# Range wiring



## Texas (Dec 11, 2009)

I am looking at the supply to the stove/range (typical stovetop with broiler/oven below) in this old house and want to make sure they did it properly.

I see a #10 ground, two #6 hots, and a #10 neutral, off a double pole 50A breaker. All wires copper, run <50'.
Did they do it correctly?
Thank you.


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## Nestor_Kelebay (Dec 11, 2009)

Can't say about the wire size, but I'll tell you all what I knows for sure...

The 50 amp breakers is right.  Electric ranges come in at least two standard sizes; 30 inch wide for normal residential stoves, and 24 inches wide for "apartment" size stoves.  The bigger ranges will have two 8 inch surface elements (instead of only one) and larger bake and broil elements, and will typically require 50 amp service.  That means 50 amp fuses on BOTH the black and red wires going to the range.  Because there's no designated plug and receptacle configuration for 40 amp, 220 volt service, the smaller apartment size ranges will still use the same cord and plug as the large residential 50 amp ranges, but will typically be fused down to 40 amp service by using two 40 amp fuses or breakers instead of two 50 amp fuses or breakers.

(Electric clothes dryers will typically have two 30 amp fuses and will use a different plug and receptacle configuration designated for 30 amp 220 volt service so that you can't plug a dryer cord into a stove receptacle or vice versa.)

There's a convention in wiring terminal blocks, plugs and receptacles for 220 volt appliances, and that convention is that the three connection points will alway be in a straight line.  The white neutral wire will ALWAYS be connected to the MIDDLE connection point, and the two hot wires (black and red) will be connected on either side of the white wire.  It doesn't matter which side the black and red are on, so long as white is in the middle and black and red are on either side, you're good.  That's true even if you have red connected to black on opposite sides of a terminal block, or if the stove's red wire connects to the prong of the plug that goes into the slot of the receptacle that the house's black wire is connected to.  As long as white's in the middle and the black and red hot wires are on either side in both the plug and receptacle or on both sides of the terminal block, then it's kosher and your karma is in harmony with the universe.

The fourth connection terminal for ground won't be in the same line (cuz that could cause confusion) and will always be easy to recognize cuz it'll be permanently electrically connected to ground and/or the steel electrical box the receptacle is mounted in.

Dunno if this helps any.  Hopefully an electrician in here can confirm that the wire sizes are OK.


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## rdmayers (Dec 12, 2009)

The wire size is correct for a 50 amp circuit,#6 is rated for 60 amps,but what i do not understand is you say the neutral is a #10. In a normal cable all the conductors are the same size except for the ground which would be #10.


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## Nestor_Kelebay (Dec 12, 2009)

Rdmayers:

     It's cuz the black and red wires both carry the same voltage, but they're out of phase by 180 degrees.  As a result, the current and voltage of both the black and red wires (ideally) would cancel each other out perfectly where they meet at the white wire.  So in a perfect world, the current and voltage in the white neutral wire should theoretically both be zero.  How big a wire do you need to carry 0 amps at 0 volts?

But, the real world isn't perfect and Lassie kills chickens.  You'd get close to complete cancellation of the voltage and current in a stove ONLY because the heating elements in it act like almost perfect resistors.  They have almost no reactance.

It's when you put the black and red wires through reactive loads like capacitors (TV sets and CRT computer monitors) or inductive loads (like electric motors and electromagnets) that the current sine waves get out of phase with the applied voltage sine waves.  And, when you have the current and voltage sine waves in both the black and red wires out of sync, when they meet at the white wire they won't cancel out completely, and you can have some residual current and voltage in the white wire.

I'm certainly no expert on this stuff, and I don't want to give that impression.  Hopefully, one of the electricians in here can explain reactive loads better than I did.  But, rest assured, in a resistive load like a toaster, light bulb or kitchen stove, both the voltage and current from the black and red wires will almost completely cancel out where they meet at the white wire, so there won't be nearly as much current or voltage in the white wire as there is in the black or red wires, and so you don't need nearly as big a white wire to carry that small amount of voltage or current.

