This is an electrical question. . . .?

Question

I will be using 12/3 Romex to make two separate circuits. As you know, 12/3 is 20 amp wire, for two separate circuits. There is a red wire (hot) for one circuit. There is a black wire (hot) for another circuit. There is a white wire (neutral) for both circuits. In other words, the black wire and the red wire both share the common white wire. Let’s say that one circuit draws 15 amps (red wire) and the second circuit draws another 15 amps (black wire). That is 30 amps. However, they both share the common white wire. The white wire is now carrying substantially in excess of 20 amps. In this case, it is carrying 30 amps and at full load from both circuits, it would have to carry 40 amps. Add it up. It means that the white wire is carrying the voltage from both individual 20 amp circuits (40 amps). The white wire would melt and catch fire instantly. Hence, 12/3 circuits and 12/3 Romex seem dangerous --- but they are used all the time. I don’t understand.
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Answer 1

I guess you asked this 3 times (or more, if I haven't found it yet).

See my complete answer to another one.

The other answers here mention the opposite phases, although some of the details are incorrect. The 120 degree comment is for 3 phase only, and does not apply to your house.

The scary comment is the one that says the 2 phases in the panel are on opposite sides. THIS IS NOT TRUE! Do NOT connect the 2 hots of a 12/3 multiwire branch circuit to breakers that are across from each other (same row). That would put them on the same phase. Opposite phases are next to each other. Double wide (2 pole) breakers are on opposite phases, and are in slots that are next to each other (vertically).

Answer 2

Just connect each circuit to a different phase. In case you are unfamiliar, usually that would mean a breaker on each side of or in your breaker box. You have two "legs" each of "110" coming in to your box. Look at the large wires coming in and you'll notice that they go one each to the two different sides of the breaker panel. So put red on one side, black on the other. The neutral will just connect to the neutral bar. Based on a 20 amp rating, each circuit should handle about 16 amps of draw. You won't need to combine amperages on both circuits. Although it is more expensive and a bit harder to work with, if you'd be more comfortable, you could always get 10/3 wire instead of 12/3.

Answer 3

Red and black circuit should be using two different phases. Therefore, 20A load on circuit A and 20A load on circuit B using the same return line would result in a 20A load on the return for EACH phase, not at the same time.

Answer 4

it's called alternating current ;the power is rising and collapsing. the power comes from a generator with three separate stator/rotors each at 120degrees apart ; there is a time delay between each power surge. this is the 60cycle per second. you must make sure the breakers are on separate phases , do you understand? then its safe

Answer 5

I thought I would be able to answer this question. I will check back for the answer! haha
I think I have a sense for the answer but can't put it into technical terms.


Anjelkake absolutely babe!!!! Unless it's a dual brealer that uses the same side, right?