it. Let's suppose there are two different products, one being a 3-pole breaker suitable for 480 volt delta, and another 3-pole breaker suitable for 480/960 volt single phase under the stipulation that the B-pole be connected to (but not necessarily switch) the neutral conductor (e.g. the neutral can pass around it as well). So with these 2 breakers, what would be different? Or how hard would it be to make one that can meet both requirements in the same unit?
I'm getting the sense that (most) everyone who has responded does not know anything about the design and construction of a circuit breaker (or else cannot divulge anything for NDA reasons).
| disconnecting the common or neutral side of the circuit is not all that | safe in any circumstance, seeming the load side may have capacitive | loads that will need a discharge path in the event of a :-prt | malfucntion.
And what if this load is a 2-wire 240 volt that simply has no neutral?
Sounds like they need a ground path, not a neutral path. There are many reasons to disconnect the neutral. Some are even required by the code, such as certain locations with flammable hazards, as well as transfer switches that are not the service entrance. Others are merely allowed by the code with specific precautions to ensure the neutral is never in an open state when any hot wire is in a closed state.
Reply to
phil-news-nospam
You just described a "disconnect" perfectly. Minus the part about a breaker of course.
| Breaker on the neutral?!? WTF! Since when does anyone need to have surge protection on the | neutral? Do you remember Ohms Law?
I know Ohms law. How do _you_ think Ohms law applies in this case?
It is done in many places for good reason. It can be done in others for any reason. As long as the breaker or disconnect can ensure that the neutral never opens before all others are open, and never closes after any others are closed, it can be done.
However, in the scenario I describe, it is not necessary to actually break the neutral connection. Instead, you have a solid neutral bar as you would with a 2-pole breaker, but with the 3-pole breaker you connect both in and out lugs of the middle (B) pole to the neutral bar, along with the supply and load wires (4 total, and maybe even the ground bond if this is the service entrance).
The idea is to hold the mechanism of the middle pole at a reference voltage, rather than let it float between the 2 hot poles.
| | | | Use for intended purpose only. Maybe you have read that somewhere in the NEC. | | Ah, another person who hits reply without reading the posting. | If you did read it, you could see I am not asking about what is | legal or compliant. If you did read it, you would see that I | am asking about theory. But just for you I'll try it with a | different wording. Maybe being shorter you might read it. | | Consider that your job is to design circuit breakers. A new | product is to be offered in the form of a breaker that can | handle a 240/480 volt single phase system, where both lines | are 240 volts to ground. The product manager suggests taking | an existing 3-phase 240 volt delta breaker that is rated for | up to 240 volts, and making changes so that the two phases | can be connected though pole A and pole C, with pole B being | connected to neutral (and optionally even switching it). So | how much work would be required to take a _typical_ breaker | of that type (can handle 240 volt corner grounded delta) and | make it handle 240/480 volt single phase. | | Now, if you are a real designer of circuit breakers, you might | be able to answer the question (aside from any trade secret issues | that might exist). OTOH, if you don't know enough about inside | these breakers to answer it, then there isn't anything you could | contribute to answering this. But maybe you know enough about | them to speculate. | | I suspect the possibility is that the breaker would handle it | with no changes needed, and this is simply has never been tested | for that voltage because of the lack of market, and lack of a | listing program at UL for that voltage level. | | -- | ----------------------------------------------------------------------------- | | Phil Howard KA9WGN |
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-- ----------------------------------------------------------------------------- | Phil Howard KA9WGN |
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Reply to
Brian
Phil, Phil, Phil :-) & to the OP. check this out: If a 3phase or ganged 3ph cb trips where a 1 phase or single cb doesn't it only tells you one thing, that only one of the phases has surpassed it's in rated load, not the necesarily the other 2, a 3phase ganged circuit breaker will trip all phases when only One Phase is Overcurrent.... It's Ganged it can't do any better,2 Phases of a 3 Phase Circuit protected with Single Rated CB on each Phase will trip only phases or circuits which in fact are overcurrent or shorted.
* Then of course there are magnetic breakers & heat treated breakers }:-O
I still think this is ridiculous};-){simple} =AEoy
Reply to
Roy Q.T.
| Phil, Phil, Phil :-) & to the OP. check this out: If a 3phase or ganged | 3ph cb trips where a 1 phase or single cb doesn't it only tells you one | thing, that only one of the phases has surpassed it's in rated load, not | the necesarily the other 2, a 3phase ganged circuit breaker will trip | all phases when only One Phase is Overcurrent.... It's Ganged it can't | do any better,2 Phases of a 3 Phase Circuit protected with Single Rated | CB on each Phase will trip only phases or circuits which in fact are | overcurrent or shorted.
And hos does this relate to the voltage capability of the breaker?
Or maybe you were thinking I meant single pole when I say single phase? But I'm not. I'm referring to a 3-pole breaker with one handle all ganged together, regardless of which circuit it is on.