I have a write-up on my computer hard drive that explains house wiring a bit better.  I wrote it up for a lady that wanted to know how to install a cord and receptacle on her dryer so that she could clean under and behind it easier.  If anybody wants, I can post it here.  It explains about the phase difference between the red and black hot wires in 220 volt wiring and why the voltage and current in the white wire isn't always zero.


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## rdmayers (Dec 12, 2009)

I guess you did not understand what i was saying. Normally all the conductors in a cable are the same size. they do not under size the neutral. So the question i am asking is how there is only a #10 neutral. I understand exactly how everything works.and i also understand that they do not under size the conductors in a cable. I am not questioning if the conductor will carry the load, the only thing the neutral is used for in a electric range is the timer and light. I am just asking how the #10 neutral got there.


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## travelover (Dec 12, 2009)

I think the neutral is there for the 110 volt applications of the range (like the light, timer, etc). As Nestor so succinctly pointed out,  the 220 volt current flow is all through the red and black wire. And the ground wire is just that - a ground wire.


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## Nestor_Kelebay (Dec 12, 2009)

rdmayers said:


> Normally all the conductors in a cable are the same size. they do not under size the neutral. So the question i am asking is how there is only a #10 neutral.



Yes, you are right.  Now that I come to think of it, every range and dryer cord I've ever installed had a white neutral wire of the same gauge as the red and black wires, even though it would appear that it didn't need to be as big.

We need an electrician in here to tell us whether the reason the neutral is the same size just because of electrical code requirements.  It's a guess, but I'm guessing the electrical code requires the neutral to be of the same size in the event of a short circuit.  If the neutral were required to carry the same current as the black or red if the range shorted out, then undersizing the neutral could result in a fire.


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## rdmayers (Dec 12, 2009)

Nobody seems to understand what i am asking. I would like to find out how a #10 neutral got to the range location. I know what the neutral does once it get there. What I am saying is they do not make a romex with 2 #6 and a #10 neutral and a #10 ground. So I just wanted to know how the neutral ended up being a #10. Did they run conduit to the range location and pulled the conductors in it, or did they run a 6-2 with ground an ran a single conductor #10 for the neutral,which would be against code. So for the third time, how is the #10 neutral getting there. That's what i want to find out.
Texas asked the question if it was done correctly.I can not answer this until i find out how the #10 neutral gets there.Is this so had to understand.Everyone want to reply,but nobody want to answer my question


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## Nestor_Kelebay (Dec 12, 2009)

RDMayers:


> Everyone want to reply,but nobody want to answer my question



That's cuz only Texas can answer that question.

Texas: Can you describe the wiring between your electrical panel and your range please.


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## Blue Jay (Dec 12, 2009)

rdmayers said:


> Nobody seems to understand what i am asking. I would like to find out how a #10 neutral got to the range location. I know what the neutral does once it get there. What I am saying is they do not make a romex with 2 #6 and a #10 neutral and a #10 ground. So I just wanted to know how the neutral ended up being a #10. Did they run conduit to the range location and pulled the conductors in it, or did they run a 6-2 with ground an ran a single conductor #10 for the neutral,which would be against code. So for the third time, how is the #10 neutral getting there. That's what i want to find out.
> Texas asked the question if it was done correctly.I can not answer this until i find out how the #10 neutral gets there.Is this so had to understand.Everyone want to reply,but nobody want to answer my question



Can't tell you in this case, I know I have seen older wire with a smaller neutral but they did NOT have the ground wire.


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## speedy petey (Dec 13, 2009)

rdmayers said:


> Texas asked the question if it was done correctly.I can not answer this until i find out how the #10 neutral gets there.Is this so had to understand.Everyone want to reply,but nobody want to answer my question


I don't think any of us can accurately answer this, not just you. 
Texas posted this one and only post two nights ago and has not been back since. EVERYTHING from here on out is purely speculation until (unless) he returns. 


Actually, unless there are other problems/circumstances we don't know about it is likely a compleltey complaint installation.

