Quick question - Reg number prohibiting SP RCBOs on TT

[Tech99]

Because you seem hell bent on ignoring the 3rd wire. You do drawings without it, and now you say that 2-phase 3-wire must be nonsense because they called it 1-phase before.

The drawings without the third wire were to illustrate the direction and phase of the currents without that third wire, so that you can see how they don't change when that third wire is added.

Did they call it 1-phase 3-wire before?

Yes.

It wasn't silly, and it was necessary, because another thing you were (and really were, not just seemed to be) hell bent on ignoring was my repeated over and over and over and over again point that you MUST look at it from a particular point of view and that you MUST use the centre point as the point of reference to observe and describe everything from.

Ridiculously large text which can't even be read in full on a modest sized screen is stupid and does nothing to make your point more than a few point sizes larger, bold, underlined, or different colour would do.

And I say that because I started out with the attitude that we have this definition, and I wanted to look at it to see if there's a way which makes it valid, whereas you have started out with the prejudice that it is nonsense and that you will reject anything that shows it not to be nonsense, even if in doing so you engage in willfully ignoring what people say to you over and over again

But you're ignoring what I've pointed out - That adding that third wire in no way changes the instantaneous direction of any of the currents, nor their phase relationship to each other.

You don't seem to be arguing that this is anything but single phase -

- but you want to say that this -

- is, even though I1 & I2 are still flowing in the same direction at any moment, and even though the phase relationship between I1 & I2 hasn't changed in any way. And -

It is the introduction of that 3rd point, the centre point, which brings about the change from single-phase 2-wire to 2-phase 3-wire, therefore that 3rd wire must be of fundamental importance.

Even when R1=R2 so that there's no current flowing in it?

With a balanced load (R1=R2) you will get exactly the same voltage across and current through each resistance with or without that third wire being connected. With a balanced load, connecting that third wire changes nothing in the circuit - No voltages change, no currents change in direction, magnitude or relationship to each other.

And there we have it - one of the most outrageous examples of wriggling and goal post moving it has ever been my displeasure to see here.

Shall I count up the number of times YOU used the concept of consistent north to south travel as a way to say that my argument about it being relative to the observer was nonsense?

I was using north-south as being a relevant concept as we were relating it to things like a car driving along a road, or that train going from London to Liverpool, because relative to the complete distance travelled in those cases north and south remain fixed references.

Obviously if we start talking about crossing the north or south pole that's a rather different kettle of fish because of the nature of the earth and the reference points that we call north and south.

Please tell me who is right, and who is wrong, and why.

Based upon what assumptions?

I never asked, and don't want, you to relate it to an electrical circuit.

But that's what we're discussing. Any anology with something else has to be related to an electrical circuit to make sense.

You're being asked for your observation of what went on from your perspective. Just as you didn't know, when asked, that you were on a Mobius strip you do not have any way to find out, and never will find out, that you were, so there's no "initially assume", there is just your answer.

From your perspective it had changed direction. A different perspective, a different frame of reference, might yield a different answer, but that doesn't make the answer from your perspective wrong, it's the right answer from your perspective.

From my perspective on earth the moon can appear to be almost the same size as the sun. But we all know that it isn't. Just because something appears to be one thing does not necessarily mean that it is - As in the case of your Mobius strip, if the observer is not aware of all the facts he can see things differently from somebody who is looking from outside and can see the whole picture.

No. You can only compare the phase of the two voltages by referencing them to some common point.

That's exactly what I'm doing.

But you can do exactly the same thing with the 2-wire circuit which you seem to accept as being single phase. Pick any point on the circuit as your reference and measure the voltages appearing either side of that point and they'll appear to be out of phase - Because your reference point is between them. But when I tried to explain that you dimissed it as irrelevant because the drawing wasn't showing a 3 wire system.

So I do what you say I can only do, which is to compare the phase of the two voltages by referencing them to some common point, and when I do that and see two different phases (i.e. a non-zero angle between them) I don't have two phases?

You have two voltages which are out of phase relative to that point. You don't seem to understand that you can get that with a simple 2 wire circuit. The point is whether you have more than one phase of current flowing in the circuit. And you don't.

The overall picture remains resolutely 3-phase 4-wire. But it's perfectly OK when your frame of reference changes to just two of those wires for you to say it's single phase?

You can have a single phase supply derived from a 3 phase source. So what?

So, what about circumpolar travel?

Would your direction change as you crossed the North Pole and went from travelling north to travelling south?

