Multi Circuits

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  #1  
Old 04-16-07, 08:00 PM
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Multi Circuits

I have two multi circuits to my kitchen. They both have common, ground, one red wire and one black. The first circuit goes to one pole circuit breakers and are on opposite legs. The next multi circuit goes to a two pole breaker, one red wire and one black wire. That puts them on the same buss and I am sure that is incorrect. I switched one of the wires to the next two pole breaker that puts it on the opposite buss. Am I on the right track here?
 
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Old 04-16-07, 08:08 PM
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If the double-pole breaker occupies two spaces, then the two wires already are on opposite legs of the service. Even if it doesn't occupy two spaces, it may still be okay in certain GE panels (tell us the panel make and model).

If you didn't already know the above, then I'm concerned that you may also not know how to determine if those two single-pole breakers are really on opposite legs.

Also, saying you switched the wire to the "next" breaker is not precise enough information to derive any meaning from. What is the "next" breaker? And how many amps is it? You may taken a safe situation and turned it into a hazard.

Tell us more.
 
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Old 04-16-07, 08:48 PM
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John, I have determined that they are on different leg s by removing the breakers. I have a Murray panel. The double breakers occupy one space and connect to one leg. The next double breaker is a 20 amp. Thanks for your help.
 
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Old 04-17-07, 08:50 PM
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I am wondering if you are talking about a cheater breaker. These are used, when you run out of spaces to use in a panel. The two switches on a cheater breaker, allow you to have two circuits on seperate switches, but they are on the same leg of the service, and will only take up the space of a single breaker.
A two pole breaker occupys two spaces in a panel, this would be attached to both legs of the service.
 
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Old 04-18-07, 03:10 AM
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Yes, they are cheaters and fit in one space and are connected to one leg. Therefor if you put a multi circuit on the cheater they end up on the same leg. That is the situation I had.
 
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Old 04-18-07, 07:24 AM
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The best test to determine if they are on opposite legs is a voltmeter. If you get 240 volts between the two hot wires, then they are on opposite legs. If you get 0 volts, then they are on the same leg (and you have a big problem).

You say that you moved one of the hot wires to the "next" breaker, on the other leg. But what was that "next" breaker doing? Does it serve some other loads? Was it unused?

If you have outlets where both hots are connected to the same receptacle, then you are required to have a common trip lever on the two breakers.

I cannot really tell from here if what you did makes things better or worse. I just don't have enough information.
 
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Old 04-18-07, 11:37 AM
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A proper multi wire circuit is when one neutral (white) is shared between two hots from seperate legs (or phases) of the panel (usually red and black), they should be connected to breakers that are right next to each other (one on top of another), to insure they are on opposite legs. If they happen to be on the same phase, then the neutral wire is carrying twice the load that it should.
 
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Old 04-18-07, 01:27 PM
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One clarifications. The two legs are not phases. House 240 volts is single phase. The legs are electrically out pof phase with each other when you discuss the sine wave of the current, but they are the same phase.

To understand the neutral current, you subtract the current values on the hot wires when the circuit is wired properly, and you add the two current values when the circuit is wired improperly.
 
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Old 04-18-07, 05:06 PM
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"One clarifications. The two legs are not phases. House 240 volts is single phase. The legs are electrically out pof phase with each other when you discuss the sine wave of the current, but they are the same phase."


Actually the two legs on a 120/240v service are different phases.
When Nominal names were decided these were not called "two phase" because that name was already taken by systems where four legs were all hot and 90 deg apart.

What we call (nominaly) 240v single phase is actually two phases 180 deg apart.

Nominal is the name we call it, not what it actually is.
 
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Old 04-18-07, 06:23 PM
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I have to go along with racraft's definition. Since I have worked on two-phase systems (it's a 100 year old building) I get quite irritated at the two legs of a 120/240 single-phase supply being referred to as "phases".

Indeed, what the two legs comprise are the ends of a center-tapped transformer that has a single phase primary.
 
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Old 04-18-07, 06:37 PM
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The sine waves are 180 degrees out of phase, but that does NOT mean two phase.
 
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Old 04-18-07, 08:51 PM
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Wink

I wasn't trying to start a fight....
I was just trying to simplify the terms for the "Average Joe", to understand. The word "leg" or "legs", seems like a funny way to put it, to a layman.

I don't think a real electrician would be asking advice on wiring a three phase wye or delta transformer or motor, using this site.

It's actually a bad idea for electricians to give any advice to a homeowner. The right advice would be, "hire an electrical contractor".
 
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Old 04-18-07, 09:12 PM
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There's no fight here.

I actually think "legs" is a good term. Assuming that you are a man, just stand with your legs a bit apart. The neutral is in between your legs in a single-phase system. A three-phase system is more like two people in a sack race.

Contrary to what you may believe it IS a good idea to give advice to homeowners on small electrical jobs. It makes them more likely to call you when a big job come up.
 
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Old 04-29-07, 11:14 AM
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Been on vacation, so I checked the voltage at the breakers and each of the multi circuits have 240 volts across the black and red. I notied one more multi circuit and the voltage was 240 but the breakers are not next to each other but on seperate legs. Thanks to all of you for help, I am comfortable with the comfortable with what I corrected because of your expertise.
 
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