210.19 Exc. 2 tells us this:
_
*Exception No. 2:*  The neutral conductor of a 3-wire branch circuit supplying a household electric range, a wall-mounted oven, or a counter-mounted cooking unit shall be permitted to be smaller than the ungrounded conductors where the maximum demand of a range of 83/4-kW or more rating has been calculated according to Column C of Table 220.55, but such conductor shall have an ampacity of not less than 70 percent of the branch-circuit rating and shall not be smaller than 10 AWG._


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## Nestor_Kelebay (Dec 13, 2009)

And here I got into a bar fight last night with a guy who insisted that "ampacity" was a real word.  Now I'm going to have to visit him in the hospital and apologize.

OK, so provided that the 10 gauge wire meets the requirement of being able to carry 70 percent of 60 amps, then we can assume the wiring was done by someone who knew the electrical code, and almost certainly did it correctly.

But, RDMayers point still remains, and I'd like to know (and probably all of the other non-electricians in here, too)...  how could that physically be done if you can't buy a cable with an undersized white wire?  Would you run a #6 two conductor cable to the range and then what?  Have the 10 gauge neutral wire strung across the kitchen  ceiling between the electrical panel and the stove and doubling as an indoor clothes line?

Or do they make special cables for ranges with an undersized neutral just because the code allows a smaller neutral in certain circumstances?


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## speedy petey (Dec 13, 2009)

Nestor_Kelebay said:


> And here I got into a bar fight last night with a guy who insisted that "ampacity" was a real word.  Now I'm going to have to visit him in the hospital and apologize.


Well, according to Firefox it is not a word, but I know it is. At least in my world.
Why is he in the hospital? Did he trip walking out to his car and sprain his ankle?  






Nestor_Kelebay said:


> But, RDMayers point still remains, and I'd like to know (and probably all of the other non-electricians in here, too)...  how could that physically be done if you can't buy a cable with an undersized white wire?  Would you run a #6 two conductor cable to the range and then what?  Have the 10 gauge neutral wire strung across the kitchen  ceiling between the electrical panel and the stove and doubling as an indoor clothes line?
> 
> Or do they make special cables for ranges with an undersized neutral just because the code allows a smaller neutral in certain circumstances?


One can only assume conduit. It is certainly feasible.
Since we have yet another MIA thread starter  we may never know.


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## JoeD (Dec 13, 2009)

> It's when you put the black and red wires through reactive loads like capacitors (TV sets and CRT computer monitors) or inductive loads (like electric motors and electromagnets) that the current sine waves get out of phase with the applied voltage sine waves. And, when you have the current and voltage sine waves in both the black and red wires out of sync, when they meet at the white wire they won't cancel out completely, and you can have some residual current and voltage in the white wire.


This is not correct. The only time current flows on the neutral is when you need 120 volts. 240 loads even if they are reactive or inducutive will still cancel each other out. A 240 volt welder is very reactive and it has no neutral.


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## Nestor_Kelebay (Dec 13, 2009)

JoeD said:


> This is not correct. The only time current flows on the neutral is when you need 120 volts. 240 loads even if they are reactive or inducutive will still cancel each other out. A 240 volt welder is very reactive and it has no neutral.



Let me get back to you on this point, Joe.

My understanding is that people often presume there can't be any current through the neutral wire because it's connected to ground in the main panel.  So, if it's grounded at the panel then it supposedly has zero voltage, and therefore can't have any current.  But, ask any dairy farmer, and you'll find out about "dirty electricity" where there are voltages and currents in the neutral wire that interfere with their operations.  There can be enough voltage in supposedly neutral wires to cause cows to stop giving milk because of the tingling they feel from the very small shocks they get.  I'm gonna phone down to the Electrical Engineering Department at the U of M tomorrow and ask what would happen in the neutral wire if there were an inductor connected between the black and neutral and a capacitor connected between the red and neutral.


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## Nestor_Kelebay (Dec 14, 2009)

Joe:

     The University of Manitoba doesn't have anyone who knows anything about house wiring except the electricians employed there.

