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Old 11-24-2007, 12:54 PM   #31
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Is it possible to add a 4 way switch to this configuration?


actually it was pretty easy for a DIY'er after reading the posts and figuring out what I actually have. thanks again.

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Old 11-24-2007, 01:02 PM   #32
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Is it possible to add a 4 way switch to this configuration?


Point taken.
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Old 11-24-2007, 01:11 PM   #33
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Is it possible to add a 4 way switch to this configuration?


The issue of using a neutral of one branch circuit for the return on another branch circuit can be one of the worst wiring errors that can be made. In your situation it doesn't appear that you have a worst case situation. What you need to be concerned about in a shared neutral is the addition of return current from loads from two different branch circuits showing up on that single neutral. The problem occurs when those branch circuits have breakers installed on the same leg. This creates a situation where the currents will add together on that one neutral. In typical 15 amp branch circuit on 14/2 g for example the neutral can safely carry 15 amps. But if you use that neutral for loads of another branch circuit on the same buss (leg) in the panel the additional current showing up on the neutral can overload it and you can have a fire because there is no protection on the grounded neutral (white wire) like there is on the ungrounded black wire...ie...the circuit breaker. A breaker will trip out on overload from current being drawn through its hot wire (ungrounded wire). It cannot "see" the current being added to its branch circuit neutral from the other branch circuit tied into it. It would only see current being drawn from loads its branch circuit served. So lets say there are 12 amps on branch circuit #1's neutral but branch circuit #2 has had its neutral tied into branch circuit #1 and it is dumping 15 amps onto #1's neutral. You now have 27 amps on that neutral. This over amperage will exceed the allowed temperature of that 14 guage neutral and a fire will likely occur. Nothing will stop it from overheating as there is no protection from overload on the neutral wire, because the current that is being dumped on #1's neutral from #2 is not being drawn through #1's circuit breaker so it will not "see" the overload.

In your case this situation hasn't occurred... either because the breakers are on opposite legs or both circuits are lightly loaded. The problem gets dangerous if some one starts adding loads to either branch circuit and thereby increasing the neutral current past what the wire can safely carry.

This diagram shows the effect of a stolen neutral from two circuits on the same leg.

The boxes are junction boxes.. ie ..switch boxes or whatever. The loads can be single or multiple loads.

This can be a house burner if the right circumstances happen down the road in the years to come. Personally I would correct the problem if it exists.

Added note: 14 awg has a higher amperage ability in some cases but for simplitiy and the fact it must be breakered at 15 amps for Irichs situation I kept things at a 15 amp parameter.
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Old 11-24-2007, 01:21 PM   #34
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Is it possible to add a 4 way switch to this configuration?


Alan

I see and agree with the california 3 way I drew. I just couldn't for the life of me remember how they wired the thing.
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Old 11-24-2007, 01:38 PM   #35
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Is it possible to add a 4 way switch to this configuration?


I'm going to go out on a limb here sStubbie. I would hazard a guess that not only is a fire not likely to occur at 27A on 14AWG, it would NEVER happen. A lot of safety is built into the code, Stub.

LET THE THRASHINGS CONTINUE
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Old 11-24-2007, 01:52 PM   #36
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Is it possible to add a 4 way switch to this configuration?


here is a link to the other forum where this same question is being discussed.

http://www.selfhelpforums.com/showthread.php?p=65573
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Old 11-24-2007, 02:12 PM   #37
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Is it possible to add a 4 way switch to this configuration?


The only additive to the neutral would be from ONE RECESSED LIGHT. That is the basis of my advice. I'd not rip out frikkin sheetrock over one light. there is no evidence that the neutrals of the two circuits are tied together anywhere. I admit it is fun to ramp up the emotions and mention house burning...but one light?

Is there a chance some one could add to the branch circuits in the future? I guess, but still ain't rippin sheetrock over 1/2 Amp of additive effect on the neutral.

CONTINUE WITH THE BEATINGS

Edit to add...In post 14 I bonked again, caught it re-reading it, Meant to type different instead of the same. The fact is that this switch has worked since 1972. I can quote code and theory all day. One half of one amp adding or subtracting on this circuit isn't going to make me tell Rich to abondan the wiring. The neutral was Hijacked, the neutrals of the two circuits were not tied together. Rich, If you want to solve this mystery once and for all, go buy a meter with an amp clamp on it. Turn on everything on both circuits, pull the panel cover and take readings on the neutral wires in the panel on both circuits. Don't go pulling the panel cover if you don't feel SAFE DOING IT! Post back with the results, I'm dying to here them. If I'm wrong, I'll quit eating Turkey leftovers. That is a big deal!