Reply to
phil-news-nospam
| You just described a "disconnect" perfectly. Minus the part about a breaker of course.
A breaker can serve that purpose, in addition to its overcurrent protection. It could also be shunted from a ground fault sensor.
I'm still wanting to find out why a 3-pole breaker cannot support twice the voltage between A and C as it can between A and B and between B and C. Seems no one knows, so they divert the question.
Reply to
phil-news-nospam
Re: 3-pole circuit breaker voltage rating on single phase Group: alt.engineering.electrical Date: Thu, Apr 14, 2005, 5:46am (EDT+4) From: snipped-for-privacy@ipal.net | You just described a "disconnect" perfectly. Minus the part about a breaker of course. A breaker can serve that purpose, in addition to its overcurrent protection. It could also be shunted from a ground fault sensor. I'm still wanting to find out why a 3-pole breaker cannot support twice the voltage between A and C as it can between A and B and between B and C. Seems no one knows, so they divert the question. - who's diverting the question? you are just not making any clear sense. you say you get Vx2 from A-B B-C and not from A-C ? well let's see:)
The Voltage in A - C are Complementary Phases and increase each other, in contrast, the A-B & B-C instead decrease themselves and are opposite or near opposite Phases.
* The voltage will be the same but the current differs proportional to the phase angle < and it will heat up and trip the two phases with the highest current running through them Though' this is at the same voltages applied but different current. values.
Even though all phase voltages are or may be, the same measured individually, the complimentary & oppsosite features of their Combined Distinctive Waveforms (A/B-+) (B/C+-) & (A/C++/--) should be taken into account before assuming voltage capacity discrepancies in a 3Ph Circuit Breaker which has the same dielectric strength in each chamber.
Hence we can conclude that Your view of the breaker function is twisted };-) and not Us.
what else could it be ???
=AEoy
Reply to
Roy Q.T.
| | Re: 3-pole circuit breaker voltage rating on single phase | | Group: alt.engineering.electrical Date: Thu, Apr 14, 2005, 5:46am | (EDT+4) From: snipped-for-privacy@ipal.net | | | You just described a "disconnect" perfectly. Minus the part about a | breaker of course. | A breaker can serve that purpose, in addition to its overcurrent | protection. It could also be shunted from a ground fault sensor. | I'm still wanting to find out why a 3-pole breaker cannot support twice | the voltage between A and C as it can between A and B and between B and | C. Seems no one knows, so they divert the question. | - | who's diverting the question? you are just not making any clear sense.
Then people should say "you aren't making any sense" ... or just ignore me.
| you say you get Vx2 from A-B B-C and not from A-C ? well let's see:) | | The Voltage in A - C are Complementary Phases and increase each other, | in contrast, the A-B & B-C instead decrease themselves and are opposite | or near opposite Phases.
Here I don't know what you are referring to. I don't know what you mean by "instead decrease themselves".
| * The voltage will be the same but the current differs proportional to | the phase angle < and it will heat up and trip the two phases with the | highest current running through them Though' this is at the same | voltages applied but different current. values.
In a single phase system, phase angle is quite a simple thing to deal with.
| Even though all phase voltages are or may be, the same measured | individually, the complimentary & oppsosite features of their Combined | Distinctive Waveforms (A/B-+) (B/C+-) & (A/C++/--) should be taken into | account before assuming voltage capacity discrepancies in a 3Ph Circuit | Breaker which has the same dielectric strength in each chamber. | | Hence we can conclude that Your view of the breaker function is twisted | };-) | and not Us.
You are still jumping to the conclusion that all I want to know is whether my view is twisted or not. So it is. But that's not the question, so saying that isn't answering it.
| what else could it be ???
What else could what be?
I don't think you understand what I asked for at all. Certainly I do not understand every detail of the construction of the breaker. But one thing I do understand is that the spacing between the A-pole and the C-pole is twice that of the spaceing between the A-pole and the B-pole. Do you deny this? Further, there is twice as much dielectric material between the A-pole and the C-pole as there is between the A-pole and the B-pole. This is because between the A-pole and C-pole is the entire B-pole and all of its dielectric.
Each pole has a chamber, and the dielectric enclosure of the chamber should be capable of holding against the L-N voltage applied to that pole since the breaker could well be mounted right up against grounded metal. Further, the dielectric between the A-chamber and B-chamber needs to hold up against the L-L voltage. Since a breaker rated for 480 volt corner grounded delta would have 480 volts all around, you need at least 480 volt withstand between each chamber and outside, as well as chamber to chamber.
But what is the actual dielectric withstand capability when going between chamber A and chamber C? Both the A-B dielectric and the B-C dielectric is involved. With the metal in chamber B held at neutral/ground potential by being attached to neutral or ground (it doesn't have to be switching it, just be connected to it on both ends), that chamber won't be building up any capacitive voltage following that of either A or C. So the A-B dielectric will never see more than 480 volts, and the B-C dielectric will never see any more than 480 volts.