Actual direction of movement wouldn't change (no more than it was already doing by following the curvature of the earth anyway). Yes, you'd change from heading to north to heading south, but only because you've just crossed the reference point that we call north.

The fact that a different observer with a different frame of reference will observe something different does not make either one wrong. But I am truly beginning to think that you really do not get that.

But you don't want to see that the argument you're applying to the centre point of the xfmr applies equally to any point on conductor, even one within a 2 wire system which can't be anything but single phase.

Yes, I understand perfectly that things can appear different depending upon one's perspective, but if you can't see the points I've been trying to make by now, I really don't see much point in going into even more car/train analogies.

 

[Tech99]

On p 338 of BS 7671:2008 it lists 2-phase 3-wire.

On p 294 of BS 7671:2001 Amd 1 & 2 it lists 2-phase 3-wire.

Do those 2008 & 2011 publications define that "2 phase 3 wire" as meaning the system we're talking about though? Couldn't they mean two phases plus neutral from a standard UK 240/415V 3-phase supply?

And if that was supposed to mean a 240/480 3-wire supply, then what exactly has that "1 phase 3 wire" option on the forms supposed to have meant?

It's been a supply type in BS 7671 for at least 11 years. It's not new.

So maybe they intended it in 2001 - That's still new compared to the 100+ years of everyone knowing it as single phase before that.

 

[JohnW2]

Do those 2008 & 2011 publications define that "2 phase 3 wire" as meaning the system we're talking about though?

[I presume you mean 2001,not 2011] ...As we keep saying, none of these phrases (all of which go back {in the IET forms} at least to 1992, quite possibly a lot longer) were defined prior to 2011, when the diagrams we've been showing you first appeared in Amendment 1 of BS7671:2008. We can therefore but speculate as to what the IEE/IET meant them to mean prior to 2011. However, in the absence of any 'announcement' about a change, I would think the most likely answer is that they have always intended them to have the meanings which were first shown in those 2011 diagrams (even if others have taken them to mean something different 'for years'). In other words, I now suspect that the most likely truth is that thge IET have never changed their mind.

Kind Regards,John.

 

[ban-all-sheds]

The drawings without the third wire were to illustrate the direction and phase of the currents without that third wire, so that you can see how they don't change when that third wire is added.

Like I say - you are wilfully ignoring the fact that the change the 3rd wire makes is that you use it as the reference point, otherwise its intoduction makes no sense.

Did they call it 1-phase 3-wire before?

Yes.

When?

Not for at least 20 years.

Ridiculously large text which can't even be read in full on a modest sized screen is stupid and does nothing to make your point more than a few point sizes larger, bold, underlined, or different colour would do.

You're right.

I was mistaken in thinking that you hadn't seen any of the times, multiple times, I'd explained that I was talking about changes of direction with respect to the center point. I hadn't realised that you were simply ignoring it, over and over again, because refusing to admit the existence of that concept was the only way you could continue to pretend that there could not possibly be any validity in the term 2-phase 3-wire.

But you're ignoring what I've pointed out - That adding that third wire in no way changes the instantaneous direction of any of the currents, nor their phase relationship to each other.

I'm not ignoring it. I've countered it many many times by pointing out that what's changed from single-phase 2-wire is the introduction of the 3rd wire, and it is therefore the 3rd wire which is to be used as the point of reference. Were it not to be so used then it's introduction would serve no purpose.

Which I realise of course is your position. You have based your entire argument, and your refusal to accept what the 3rd wire must be for, on the IEE/IET being wrong, and having been wrong for decades, and you being right all this time despite what they say.

My position was based on it being unlikely in the extreme that the IEE/IET could have changed something from right to wrong (and now we see that they would have to have been wrong for decades), and that therefore there must be a way to make sense of the changes brought about by the introduction of the 3rd wire

Even when R1=R2 so that there's no current flowing in it?

Yes.

You no more need there to be current flowing in it than you do in the neutral of a 3-phase 4-wire supply for it still to be 3-phase.

With a balanced load (R1=R2) you will get exactly the same voltage across and current through each resistance with or without that third wire being connected. With a balanced load, connecting that third wire changes nothing in the circuit - No voltages change, no currents change in direction, magnitude or relationship to each other.

Indeed not, but as well you know, and as well you are still digging yourself deeper and deeper into the hole of wilfully ignoring it, the changes are relative to the centre point, not to each other.