     I talked to one major electrical contractor this morning and he tells me it's common to have current through the white wire.  When they wire electrical outlets for kitchens, they will often cut the tab between the two outlets on a duplex receptacle and connect one outlet to the black voltage source and the other to the red voltage source.  They do that because it's common for people to blow fuses or trip the breaker to the kitchen electrical outlet because so many things that get plugged in there draw high current (coffee maker, toaster, microwave, electric frying pan, etc.)  So, by providing two 15 amp circuits to that outlet and sharing the neutral, you don't blow as many fuses, but any imbalance in the current ends up going down that shared neutral.  If a toaster and blender are plugged in, you might have 10 amps through the toaster and 3 amps through the blender, and the difference of 7 amps will flow through the neutral.  However, that same electrician told me that even through there is 7 amps in that neutral, there won't be any voltage in that white wire, and that violates the first principle of electricity.  You simply can't have current without a voltage to drive it.

     That electrical contractor suggested I talk to one of the instructors at Winnipeg's Red River College where they train electricians, and I did so.  I could tell that instructor simply didn't know enough about the subject to have any confidence in his answer, and he suggested I talk to the engineering department at Manitoba Hydro.

       Manitoba Hydro employees get every 2nd Monday off, and that just happens to be this Monday.  I will talk to Manitoba Hydro's engineering department tomorrow.

Anyhow, I fully understand that such an "imbalanced load" (as described for a kitchen outlet) is not exactly what we're talking about.  What we're talking about is a current and voltage in the white neutral wire due ENTIRELY to the red and black voltage and current sine waves not cancelling each other out.

I remain convinced that if those red and black sine waves don't cancel out completely, then there simply has to be a resulting current and voltage in the white wire.  There's simply no other option.  I'll talk to Manitoba Hydro tomorrow.


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## Nestor_Kelebay (Dec 15, 2009)

Phoned Manitoba Hydro today, talked to two electrical engineers and one electrical engineering technologist, and none of them knew that residential power consisted of two hot wires and one neutral wire with the two hots out of phase by 180 degrees.  The technologist had no idea who to even refer me to.  One engineer was willing to help, but didn't know that power was delivered via two hots that were 180 degrees out of phase.  The other electrical engineer, a supervisor of the department was asking more questions than me... why do I want to know this, what difference does it make, who am I doing this for, etc. etc. etc.  Then he just lost interest in the discussion and told me he didn't know the answer and didn't know of anyone who might.

This is getting stupid already.  The question isn't difficult, and I'm amazed that no one at Manitoba Hydro is knowledgeable about this.


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## triple D (Dec 16, 2009)

Stop whipping this horse!!!! The only thing in an oven using a neut. is the light bulb, or timer, or cooling fan. The neut is simply not required by code, anywhere, to match current carrying conductor size. Refer to quote in speedy's post.


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## travelover (Dec 17, 2009)

Nestor_Kelebay said:


> ....................This is getting stupid already.  The question isn't difficult, and I'm amazed that no one at Manitoba Hydro is knowledgeable about this.



Well, I'm not surprised considering that they don't even know that hydro means water and electricity is - well, electricity.


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## Nestor_Kelebay (Dec 17, 2009)

Oh ye of little faith!  Be patient.

I am confident that I understand reactance well enough that if you have an inductive load on one leg of 220 volt house wiring and a capacitive load on the other leg, then where the two amperage waves meet at the white wire, there won't be complete cancellation, and there will be some NET amperage in the white wire.

The issue I'm having now is that the voltage sine wave HAS TO BE affected by the inductor.  If it wasn't, then the voltage sine waves would cancel completely, and I'd be standing here saying that there's a net amperage in the white wire WITHOUT any associated driving voltage in that white wire.  (and, like, hey man, you can't have current without a driving voltage)  If there's smoke there fire, and if there's current, there's voltage.

So, that's where things stand right now.  One of these days I'm gonna take a drive down to the U of M.

PS:  The horse tells me that he's wanting to know the answer too.  The horse tells me he's always understood that the current sine wave is affected by impedance, but agrees that the voltage sine waves can't cancel completely cuz then you'd have current without voltage.  He's a smart horse.


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## Blue Jay (Dec 17, 2009)

On a normal range the only time that 110V would come into play would be with the burners on low it would then use the 110V and thus the neutral would come into use and you would have current flow on it but higher settings would use 220V with no neutral involvement.