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Old 11-24-2007, 04:36 PM   #38
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Is it possible to add a 4 way switch to this configuration?


On a 3 phase panel, if you have 3 different circuits used for general lighting loads all on different phases (1,3,5) I think you are allowed to run one neutral for all 3 circuits, if my memory serves me correctly, although plz correct me if im wrong, commercial is not my forte'. So on a 120/240 volt panel wouldnt it be ok to run one neutral for 2 general lighting load circuits as long as the breakers are on opposite phases? It sounds like it would be acting like a mwbc. He says its just one light on the switch so wouldnt just the return current from that one light go through the neutral on the other circuit?

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Old 11-24-2007, 05:02 PM   #39
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Is it possible to add a 4 way switch to this configuration?


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He says its just one light on the switch so wouldnt just the return current from that one light go through the neutral on the other circuit?
That is correct. If the two cicuits are on the same phase, the result would be 1/2A being added to the neutral on the hijacked circuit. If the circuits are on opposite phases then the subtracted, or cancelled. I base 1/2A off of a 65W lamp.

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Old 11-24-2007, 05:26 PM   #40
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Is it possible to add a 4 way switch to this configuration?


Now that I think about it, they did the same thing upstairs in the hallway which has two 3 way's, however, in this case I think they hijacked the neutral from the first circuit. I guess that would balance it out. I'll check into that amp tester as I am curious also and one can never have too many tools. If I get one I will post the results but it will probably be a couple of days. I'm not afraid to take the panel cover off - I worked for an electric co. for about a year and a half and all we did was service work and change fuse boxes into breaker boxes. As far as adding a 3 wire I could do so without damaging much drywall, ( and that is my trade), but I don't want to if it is not necessary. The house has been here for 35 years with the setup and all I did was add a switch. thanks again,

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Old 11-24-2007, 06:04 PM   #41
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Is it possible to add a 4 way switch to this configuration?


Quote:
I'm going to go out on a limb here Stubbie. I would hazard a guess that not only is a fire not likely to occur at 27A on 14AWG, it would NEVER happen. A lot of safety is built into the code, Stub.
Andy .....It generally isn't worth ones time to thrash such immature and irresponsible statement, especially coming from an electrician. I suggest you do a little research instead of wanting others to do it for you. By the way the limb you went out on broke before you finished typing that statement.
I hope there aren't any electricians wiring hospital circuits with your attitude.

Quote:
A lot of safety is built into the code, ......
What in the world is that suppose to mean??
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Old 11-24-2007, 06:24 PM   #42
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Is it possible to add a 4 way switch to this configuration?


Quote:
Originally Posted by Stubbie View Post
Andy .....It generally isn't worth ones time to thrash such immature and irresponsible statement, especially coming from an electrician. I suggest you do a little research instead of wanting others to do it for you. By the way the limb you went out on broke before you finished typing that statement.
I hope there aren't any electricians wiring hospital circuits with your attitude.
Excellent, Stubbie. I wire to code EVERYTIME.



What in the world is that suppose to mean??
14AWG CU is rated to 25A @ 90deg.

Iknow that the house is built in 72 and I know I have to drop to 60deg in this case which makes it 20A. I'm gonna do a bench test tomorrow with gobs of insulation with newspaper surrounding the wire and ramp the 14AWG up to 40A and see if I can start a fire. Bet I don't.

I NEVER SAID THIS WAS CODE COMPLIANT. I also never jumped on the bandwagon of this scenario having a shared neutral, as your beautiful diagram suggests. The neutral isn't switched, as well...So I still ain't tearing up sheet rock over HALF A FRIKKIN AMP!!!

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Old 11-24-2007, 06:26 PM   #43
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Is it possible to add a 4 way switch to this configuration?


Tying the neutrals together, Stub...Which would be additive and bad. BUT THE NEUTRALS AREN'T TIED TOGETHER!!!.

Edit to add: This post was in response to a question posed, and promptly removed.

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Old 11-24-2007, 06:30 PM   #44
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Is it possible to add a 4 way switch to this configuration?


I edited out the last post as I have decided this isn't worth pursuing. BTW your answer is wrong.
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Old 11-24-2007, 06:37 PM   #45
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Is it possible to add a 4 way switch to this configuration?


I'm here to learn Obi-wan, and though immature,I am man enough to admit when I am wrong. Explain how the neutrals are shared. Explain, assuming the circuits are on the same leg, how more than 1/2A is added to the neutral.

When I'm wrong, I admit it. I am FAR from perfect. What am I missing?

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