I was using north-south as being a relevant concept as we were relating it to things like a car driving along a road, or that train going from London to Liverpool, because relative to the complete distance travelled in those cases north and south remain fixed references.

Indeed you were.

Until it broke and showed I was right, whereupon it became silly.

Obviously if we start talking about crossing the north or south pole that's a rather different kettle of fish because of the nature of the earth and the reference points that we call north and south.

Really?

Do you mean that a vehicle travelling towards the north pole is going north, and then as it passes the reference point it is suddenly going south, even though it's been going in a straight line?

Do I hear the sound of a penny dropping?

Please tell me who is right, and who is wrong, and why.

Based upon what assumptions?

Based on two assumptions:

1) You can read

2) You are prepared to stop wriggling. (Pretty unlikely, I admit)

3 observers at the North Pole watching a vehicle approaching them, passing them and leaving them.

A says "It changed direction from coming towards me to going away from me".

B says "It changed direction from travelling north to travelling south."

C says "It never changed direction - it just kept going in a straight line".

Please tell me who is right, and who is wrong, and why.

But that's what we're discussing. Any anology with something else has to be related to an electrical circuit to make sense.

The analogies were to get you to grasp the concept of things changing in direction relative to one observer when they have not necessarily changed relative to another even though they are watching the same event.

And you were quite happy to use them until they broke, whereupon they became silly and stopped making sense.

The fundamental problem, of course, is that you simply cannot allow that concept to exist, because that would mean admitting that the IEe/IET are right and you are wrong.

You're being asked for your observation of what went on from your perspective. Just as you didn't know, when asked, that you were on a Mobius strip you do not have any way to find out, and never will find out, that you were, so there's no "initially assume", there is just your answer.

As in the case of your Mobius strip, if the observer is not aware of all the facts he can see things differently from somebody who is looking from outside and can see the whole picture.

Do you mean that the picture might look different depending on where you look at it from?

Or even that one person might see something that the other can't?

There's your penny dropping again.

But you can do exactly the same thing with the 2-wire circuit which you seem to accept as being single phase. Pick any point on the circuit as your reference and measure the voltages appearing either side of that point and they'll appear to be out of phase - Because your reference point is between them. But when I tried to explain that you dimissed it as irrelevant because the drawing wasn't showing a 3 wire system.

It's not.

As my highlighting shows.

You have two voltages which are out of phase relative to that point. You don't seem to understand that you can get that with a simple 2 wire circuit. The point is whether you have more than one phase of current flowing in the circuit. And you don't.

I do understand.

I also understand that you are perfectly happy to have a point from which reference you'll observe the two different directions of two potential differences but that you refuse to observe the corresponding two different directions of current which those two different direction potential differences must necessarily cause.

The overall picture remains resolutely 3-phase 4-wire. But it's perfectly OK when your frame of reference changes to just two of those wires for you to say it's single phase?

You can have a single phase supply derived from a 3 phase source. So what?

Actual direction of movement wouldn't change (no more than it was already doing by following the curvature of the earth anyway). Yes, you'd change from heading to north to heading south, but only because you've just crossed the reference point that we call north.

And when current passes the reference point we call the 3rd wire it changes from heading towards the point (heading north) to heading away from if (heading south).

But you don't want to see that the argument you're applying to the centre point of the xfmr applies equally to any point on conductor, even one within a 2 wire system which can't be anything but single phase.

And you don't want to see the argument that when a 3rd point is introduced it is not an abstract concept of no referential significance. It changes that "any point on a conductor in a 2-wire system" to the reference point of a 3-wire system from which the other two points are measured.

Yes, I understand perfectly that things can appear different depending upon one's perspective, but if you can't see the points I've been trying to make by now, I really don't see much point in going into even more car/train analogies.

I feel exactly the same, and isn't it funny how you lost your enthusiasm for them right at the time they broke for you, and you were faced with the thought of a train going north and south at the same time.


In summary - you are accusing the IEE/IET of having been wrong for at least 20 years, but can come up with no proof, only repeated arguments which boil down to "I refuse to accept the existence of a concept which if it existed would mean they are not wrong"

 

[ban-all-sheds]

So maybe they intended it in 2001 - That's still new compared to the 100+ years of everyone knowing it as single phase before that.

Keep it up - you may find you do still have some credibility left to lose.

 

[ban-all-sheds]

which people don't like me calling '2-phase'

Becuase it's not!;

Yes it is.

One can not call it 2 phase without then being 180° out of phase from each other.

But as they are 180° apart then, as you say, one can call it 2-phase.