So take an Edison style single phase 2-pole system with 480/960 volts. The L-L voltage is 960 but the L-N voltage is 480. Where will a dielectric in that breaker just described even see 960 volts directly?
What I find intersting is that a typical cheap miniature breaker is rated for 120 volts L-N and 240 volts L-L just fine, and are not suitable for 240 delta of the corner grounded variety (because of 240 volts L-N). This makes sense because in the corner grounded delta, 240 volts would be applied to a dielectric designed for only 120 volts (not counting overdesign that often is included).
So do you yet understand that I am asking about technology, and not the legally listed rating?
Reply to
phil-news-nospam
This is one of those cases where you'll need an OGRED circuit to find out };-)
The fact that a 480/960 vac breaker doesn't ever see the 960 is a through-off, since, when & if 480V is applied L-N on each of the 2 Hot Buses in a 3Phase System the sum on the 2 Hot phases of the 3Ph (orDelta) apparatus will be 960V L-L and still 480 L-N individually.
For that fact, as per your example: a 120/240vac breaker never sees the 240 on a single chamber either.
what's the big deal?
You want to make a Breaker to handle the combined Voltages on a 3Phase Panel all in One Chamber? Why? they are not combined there, only at the apparatus they intend to protect.
ask yourself; does a 3 Phase 120/240 VAC conductor ever carry the entire 240VAC or 2 seperate 120 VAc conductors., why should the breaker be designed to withstand 220VAC?
it's not a technical necessity.
Now a design of a 220, or as in your specific case, a 960VAC Overload for internal protection of X apparatus or appliance is something technical to persue..
other than this: I think you are too close to the rift pal ...
Roy
I'm going to need therapy again if this keeps up unclear to you };-) I am not cross any dimensional portals for you ...
Please step away from the rift ! ;-)
Reply to
Roy Q.T.
| This is one of those cases where you'll need an OGRED circuit to find | out };-) | | The fact that a 480/960 vac breaker doesn't ever see the 960 is a | through-off, since, when & if 480V is applied L-N on each of the 2 Hot | Buses in a 3Phase System the sum on the 2 Hot phases of the 3Ph | (orDelta) apparatus will be 960V L-L and still 480 L-N individually.
What about SINGLE PHASE? I am asking about SINGLE PHASE.
| For that fact, as per your example: a 120/240vac breaker never sees the | 240 on a single chamber either. | | what's the big deal? | | You want to make a Breaker to handle the combined Voltages on a 3Phase | Panel all in One Chamber? Why? they are not combined there, only at the | apparatus they intend to protect.
No. SINGLE PHASE.
| ask yourself; does a 3 Phase 120/240 VAC conductor ever carry the entire | 240VAC or 2 seperate 120 VAc conductors., why should the breaker be | designed to withstand 220VAC?
Since I am talking about single phase power, I don't know what you are referring to with "3 Phase 120/240 VAC". I know what that is, but it is not what I've been asking about. I'm asking about plain and simple single phase Edison style.
So if you had 2 breakers that withstand 120 volts L-N, can you pair them and get 240 volts withstand L-L?
So if you had 2 breakers that withstand 240 volts L-N, can you pair them and get 480 volts withstand L-L?
So if you had 2 breakers that withstand 480 volts L-N, can you pair them and get 960 volts withstand L-L?
They do make breakers specifically designed to withstand 240 volts L-N for 3-phase corner grounded systems. There are 2-pole ones and 3-pole ones. Let's take the 3-pole one and put it on SINGLE PHASE POWER. Now what would it take to get that breaker to withstand 480 volts L-L if L-L is connected to the 2 farthest apart poles (and the middle pole connected to neutral for reference). This is still 240 volts L-N.
| it's not a technical necessity. | | Now a design of a 220, or as in your specific case, a 960VAC Overload | for internal protection of X apparatus or appliance is something | technical to persue..
For 220, I'm not considering 960. I'm only considering when line to line is 2x line to neutral. I don't know of a case where you can have 220 volts line to neutral and get 960 volts line to line (in fact I believe that not to be possible).
The breaker would be wired like this:
A N B G | | | | *-----------* | | | | | | | | +--|--+--|--+--|--+ | | | | | | | | | | | | ( | ( | ( | | | | | | | | | | | | +--|--+--|--+--|--+ | | | | | | *-----------* | | | | | | a n b g
scanerio 1 scenario 2 scenario 3 A-N = 120 volts 240 volts 480 volts N-B = 120 volts 240 volts 480 volts A-B = 240 volts 480 volts 960 volts
Again, although the reference is to a 3-pole breaker, I am talking about single phase power being supplied.
| other than this: I think you are too close to the rift pal ...
You still make some assumptions that are not what I was asking about. You talk about three phase power.
| Roy | | I'm going to need therapy again if this keeps up unclear to you };-) I | am not cross any dimensional portals for you ...
You made an assumption about 960 volts for a 220 volt system, which I am not talking about.
| Please step away from the rift ! ;-)
I'm not at the rift.
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