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## JoeD (Dec 17, 2009)

The is no dispute that if you have any 120 volt loads there can be voltage on the neutral. To have a reacative load on one hot and an inductive load on the other hot you would have to have two separate 120 volt loads. My comment was with regards to 240 volt loads. If only 240 volt loads are present there is no current on the neutral mainly beacause the neutral is not even connected to the loads.


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## Nestor_Kelebay (Dec 17, 2009)

Joe:
       To say that there's no current in the neutral wire of a 220 volt circuit if the neutral wire isn't connected is trivial.  I agree completely.  You can't have any current through a non-existant wire.  But, that wasn't the point I was making when you originally disagreed.

The point I was making (and the question that's confounding me right now) is as follows:

1. Imagine you have a duplex 110 volt receptacle in a kitchen, and the tabs between the receptacles have been cut to allow the upper receptacle to be powered by the black wire and the lower receptacle to be powered by the red wire.  The two receptacles share the same neutral wire back to the panel.

2. Now imagine you were to buy two identical electric toasters and plug one into each of those two receptacles.

3. If you were to turn on both toasters, then you'd have a purely resistive load between the black and white and between the red and white.  Since the black and white amperage and current sine waves are 180 degrees out of phase, then theoretically, the amperage and current sine waves will cancel when they meet at the white wire, and there should be no voltage or current whatsoever in the white wire (theoretically, at least).

4. Now imagine we unplugged one toaster and plugged a big capacitive load (like a TV set) into that receptacle instead.

5.  Now, the red and black amperage sine waves will no longer cancel each other out.  That's because if you consider the two plates of a capacitor, the current OUT of the second plate of the capacitor is going to be highest when the RATE OF CHANGE in voltage of the first plate is highest, and that happens when the voltage sine wave is actually at 0 (zero) volts, like this:







In the above diagram for a capacitor, the red current sine wave (i) out of the capacitor precedes the blue applied voltage sine wave (e), so the two are no longer in phase as they are with a resistor.

You see that for a capacitor, the current flow out of the capacitor is highest when the RATE OF CHANGE in voltage in the first plate is highest, and that actually occurs when the voltage crosses the zero voltage line.  So, the current out of the capacitor is highest when the voltage is at zero volts, and that means that the current sine wave (i) precedes the voltage sine wave (e) by 90 degrees.

(If anyone doesn't understand the above 2 or 3 paragraphs, Google the phrase "ELI the ICEman" without quotes, and you should find plenty on the subject.)

6. So, with one toaster replaced with a TV set, then the capacitive reactance of the TV set causes the current sine wave to occur earlier than the applied voltage sine wave.  Since the other leg (the toaster leg) voltage and sine waves are still in sync, then the current sine waves from the two legs will no longer cancel each other out when they meet at the white wire.

7.  If the two current sine waves occur at a different times, they won't cancel each other out, and that means there HAS TO BE some resulting current in the white wire.

AND, HERE'S WHAT'S CONFOUNDING ME:

With the TV set plugged in, do the red and black voltage sine waves still cancel each other out?  It seems to me that they can't because then you'd have current in the white neutral wire without any driving voltage.

(It seems to me that the voltage sine wave won't be affected as it goes through the capacitor.  As the voltage of the first plate of the capacitor increases, or decreases, it'll induce the same voltage in the second plate of the capacitor.  So, it seems at first blush that the second plate of the capacitor will always be at the same voltage as the first plate of the capacitor, which would mean that the voltage sine wave would be unaffected as it passes through the capacitor.)

And, if none of the electricians in here can explain this to me, then I'm gonna take me a drive down to the U of M to visit some old profs.  The horse is volunteering to go instead cuz he understands the problem completely, but this is a man's job.


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## slownsteady (Dec 18, 2009)

I understand that the horse heard it from the cow.....I'm udderly confused.


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## speedy petey (Dec 18, 2009)

slownsteady said:


> I understand that the horse heard it from the cow.....I'm udderly confused.


That's what happens when you let an engineer roam free on a message board.


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## JoeD (Dec 20, 2009)

Now your getting too technical when you start throwing power factor into it. Put some PCs on the line and watch the netrual current go crazy from harmonics. I have seen 3 phase power with 100 amps on the neutral when all the phases only had between 70-80 amps each.


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## Nestor_Kelebay (Dec 23, 2009)

Patience.

I've contacted a prof in the Electrical Engineering Department at the U of M.  I explained the problem over the phone, but I followed up with an e-mail that he could refer to and pass on to someone else.

He's e-mailed me back saying that he thinks he understands the problem, but it's not really his area of expertise, so he's going to talk to some other people and get back to me.

If anyone wants, I can copy and paste the e-mails in here.

Otherwise, I'll post whatever I find out when I get his response.

PS:
This is not a difficult problem to understand.  If impedance causes the amperage sine wave to go out of phase with the voltage sine wave, then the result is that there'll be a net amperage waveform of some sort in the white wire where the two amperage sine waves from the TV and toaster meet.  But the voltage sine waves from the TV and toaster should still supposedly cancel each other out, so there shouldn't be any voltage in the white wire.

And, that's screwing with my head because you can't have current in the white wire without there being some kind of voltage in that wire to drive that current.

And, if you don't understand the difficulty, then just don't worry about it because it's got nothing to do with whether the original poster's stove is wired properly.  I've run face-first into a problem I can't explain, and so I'm trying to figure it out.

Let's just wait and see what the prof at the U of M finds out, if anything.


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## Texas (Dec 30, 2009)

Sorry to abscond without following up til now.

I have ripped out this cable, and a good many others in this old house.  

For this range I have installed a new 4-conductor copper cable - three awg6 conductors (red, blk, wht neutral) and one awg10 ground wire.
Two 50A ganged breakers.  

End of story!


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## slownsteady (Dec 30, 2009)

I guess this makes nestor the official bulldog of this forum. I don't think he's gonna let go til he chews this one up!

Nestor; that's a compliment.


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## inspectorD (Dec 31, 2009)

Well texas...sounds like you did the sane thing and upgraded. Now you can move on and tackle the next project, hope we didn't scare ya away.


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## Nestor_Kelebay (Jan 7, 2010)

OK, here's a progress report:

I have gotten three e-mails from Arkady Major, a professor of electrical engineering at the U of M so far.  They are as follows:

Hello Nestor,
I think I understand the question, but I can not answer it on my own.  
I will consult with my more knowledgebale colleagues and will get you  
the answer ASAP
regards
Arkady


Hello Nestor,
just a quick thought: aren't the two hot wires 120 degrees out of phase? 
This would solve the problem.
regards
Arkady

Hello Nestor,
> I asked another colleague of mine and you are right, the residential
> power is derived from a single phase (~7.2kV) that is down converted by
> a transformer to 220V. As you mentioned, this transformer has a middle
> tap that produces two hot wires at 110 V each and 180 degrees out of
> phase. Well, at least I managed to get through this stage! I'd say it is
> a good start.
> Unfortunately I was in a rush and did not have enough time to bug him
> about your main question. But I will hunt him down again to get the
> answer.
> regards
> Arkady

for people who just tuned in:
I initially e-mailed Arkady a copy of the post where the duplex receptacle in a kitchen was wired with a black wire to one outlet, a red wire to the other outlet and shared a common neutral.  Then, if we plug identical resistive loads into both outlets, the voltage and current sine waves would both cancel each other out in the neutral wire, and there shouldn't be any current or voltage in the white wire.  But, if we plug a resistive load (like a toaster) into one outlet and a reactive load (like an electric motor or TV set) into the other outlet, then the question becomes: "What happens in that neutral wire?"  The current sine waves won't cancel out any more because they'll arrive at the white wire at slightly different times (cuz of the reactance), and so there has to be some "net" current in the white wire.  If we still presume the voltage sine waves cancel out, then there theoretically should be no voltage in the white wire.  And, the problem then becomes: "How can we have current in that white wire with no voltage to drive it?"

I can see that Arkady realizes this is an interesting problem too.  Otherwise he just would have barfed out some gobbledy-gook about reactance and phase relations just to get rid of me.  The fact that he's trying to find out the answer means he fully understands the problem and is interested in the explanation too.  I'll post back in here when Arkady gets back to me.


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